Effective Pair Programming and Coding and Prompt Engineering and Writing with LLMs like ChatGPT and other AI tools

I’ve been puzzled when I see people online say that LLM’s “don’t write good code”. In my experience, they do. But given that most of these LLMs are used in chatbot mode – meaning you chat and give it instructions to generate the code – that might be where the disconnect lies. To get good code, you need effective prompting and to do so, you need clear thinking and ideas on what you are trying to achieve and how.

My recipe and understanding is:

Clear thinking + clear communication of ideas/request = effective prompting => effective code and other outputs

It also involves understanding what these systems can and can’t do. For example, as I’ve written about before, they can’t “know” things (although they can increasingly look things up) and they can’t do “mental” math. But, they can generally repeat patterns of words to help you see what is known about a topic and they can write code that you can execute (or it can execute, depending on settings) to solve a math problem.

What the system does well is help code small chunks, walk you through processes to link these sections of code up, and help you implement them (if you ask for it). The smaller the task (ask), the more effective it is. Or also – the easier it is for you to see when it completes the task and when it hasn’t been able to finish due to limitations like response length limits, information falling out of the context window (what it knows that you’ve told it); unclear prompting; and/or because you’re asking it to do things for which it doesn’t have expertise. Some of the last part – lack of expertise – can be improved with specific prompting techniques –  and that’s also true for right-sizing the task it’s focusing on.

Right-size the task by giving a clear ask

If I were to ask an LLM to write me code for an iOS app to do XYZ, it could write me some code, but it certainly wouldn’t (at this point in history, written in February 2024), write all code and give me a downloadable file that includes it all and the ability to simply run it. What it can do is start writing chunks and snippets of code for bits and pieces of files that I can take and place and build upon.

How do I know this? Because I made that mistake when trying to build my first iOS apps in April and May 2023 (last year). It can’t do that (and still can’t today; I repeated the experiment). I had zero ideas how to build an iOS app; I had a sense that it involved XCode and pushing to the Apple iOS App Store, and that I needed “Swift” as the programming language. Luckily, though, I had a much stronger sense of how I wanted to structure the app user experience and what the app needed to do.

I followed the following steps:

  1. First, I initiated chat as a complete novice app builder. I told it I was new to building iOS apps and wanted to use XCode. I had XCode downloaded, but that was it. I told it to give me step by step instructions for opening XCode and setting up a project. Success! That was effective.
  2. I opened a different chat window after that, to start a new chat. I told it that it was an expert in iOS programming using Swift and XCode. Then I described the app that I wanted to build, said where I was in the process (e.g. had opened and started a project in XCode but had no code yet), and asked it for code to put on the home screen so I could build and open the app and it would have content on the home screen. Success!
  3. From there, I was able to stay in the same chat window and ask it for pieces at a time. I wanted to have a new user complete an onboarding flow the very first time they opened the app. I explained the number of screens and content I wanted on those screens; the chat was able to generate code, tell me how to create that in a file, and how to write code that would trigger this only for new users. Success!
  4. I was able to then add buttons to the home screen; have those buttons open new screens of the app; add navigation back to the home; etc. Success!
  5. (Rinse and repeat, continuing until all of the functionality was built out a step at a time).

To someone with familiarity building and programming things, this probably follows a logical process of how you might build apps. If you’ve built iOS apps before and are an expert in Swift programming, you’re either not reading this blog post or are thinking I (the human) am dumb and inexperienced.

Inexperienced, yes, I was (in April 2023). But what I am trying to show here is for someone new to a process and language, this is how we need to break down steps and work with LLMs to give it small tasks to help us understand and implement the code it produces before moving forward with a new task (ask). It takes these small building block tasks in order to build up to a complete app with all the functionality that we want. Nowadays, even though I can now whip up a prototype project and iOS app and deploy it to my phone within an hour (by working with an LLM as described above, but skipping some of the introductory set-up steps now that I have experience in those), I still follow the same general process to give the LLM the big picture and efficiently ask it to code pieces of the puzzle I want to create.

As the human, you need to be able to keep the big picture – full app purpose and functionality – in mind while subcontracting with the LLM to generate code for specific chunks of code to help achieve new functionality in our project.

In my experience, this is very much like pair programming with a human. In fact, this is exactly what we did when we built DIYPS over ten years ago (wow) and then OpenAPS within the following year. I’ve talked endlessly about how Scott and I would discuss an idea and agree on the big picture task; then I would direct sub-tasks and asks that he, then also Ben and others would be coding on (at first, because I didn’t have as much experience coding and this was 10 years ago without LLMs; I gradually took on more of those coding steps and roles as well). I was in charge of the big picture project and process and end goal; it didn’t matter who wrote which code or how; we worked together to achieve the intended end result. (And it worked amazingly well; here I am 10 years later still using DIYPS and OpenAPS; and tens of thousands of people globally are all using open source AID systems spun off of the algorithm we built through this process!)

Two purple boxes. The one on the left says "big picture project idea" and has a bunch of smaller size boxes within labeled LLM, attempting to show how an LLM can do small-size tasks within the scope of a bigger project that you direct it to do. On the right, the box simply says "finished project". Today, I would say the same is true. It doesn’t matter – for my types of projects – if a human or an LLM “wrote” the code. What matters is: does it work as intended? Does it achieve the goal? Does it contribute to the goal of the project?

Coding can be done – often by anyone (human with relevant coding expertise) or anything (LLM with effective prompting) – for any purpose. The critical key is knowing what the purpose is of the project and keeping the coding heading in the direction of serving that purpose.

Tips for right-sizing the ask

  1. Consider using different chat windows for different purposes, rather than trying to do it all in one. Yes, context windows are getting bigger, but you’ll still likely benefit from giving different prompts in different windows (more on effective prompting below).Start with one window for getting started with setting up a project (e.g. how to get XCode on a Mac and start a project; what file structure to use for an app/project that will do XYZ; how to start a Jupyter notebook for doing data science with python; etc); brainstorming ideas to scope your project; then separately for starting a series of coding sub-tasks (e.g. write code for the home page screen for your app; add a button that allows voice entry functionality; add in HealthKit permission functionality; etc.) that serves the big picture goal.
  2. Make a list for yourself of the steps needed to build a new piece of functionality for your project. If you know what the steps are, you can specifically ask the LLM for that.Again, use a separate window if you need to. For example, if you want to add in the ability to save data to HealthKit from your app, you may start a new chat window that asks the LLM generally how does one add HealthKit functionality for an app? It’ll describe the process of certain settings that need to be done in XCode for the project; adding code that prompts the user with correct permissions; and then code that actually does the saving/revising to HealthKit.

    Make your list (by yourself or with help), then you can go ask the LLM to do those things in your coding/task window for your specific project. You can go set the settings in XCode yourself, and skip to asking it for the task you need it to do, e.g. “write code to prompt the user with HealthKit permissions when button X is clicked”.

    (Sure, you can do the ask for help in outlining steps in the same window that you’ve been prompting for coding sub-tasks, just be aware that the more you do this, the more quickly you’ll burn through your context window. Sometimes that’s ok, and you’ll get a feel for when to do a separate window with the more experience you get.)

  • Pay attention as you go and see how much code it can generate and when it falls short of an ask. This will help you improve the rate at which you successfully ask and it fully completes a task for future asks. I observe that when I don’t know – due to my lack of expertise – the right size of a task, it’s more prone to give me ½-⅔ of the code and solution but need additional prompting after that. Sometimes I ask it to continue where it cut off; other times I start implementing/working with the bits of code (the first ⅔) it gave me, and have a mental or written note that this did not completely generate all steps/code for the functionality and to come back.Part of why sometimes it is effective to get started with ⅔ of the code is because you’ll likely need to debug/test the first bit of code, anyway. Sometimes when you paste in code it’s using methods that don’t match the version you’re targeting (e.g. functionality that is outdated as of iOS 15, for example, when you’re targeting iOS 17 and newer) and it’ll flag a warning or block it from working until you fix it.

    Once you’ve debugged/tested as much as you can of the original ⅔ of code it gave you, you can prompt it to say “Ok, I’ve done X and Y. We were trying to (repeat initial instructions/prompt) – what are the remaining next steps? Please code that.” to go back and finish the remaining pieces of that functionality.

    (Note that saying “please code that” isn’t necessarily good prompt technique, see below).

    Again, much of this is paying attention to how the sub-task is getting done in service of the overall big picture goal of your project; or the chunk that you’ve been working on if you’re building new functionality. Keeping track with whatever method you prefer – in your head, a physical written list, a checklist digitally, or notes showing what you’ve done/not done – is helpful.

Most of the above I used for coding examples, but I follow the same general process when writing research papers, blog posts, research protocols, etc. My point is that this works for all types of projects that you’d work on with an LLM, whether the output generation intended is code or human-focused language that you’d write or speak.

But, coding or writing language, the other thing that makes a difference in addition to right-sizing the task is effective prompting. I’ve intuitively noticed that has made the biggest difference in my projects for getting the output matching my expertise. Conversely, I have actually peer reviewed papers for medical journals that do a horrifying job with prompting. You’ll hear people talk about “prompt engineering” and this is what it is referring to: how do you engineer (write) a prompt to get the ideal response from the LLM?

Tips for effective prompting with an LLM

    1. Personas and roles can make a difference, both for you and for the LLM. What do I mean by this? Start your prompt by telling the LLM what perspective you want it to take. Without it, you’re going to make it guess what information and style of response you’re looking for. Here’s an example: if you asked it what caused cancer, it’s going to default to safety and give you a general public answer about causes of cancer in very plain, lay language. Which may be fine. But if you’re looking to generate a better understanding of the causal mechanism of cancer; what is known; and what is not known, you will get better results if you prompt it with “You are an experienced medical oncologist” so it speaks from the generated perspective of that role. Similarly, you can tell it your role. Follow it with “Please describe the causal mechanisms of cancer and what is known and not known” and/or “I am also an experienced medical researcher, although not an oncologist” to help contextualize that you want a deeper, technical approach to the answer and not high level plain language in the response.

      Compare and contrast when you prompt the following:

      A. “What causes cancer?”

      B. “You are an experienced medical oncologist. What causes cancer? How would you explain this differently in lay language to a patient, and how would you explain this to another doctor who is not an oncologist?”

      C. “You are an experienced medical oncologist. Please describe the causal mechanisms of cancer and what is known and not known. I am also an experienced medical researcher, although not an oncologist.”

      You’ll likely get different types of answers, with some overlap between A and the first part of answer B. Ditto for a tiny bit of overlap between the latter half of answer B and for C.

      I do the same kind of prompting with technical projects where I want code. Often, I will say “You are an expert data scientist with experience writing code in Python for a Jupyter Notebook” or “You are an AI programming assistant with expertise in building iOS apps using XCode and SwiftUI”. Those will then be followed with a brief description of my project (more on why this is brief below) and the first task I’m giving it.

      The same also goes for writing-related tasks; the persona I give it and/or the role I reference for myself makes a sizable difference in getting the quality of the output to match the style and quality I was seeking in a response.

  • Be specific. Saying “please code that” or “please write that” might work, sometimes, but more often or not will get a less effective output than if you provide a more specific prompt.I am a literal person, so this is something I think about a lot because I’m always parsing and mentally reviewing what people say to me because my instinct is to take their words literally and I have to think through the likelihood that those words were intended literally or if there is context that should be used to filter those words to be less literal. Sometimes, you’ll be thinking about something and start talking to someone about something, and they have no idea what on earth you’re talking about because the last part of your out-loud conversation with them was about a completely different topic!

    LLMs are the same as the confused conversational partner who doesn’t know what you’re thinking about. LLMs only know what you’ve last/recently told it (and more quickly than humans will ‘forget’ what you told it about a project). Remember the above tips about brainstorming and making a list of tasks for a project? Providing a description of the task along with the ask (e.g. we are doing X related to the purpose of achieving Y, please code X) will get you better output more closely matching what you wanted than saying “please code that” where the LLM might code something else to achieve Y if you didn’t tell it you wanted to focus on X.

    I find this even more necessary with writing related projects. I often find I need to give it the persona “You are an expert medical researcher”, the project “we are writing a research paper for a medical journal”, the task “we need to write the methods section of the paper”, and a clear ask “please review the code and analyses and make an outline of the steps that we have completed in this process, with sufficient detail that we could later write a methods section of a research paper”. A follow up ask is then “please take this list and draft it into the methods section”. That process with all of that specific context gives better results than “write a methods section” or “write the methods” etc.

  • Be willing to start over with a new window/chat. Sometimes the LLM can get itself lost in solving a sub-task and lose sight (via lost context window) of the big picture of a project, and you’ll find yourself having to repeat over and over again what you’re asking it to do. Don’t be afraid to cut your losses and start a new chat for a sub-task that you’ve been stuck on. You may be able to eventually come back to the same window as before, or the new window might become your new ‘home’ for the project…or sometimes a third, fourth, or fifth window will.
  • Try, try again.
    I may hold the record for the longest running bug that I (and the LLM) could. Not. solve. This was so, so annoying. No users apparently noticed it but I knew about it and it bugged me for months and months. Every few weeks I would go to an old window and also start a new window, describe the problem, paste the code in, and ask for help to solve it. I asked it to identify problems with the code; I asked it to explain the code and unexpected/unintended functionality from it; I asked it what types of general things would be likely to cause that type of bug. It couldn’t find the problem. I couldn’t find the problem. Finally, one day, I did all of the above, but then also started pasting every single file from my project and asking if it was likely to include code that could be related to the problem. By forcing myself to review all my code files with this problem in mind, even though the files weren’t related at all to the file/bug….I finally spotted the problem myself. I pasted the code in, asked if it was a possibility that it was related to the problem, the LLM said yes, I tried a change and…voila! Bug solved on January 16 after plaguing me since November 8. (And probably existed before then but I didn’t have functionality built until November 8 where I realized it was a problem). I was beating myself up about it and posted to Twitter about finally solving the bug (but very much with the mindset of feeling very stupid about it). Someone replied and said “congrats! sounds like it was a tough one!”. Which I realized was a very kind framing and one that I liked, because it was a tough one; and also I am doing a tough thing that no one else is doing and I would not have been willing to try to do without an LLM to support.

    Similarly, just this last week on Tuesday I spent about 3 hours working on a sub-task for a new project. It took 3 hours to do something that on a previous project took me about 40 minutes, so I was hyper aware of the time mismatch and perceiving that 3 hours was a long time to spend on the task. I vented to Scott quite a bit on Tuesday night, and he reminded me that sure it took “3 hours” but I did something in 3 hours that would take 3 years otherwise because no one else would do (or is doing) the project that I’m working on. Then on Wednesday, I spent an hour doing another part of the project and Thursday whipped through another hour and a half of doing huge chunks of work that ended up being highly efficient and much faster than they would have been, in part because the “three hours” it took on Tuesday wasn’t just about the code but about organizing my thinking, scoping the project and research protocol, etc. and doing a huge portion of other work to organize my thinking to be able to effectively prompt the LLM to do the sub-task (that probably did actually take closer to the ~40 minutes, similar to the prior project).

    All this to say: LLMs have become pair programmers and collaborators and writers that are helping me achieve tasks and projects that no one else in the world is working on yet. (It reminds me very much of my early work with DIYPS and OpenAPS where we did the work, quietly, and people eventually took notice and paid attention, albeit slower than we wished but years faster than had we not done that work. I’m doing the same thing in a new field/project space now.) Sometimes, the first attempt to delegate a sub-task doesn’t work. It may be because I haven’t organized my thinking enough, and the lack of ideal output shows that I have not prompted effectively yet. Sometimes I can quickly fix the prompt to be effective; but sometimes it highlights that my thinking is not yet clear; my ability to communicate the project/task/big picture is not yet sufficient; and the process of achieving the clarity of thinking and translating to the LLM takes time (e.g. “that took 3 hours when it should have taken 40 minutes”) but ultimately still moves me forward to solving the problem or achieving the tasks and sub-tasks that I wanted to do. Remember what I said at the beginning:

    Clear thinking + clear communication of ideas/request = effective prompting => effective code and other outputs

 

  • Try it anyway.
    I am trying to get out of the habit of saying “I can’t do X”, like “I can’t code/program an iOS app”…because now I can. I’ve in fact built and shipped/launched/made available multiple iOS apps (check out Carb Pilot if you’re interested in macronutrient estimates for any reason; you can customize so you only see the one(s) you care about; or if you have EPI, check out PERT Pilot, which is the world’s first and only app for tracking pancreatic enzyme replacement therapy and has the same AI feature for generating macronutrient estimates to aid in adjusting enzyme dosing for EPI.) I’ve also made really cool, 100% custom-to-me niche apps to serve a personal purpose that save me tons of time and energy. I can do those things, because I tried. I flopped a bunch along the way – it took me several hours to solve a simple iOS programming error related to home screen navigation in my first few apps – but in the process I learned how to do those things and now I can build apps. I’ve coded and developed for OpenAPS and other open source projects, including a tool for data conversion that no one else in the world had built. Yet, my brain still tries to tell me I can’t code/program/etc (and to be fair, humans try to tell me that sometimes, too).

    I bring that up to contextualize that I’m working on – and I wish others would work on to – trying to address the reflexive thoughts of what we can and can’t do, based on prior knowledge. The world is different now and tools like LLMs make it possible to learn new things and build new projects that maybe we didn’t have time/energy to do before (not that we couldn’t). The bar to entry and the bar to starting and trying is so much lower than it was even a year ago. It really comes down to willingness to try and see, which I recognize is hard: I have those thought patterns too of “I can’t do X”, but I’m trying to notice when I have those patterns; shift my thinking to “I used to not be able to do X; I wonder if it is possible to work with an LLM to do part of X or learn how to do Y so that I could try to do X”.

    A recent real example for me is power calculations and sample size estimates for future clinical trials. That’s something I can’t do; it requires a statistician and specialized software and expertise.

    Or…does it?

    I asked my LLM how power calculations are done. It explained. I asked if it was possible to do it using Python code in a Jupyter notebook. I asked what information would be needed to do so. It walked me through the decisions I needed to make about power and significance, and highlighted variables I needed to define/collect to put into the calculation. I had generated the data from a previous study so I had all the pieces (variables) I needed. I asked it to write code for me to run in a Jupyter notebook, and it did. I tweaked the code, input my variables, ran it..and got the result. I had run a power calculation! (Shocked face here). But then I got imposter syndrome again, reached out to a statistician who I had previously worked with on a research project. I shared my code and asked if that was the correct or an acceptable approach and if I was interpreting it correctly. His response? It was correct, and “I couldn’t have done it better myself”.

    (I’m still shocked about this).

    He also kindly took my variables and put it in the specialized software he uses and confirmed that the results output matched what my code did, then pointed out something that taught me something for future projects that might be different (where the data is/isn’t normally distributed) although it didn’t influence the output of my calculation for this project.

    What I learned from this was a) this statistician is amazing (which I already knew from working with him in the past) and kind to support my learning like this; b) I can do pieces of projects that I previously thought were far beyond my expertise; c) the blocker is truly in my head, and the more we break out of or identify the patterns stopping us from trying, the farther we will get.

    “Try it anyway” also refers to trying things over time. The LLMs are improving every few months and often have new capabilities that didn’t before. Much of my work is done with GPT-4 and the more nuanced, advanced technical tasks are way more efficient than when using GPT-3.5. That being said, some tasks can absolutely be done with GPT-3.5-level AI. Doing something now and not quite figuring it out could be something that you sort out in a few weeks/months (see above about my 3 month bug); it could be something that is easier to do once you advance your thinking ; or it could be more efficiently done with the next model of the LLM you’re working with.

  • Test whether custom instructions help. Be aware though that sometimes too many instructions can conflict and also take up some of your context window. Plus if you forget what instructions you gave it, you might get seemingly unexpected responses in future chats. (You can always change the custom instructions and/or turn it on and off.)

I’m hoping this helps give people confidence or context to try things with LLMs that they were not willing to try before; or to help get in the habit of remembering to try things with LLMs; and to get the best possible output for the project that they’re working on.

Remember:

  • Right-size the task by making a clear ask.
  • You can use different chat windows for different levels of the same project.
  • Use a list to help you, the human, keep track of all the pieces that contribute to the bigger picture of the project.
  • Try giving the LLM a persona for an ask; and test whether you also need to assign yourself a persona or not for a particular type of request.
  • Be specific, think of the LLM as a conversational partner that can’t read your mind.
  • Don’t be afraid to start over with a new context window/chat.
  • Things that were hard a year ago might be easier with an LLM; you should try again.
  • You can do more, partnering with an LLM, than you can on your own, and likely can do things you didn’t realize were possible for you to do!

Clear thinking + clear communication of ideas/request = effective prompting => effective code and other outputs

Have any tips to help others get more effective output from LLMs? I’d love to hear them, please comment below and share your tips as well!

Tips for prompting LLMs like ChatGPT, written by Dana M. Lewis and available from DIYPS.org

New Survey For Everyone (Including You – Yes, You!) To Help Us Learn More About Exocrine Pancreatic Insufficiency

If you’ve ever wanted to help with some of my research, this is for you. Yes, you! I am asking people in the general public to take a survey (https://bit.ly/GI-Symptom-Survey-All) and share their experiences.

Why?

Many people have stomach or digestion problems occasionally. For some people, these symptoms happen more often. In some cases, the symptoms are related to exocrine pancreatic insufficiency (known as EPI or PEI). But to date, there have been few studies looking at the frequency of symptoms – or the level of their self-rated severity – in people with EPI or what symptoms may distinguish EPI from other GI-related conditions.

That’s where this survey comes in! We want to compare the experiences of people with EPI to people without EPI (like you!).

Will you help by taking this survey?

Your anonymous participation in this survey will help us understand the unique experiences individuals have with GI symptoms, including those with conditions like exocrine pancreatic insufficiency (EPI). In particular, data contributed by people without EPI will help us understand how the EPI experience is different (or not).

A note on privacy:

  • The survey is completely anonymous; no identifying information will be collected.
  • You can stop the survey at any point.

Who designed this survey:

Dana Lewis, an independent researcher, developed the survey and will manage the survey data. This survey design and the choice to run this survey is not influenced by funding from or affiliations with any organizations.

What happens to the data collected in this survey:

The aggregated data will be analyzed for patterns and shared through blog posts and academic publications. No individual data will be shared. This will help fill some of the documented gaps in the EPI-related medical knowledge and may influence the design of targeted research studies in the future.

Have Questions?
Feel free to reach out to Dana+GISymptomSurvey@OpenAPS.org.

How else can you help?
Remember, ANYONE can take this survey. So, feel free to share the link with your family and friends – they can take it, too!

Here’s a link to the survey that you can share (after taking it yourself, of course!): https://bit.ly/GI-Symptom-Survey-All

You (yes you!) can help us learn about exocrine pancreatic insufficiency by taking the survey linked on this page.

MacrosOnTheRun: an iOS app for tracking activity fuel consumption

Last year, I built a spreadsheet template (and shared it here) to use while training and running ultramarathons to track my fuel consumption. It was helpful for me, as a person with exocrine pancreatic insufficiency, to see and decide based on macronutrient counts for each snack how many enzyme pills I needed to take each time I fueled, which is every 30 minutes.

This year, I got tired of messing with the spreadsheet while running. I don’t mind the data entry, but because of the iterative calculations updating with the hourly and overall totals of carbs, sodium, calories per hour etc, the Google Sheet would get bogged down over time, especially when I was running for 16 hours (like during my 100k in March). That would cause the Google Sheets app to crash and reload, or kick me out of the sheet and require me to click back in, wait for it to catch up, before entering my fuel item. It only took a couple of seconds, but it was annoying to have that delay while I was running.

I thought about not logging my fueling while running, especially because I had switched to a slightly more expensive but also larger over-the-counter (OTC) enzyme pill that basically covers every single snack I take with one single pill. That requires less mid-run decision making about how many to take, so it’s less important during the run to see each snack’s composition: I simply swallow a pill each time I do fuel.

Yet, after 1-2 runs of 2-3 hours where I didn’t log my intake, I still found myself missing the data from the run. Although the primary use case of in-run decision making wasn’t there for enzyme dosing, the secondary use case of making sure I was consuming enough sodium per hour and calories per hour relative to my goals was still there. I still wanted to offload that hourly tracking so I didn’t have to remember how much I had had in the last hour. Plus, the post-run data summary was nice, because it helped me evaluate my fueling overall in the grand scheme of my daily nutritional intake, which is particularly helpful for me in making sure I’m consuming enough protein to match my ultra-running activities.

And, I had figured out last year how to develop iOS apps (check out PERT Pilot if you have EPI, and Carb Pilot if you’re someone who’d like to simply use AI to generate estimates of how many carbs or macronutrients are in what you’re eating) with the help of an LLM. So I decided to try to build a custom, just for me app to mimic my spreadsheet in order to easily track my fueling on the run.

Tada! I made MacrosOnTheRun.Macros on the run logo showing "on the run" below the word Macros, stylized to look like 'on the run' is a drop down menu, reminiscent of the fuel list drop down in the app

It’s pretty simple: I open the app, hit ‘start run’, and then click the drop down and tap the fuel item (or electrolyte) that I’m consuming. I hit “add fuel”, and the items drops into the list on the screen and is added to the hourly and overall estimates shown above the drop down.

Screenshot of MacrosOnTheRun showing a pre-populated fuel list to select from and on the right, a screenshot at the end of a 9 hour run with fuel totals and individual fuel items entered
An example during a long run where after the run I open the app to export my in-run data. This is after the run, so you’ll see it’s been 97 minutes since the last fuel when I took that screenshot, and thus the sodium per hour and calories per hour calculation shows 0 given that it’s been >60 minutes since the last fuel. Below that is the total run stats, including enzymes and electrolytes counts. Given that I fuel like clockwork every 30 minutes, you can infer this was a 9 hour run since I took 18 enzymes!

When I’m done with the run, I tap the “stop and export” button at the bottom, which opens the iOS share sheet and enables me to email the CSV file to myself, so I can copy/paste the data back into the same spreadsheet template I was using before. It’s useful because I have all my runs stored as individual tabs in the sheet, and the template (same one I was using last year) autopopulates the pivot table with hourly summaries so I can see across each hour whether I was meeting my sodium and fueling goals. (Check out the 27 hour summary table in my 100 mile recap if you’re curious to see an example!)

Right now, I haven’t bothered to add a feature to edit in-app what the fuel list is – mine is programmed in via the code of the app itself, since I’m the only one using it – and I haven’t published it to the iOS App Store because I didn’t think anyone else would want to use it.

But, if I’m wrong, and this is something you’d like to use – let me know by commenting here or emailing me (Dana+MacrosOnTheRun@OpenAPS.org) and letting me know. If there’s interest, I can modify the app to allow in-app fuel list entry and modifications of the fuel list and then share it via TestFlight or in the App Store for other people to download and use.

Running a Multi-Day Ultramarathon (Aiming for 200 Miles)

I used to make a lot of statements about things I thought I couldn’t do. I thought I couldn’t run overnight, so I couldn’t attempt to run 100 miles. I could never run 200 mile races the way other people did. Etc. Yet last year I found myself training for and attempting 100 miles (I chose to stop at 82, but successfully ran overnight and for 25 hours) and this year I found myself working through the excessive mental logistics and puzzle of determining that I could train for and attempt to run 200 miles, or as many miles as I could across 3-4 days.

Like my 100 mile attempt, I found some useful blog recaps and race reports of people’s official races they did for 200-ish mile races. However, like the 100 attempts, I found myself wanting more information for the mental training and logistical preparation people put into it. While my 200 mile training and prep anchored heavily on what I did before, this post describes more detail on how my training, prep, and ‘race’ experience for a multi-day or 200 mile ultra attempt.

DIY-ing a 200

For context, I have a previous post describing the myriad reasons of why I often choose to run DIY ultras, meaning I’m not signing up for an official race. Most of those reasons hold true for why I chose to DIY my 200. Like my 100 (82) miles, I mapped a route that was based on my home paved trail that takes me out and around the trails I’m familiar with. It has its downsides, but also the upsides: really good trail bathrooms and I feel safe running them. Plus, it’s easy and convenient for my husband to crew me. Since I expected this adventure to take 3-4 days (more on that below), that’s a heavy ask of my husband’s time and energy, so sticking with the easy routes that work for him is optimal, too. So while I also sought to run 200 miles just like any other 200-mile ultra runner, my course happens to have minimal elevation. Not all 200 mile ultramarathon races have a ton of elevation – some like the Cowboy 200 are pretty flat – so my experience is closer to that than the experience of those running mountain based ultras with 30,000 feet (or more) of elevation gain. And I’m ok with that!

Sleep

One of the puzzles I had to figure out to decide I could even attempt a 200 miler is sleep. With a 100 mile race, most people don’t sleep at all (nor did I) and we just run through the night. With 200 miles, that’s impossible, because it takes 3, 4, 5 days to finish and biologically you need sleep. Plus, I need more sleep than the average person. I’m a champion sleeper; I typically sleep much longer than everyone else; and I know I couldn’t function with an hour here or there like many people do at traditional races. So I actually designed my 200 mile ultra with this in mind: how could I cover 200 miles AND get sleep? Because I’m running to/from home, I have access to my kitchen, shower, and bed, so I decided that I would set up my run to run each day and come home and eat dinner, shower, and sleep each night for a short night in my bed.

I then decided that instead of winging it and running until I dropped before eating, showering, and sleeping, I would aim for running 50 miles each day. Then I’d come in, eat, shower, and sleep and get up the next morning and go again. 4 days, 3 nights, 50 miles each day: that would have me finishing around 87-90ish hours total (with the clock running from my initial start), including ~25 hours or more of total downtime between the eating/showering/sleeping/getting ready. That breakdown of 3.67 days is well within the typical finish times of many 200 mile ultras (yes, comparing to those with elevation gain), so it felt like it was both a stretch for me but also doable and in a sensible way that works for me and my needs. I mapped it all out in my spreadsheet, with the number of laps and my routes and pacing to finish 50 miles per day; the two times per day I would need my husband to come out and crew me at ‘aid station stops’ in between laps, and what time I would finish each night. I then factored in time to eat and shower and get ready for bed, sleep, and time to get up in the morning. Given the fact that I expected to run slower each day, the sleep windows go from 8 hours down to less than 6 hours by night 3. That being said, if I managed to sleep 5 hours per night and 15 hours total, that’s probably almost twice as much as most people get during traditional races!

Like sleep, I was also very cognizant of the fact that a 200 probably comes down to mental fortitude and will power to keep going; meticulous fueling; and excellent foot care. Plus reasonable training, of course.

Meticulous fueling

I have previously written about building and using a spreadsheet to track my fuel intake during ultras. This method works really well for me because after each training run I can see how much I consumed and any trends. I started to spot that as I got tired, I would tend to choose certain snacks that happened to be slightly lower calorie. Not by much, but the snack selections went from those that are 150-180 calories to 120-140 calories, in part because I perceived them to be both ‘smaller’ (less volume) and ‘easier to swallow’ when I was tired. Doubled up in the same hour, this meant that I started to have hours of 240 calories instead of more than 250. That doesn’t sound like much, but I need every calorie I can get.

I mapped out my estimated energy expenditure based on the 50 miles per day, and even consuming 250 calories per hour, I would end up with several thousand calories of deficit each day! I spent a lot of time testing food that I think I can eat for dinner on the 3 nights to ensure that I get a good 1000 calories or more in before going to bed, to help address and reduce the growing energy deficit. But I also ended up optimizing my race fuel, too. Because I ran so many long runs in training where I fueled every 30 minutes, and because I had been mapping out my snack list for each lap for 50 miles a day for 4 days, I’ve been aware for months that I would probably get food fatigue if I didn’t expand my fuel list. I worked really hard to test a bunch of new snacks and add them to the rotation. That really helped even in training, across all 12 laps (3 laps a day to get 50 miles, times 4 days), I carefully made sure I wouldn’t have too many repeats and get sick of one food or one group of things I planned to eat. I also recently realized that some of the smaller items (e.g. 120 calorie servings) could be increased. I’m already portioning out servings from a big bag into small baggies; in some cases adding one more pretzel or one more piece of candy (or more) would drive up the calories by 10-20 per serving. Those small tweaks I made to 5 of my ~18 possible snacks means that I added about 200 calories on top of what was already represented in those snacks. If I happen to choose those 5 snacks as part of my list for any one lap, that means I have a bonus 200 calories I’ve convinced myself to consume without it being a big deal, because it’s simply one more pretzel or one more piece of candy in the snack that I’m already use to consuming. (Again, because I’m DIYing my race and have specific needs relative to running with celiac, diabetes, and exocrine pancreatic insufficiency, for me, pre-planning my fuel and having it laid out in advance for every run, or in the race every single lap, is what works for me personally.)

Here’s a view of how I laid out my fuel. I had worked on a list of what I wanted for each lap, checking against repeats across the same day and making sure I wasn’t too heavily relying on any one snack throughout all the days. I then bagged up all snacks individually, then followed my list to lay them out by each lap and day accordingly. I also have a bag per day each for enzymes and electrolytes, which you’ll see on the left. Previously, I’ve done one bag per lap, but to reduce the number of things I’m pulling in and out of my vest each time, I decided I could do one big bag each per day (and that did end up working out well).

Two pictures side by side, with papers on the floor showing left to right laps 1-3 on the top and along the left side days 1-4, to create a grid to lay out my snacks. On the left picture, I have my enzymes, electrolytes per day and then a pile of snacks grouped for each lap. On the right, all the snacks and enzymes and electrolytes have been put into gallon bags, one for each lap.

Contingency planning

Like I did for my 100, I was (clearly) planning for as many possibilities as I could. I knew that during the run – and each evening after the run – I would have limited excess mental capacity for new ideas and brainstorming solutions when problems come up. The more I prepared for things that I knew were likely to happen – fatigue, sore body, blisters, chafing, dropping things, getting tired of eating, etc – the more likely that they would be small things and not big things that can contribute to ending a race attempt. This includes learning from my past 100 attempt and how I dealt with the rain. First of all, I planned to move my race if it looks like we’ll get 6 months of rain in a single 24 hour period! But also, I scheduled my race so that if I do have a few hours of really hard rain, I could choose to take a break and come in and eat/shower/change/rest and go back out later, or extend and finish a lap on the last day or the day after that. I was not running a race that would yank me from the course, but I did have a hard limit after day 5 based on a pre-planned doctor’s appointment that would be a hassle to reschedule, so I needed to finish by the night after day 5. But this gave me the flexibility to take breaks (that I wasn’t really planning to take but was prepared to if I needed to due to weather conditions).

Training for a 200 mile ultramarathon

Like training plans for marathons and 100 milers, the training plans I’ve read about for 200 mile ultramarathons intimidate me. So much mileage! So much time for a slow run/walker like me. I did try to look at sample 200 mile ultra plans and get a sense for what they’re trying to achieve – e.g. when do they peak their mileage before the race, how many back to back runs of what general length in terms of time etc – and then loosely keep that in mind.

But basically, I trained for this 200 mile ultra just like I trained for my marathon, 50k, 100k, and 82 miler. I like to end up doing long runs (which for me are run/walks of 30 seconds run, 60 seconds walk, just like I do shorter runs) of up to around 50k distance. This time, I did two total training runs that were each around 29 miles, just based on the length of the trail I had to run. I could have run longer, but mentally had the confidence that another ~45 minutes per run wasn’t going to change my ability to attempt 50 miles a day for 4 days. If I didn’t have 3 years of this training style under my personal belt, I might feel different about it. That’s longer than many people run, but I find the experience of 7-8 hours of time on my feet fueling, run/walking, and problem solving (including building up my willpower to spend that much time moving) to be what works for me.

The main difference for my 200 is probably also that it’s my 3rd year of ultrarunning. I was able to increase my long runs a little bit more of a time, when historically I used to add 2 miles a time to a long run. I jumped up 4 miles at a time – again, run/walking so very easy on my legs – when building up my long runs, so I was able to end up with 2 different 29 mile runs, two weeks apart, even though I really kicked off training specifically for this 8 weeks prior (10 weeks including taper) to the run. In between I also did a weekend of back to back to back runs (meaning 3 days in a row) where I ran 16 miles, another 16 miles, and 13 miles to practice getting up and running on tired legs. In past cycles I had done a lot more back to back (2-day) with a long and a medium run, but this time I did less of the 2-day and did the one big 3-day since I was targeting a 4-day experience. In future, if I were to do this again, given how well my body held up with all this training, I might have done more back to back, but I took things very cautiously and wanted to not overtrain and cause injury from ramping up too quickly.

As part of that (trying not to over do it), instead of doing several little runs throughout the week I focused on more medium-long runs with my vest and fueling, so I would do something like a long run (starting at 10 miles building up to 29 miles), a medium-long run (8 miles up to 13 miles or 16 miles) and another medium-ish run (usually 8 miles). Three runs a week, and that was it. Earlier in the 8 weeks, I was still doing a lot of hiking off the season, so I had plenty of other time-on-feet experiences. Later in the season I sometimes squeezed in a 4th short run of the week if we wouldn’t be hiking, and ran without my vest and tried to do some ‘speed work’ (aka run a little faster than my easy long run pace). Nothing fancy. Again, this is based on my slow running style (that’s actually a fixed interval of short run and short walk, usually 30 seconds run and 60 seconds walk), my schedule, my personality, and more. If you read this, don’t think my mileage or training style is the answer. But I did want to share what I did and that it generally worked for me.

I did struggle with wondering if I was training “enough”. But I never train “enough” compared to others’ marathon, 50k, 100k, 100 mile plans, either. I’m a low mileage-ish trainer overall, even though I do throw in a few longer runs than most people do. My peak training for marathon, 50k, and 100k is usually around low 50s (miles per week). Surprisingly, this 200 cycle did get me to some mid 60 mile weeks! One thing that also helped me mentally was adding in a rolling 7 day calculation of the miles, not just looking at miles per calendar week. That helped when I shifted some runs around due to scheduling, because I could see that I was still keeping a reasonable 55-low60s mileage over 7 days even though the calendar week total dropped to low 40s because of the way the runs happened to land in the calendar weeks.

Generally, though, looking back at how my training was more than I had accomplished for previous races; I feel better than ever (good fueling really helps!); I didn’t have any accidents or overtraining injuries or niggles; I decided a few weeks before peak that I was training enough and it was the right amount for me.

Another factor that was slightly different was how much hiking I had done this year. I ran my 100k in March then took some time off, promising my husband that we would hike “more” this year. That also coincided with me not really bouncing back from my 100k recovery period: I didn’t feel like doing much running, so we kept planning hiking adventures. Eventually I realized (because I was diagnosed with Graves’ disease last year, I’m having my thyroid and antibody and other related blood work done every 3 months while we work on getting everything into range) that this coincided with my TSH going too high for my body’s happiness; and my disinterest in long runs was actually a symptom (for me) of slightly too-high TSH. I changed my thyroid medication and within two weeks felt HUGELY more interested in long running, which is what coincided with reinvigorating my interest in a fall ultra, training, and ultimately deciding to go for the 200. But in the meantime, we kept hiking a lot – to the tune of over 225 miles hiked and over 53,000 feet of elevation gain! I never tracked elevation gain for hiking before (last year, not sure I retrospectively tracked it all but it was closer to 100 miles – so definitely likely 2x increase), but I can imagine this is definitely >2x above what I’ve done on my previous biggest hiking year, just given the sheer number of hikes that we went out on. So overall, the strengthening of my muscles from hiking helped, as did the time on feet. Before I kicked off my 8 week cycle, we were easily spending 3-4 hours a hike and usually at least two hikes a weekend, so I had a lot of time on feet almost every hike equivalent to 12 or more miles of running at that point. That really helped when I reintroduced long runs and aided my ability to jump my long run in distance by 4 miles at a time instead of more gently progressing it by 2 miles a week as I had done in the past.

How my 200 mile attempt actually went

Spoiler alert: I DNF (did not finish) 200 miles. Instead, I stopped – happily – at 100 miles. But it wasn’t for a lack of training.

Day 1 – 51 miles – All as planned

I set out on lap 1 on Day 1 as planned and on time, starting in the dark with a waist lamp at 6am. It was dark and just faintly cool, but warm enough (51F) that I didn’t bother with long sleeves because I knew I would warm up. (Instead, for all days, I was happy in shorts and a short sleeve shirt when the temps would range from 49F to 76F and back down again.) I only had to run for about an hour in the dark and the sky gradually brightened. It ended up being a cloudy, overcast and nice weather day so it didn’t get super bright first thing, but because it wasn’t wet and cold, it wasn’t annoying at all. I tried to start and stay at an easy pace, and was running slow enough (about ~30s/mile slower than my training paces) that I didn’t have to alter my planned intervals to slow me down any more. All was fairly well and as planned in the first lap. I stopped to use the bathroom at mile 3.5 and as planned at my 8 mile turnaround point, and also stopped to stuff a little more wool in a spot in my shoe a mile later. That added 2 minutes of time, but I didn’t let it bother me and still managed to finish lap 1 at about a 15:08 min/mi average pace, which was definitely faster than I had predicted. I used the bathroom again at the turnaround while my husband re-filled my hydration pack, then I stuffed the next round of snacks in my vest and took off. The bathroom and re-fueling “aid station” stop only took 5 minutes. Not bad! And on I went.

A background-less shot of me in my ultrarunning gear. I'm wearing a grey moisture-wicking visor; sunglasses; a purple ultrarunning vest packed with snacks in front and the blue tube of my hydration pack looped in front; a bright flourescent pink short sleeve shirt; grey shorts with pockets bulging on the side with my phone (left pocket) and skittles and headphones and keys (right pocket), and in this lap I was wearing bright pink shoes. Lap 2 was also pretty reasonable, although I was surprised by how often I wanted a bathroom. My period had started that morning (fun timing), and while I didn’t have a lot of flow, the signals my abdomen was giving my brain was telling me that I needed to go to the bathroom more often than I would have otherwise. That started to stress me out slightly, because I found myself wishing for a bathroom in the longest stretch without trail bathrooms and in a very populated area, the duration of which was about 5.5 miles long. I tried to drink less but was also aware of trying not to under hydrate or imbalance my electrolytes. I always get a little dehydrated during my period; and I was running a multi-day ultra where I needed a lot of hydration and more sodium than usual; this situation didn’t add up well! But I made it without any embarrassing moments on the trail. The second aid station again only took 5 minutes. (It really makes a world of difference to not have to dry off my feet, Desitin them up, and re-do socks and shoes every single aid station like I did last year!) I could have moved faster, but I was trying to not let small minutes of time frazzle me, and I was succeeding with being efficient but not rushed and continuing on my way. I had slowed down some during lap 2, however – dropping from a 15:08 to 15:20ish min/mi pace. Not much, but noticeable.

At sunset, with light blue sky fading to yellow at the horizon behind the row of tall, skinny bush like trees with gaps and a hot air balloon a hundred or so feet off the ground seen between the trees.Lap 3 I did feel more tired. I talked my husband into bringing me my headlamp toward the end of the last lap, instead of me having to carry it for 4+ hours before the sun went down. (Originally, I thought I would need it 2-3 hours into this last lap, but because I was moving so well it was now looking like 4 hours, and it would be a 2-3 mile e-bike ride for him to bring me the lamp when I wanted it. That was a mental win to not have to run with the lamp when I wasn’t using it!) I was still run/walking the same duration of intervals, but slowed down to about 16:01 pace for this lap. Overall, I would be at 15:40 average for the whole day, but the fatigue and my tired feet started to kick in on the third lap between miles 34-51. Plus, I stopped to take a LOT more pictures, because there was a hot air balloon growing in the distance as it was flying right toward me – and then by me next to the trail! It ended up landing next to the soccer fields a mile behind me after it passed me in this picture. I actually made it home right as the sun set and didn’t have to wear my lamp at all that evening.

Day 1 recovery was better and worse than I expected. I sat down and used my foot massager on my still-socked feet, which felt very good. I took a shower after I peeled my socks off and took a look at my feet for the first time. I had one blister that I didn’t know was growing at all pop about an hour before I finished, but it was under some of my pre-taped area. I decided to leave the tape and see how it looked and felt in the morning. I had 2-3 other tiny, not a big deal blisters that I would tape in the morning but didn’t need any attention that night.

I had planned to eat a reasonably sized dinner – preferably around 1000 calories – each night, to help me address my calorie deficit. And I had a big deficit: I had burned 5,447 calories and consumed 3,051 calories in my 13 hours and 13 minutes of running. But I could only eat ¼ of the pizza I planned for dinner, and that took a lot of work to force myself to eat. So I gave up, and went to bed with a 3,846 calorie deficit, which was bigger than I wanted.

And going to bed hurt. I was stiff, which I could deal with, but my feet that didn’t hurt much while running started SCREAMING at me. All over. They hurt so bad. Not blisters, just intense aches. Ouch! I started to doubt my ability to run the next day, but this is where my pre-planning kicked in (aided by my husband who had agreed to the rules we had decided upon): no matter what, I would get up in the morning, get dressed, and go out and start my first lap. If I decided to quit, I could, but I could not quit at night in bed or in the morning in the bed or in the house. I had to get up and go. So I went to sleep, less optimistic about my ability to finish 50 miles again on day 2, but willing to see what would happen.

Day 2: 34 instead of 50 miles, and walking my first ever lap

I actually woke up before my alarm went off on day 2. Because I had finished so efficiently the day before, I was able to again get a good night’s sleep, even with the early alarm and waking up again at 4:30am with plans to be going by 6am. The extra time was helpful, because I didn’t feel rushed as I got ready to go. I spent some extra time taping my new blisters. Because they hadn’t popped, I put small torn pieces of Kleenex against them and used cut strips of kinesio tape to protect the area. (Read “Fixing Your Feet” for other great ultra-related foot care tips; I learned about Kleenex from that book.) I also use lambs’ wool for areas that rub or might be getting hot spots, so I put wool back in my usual places (between big and second toes, and on the side of the foot) plus another toe that was rubbing but not blistered and could use some cushion. I also this year have been trying Tom’s blister powder in my socks, which seems to help since my feet are extra sweat prone, and I had pre-powdered a stack of socks so I could simply slip them on and get going once I had done the Kleenex/tape and wool setup. The one blister that had popped under my tape wasn’t hurting when I pressed on it, so I left it alone and just added loose wool for a little padding.

A pretty view of the trail with bright blue sky after the sun rose with green bushes (and the river out of sight) to the left, with the trail parallel to a high concrete wall of a road with cheery red and yellow leaved trees leaning over the trail.And off I went. I managed to run/walk from the start, and faster than I had projected on my spreadsheets originally and definitely faster than I thought was possible the night before or even before I started that morning. Sure, I was slower than the day before, but 15:40 min/mi pace was nothing to sneeze at, and I was feeling good. I was really surprised that my legs, hips and body did not hurt at all! My multi-day or back-to-back training seemed to pay off here. All was well for most of the first lap (17 miles again), but then the last 2 or so miles, my pace started dipping unexpectedly so I was doing 16+ min/mi without changing my easy effort. I was disappointed, and tired, when I came into my aid station turnaround. I again didn’t need foot care and spent less than 5 minutes here, but I told Scott as I left that I was going to walk for a while, because my feet had been hurting and they were getting worse. Not blisters: but the balls of my feet were feeling excruciating.

A close up of a yellow shelled snail against the paved trail that I saw while walking the world's slowest 17-mile lap on day 2.I headed out, and within a few minutes he had re-packed up and biked up to ride alongside me for a few minutes and chat. I told him I was probably going to need to walk this entire lap. We agreed this was fine and to be expected, and was in fact built into my schedule that I would slow down. I’ve never walked a full lap in an ultra before, so this would be novel to me. But then my feet got louder and louder and I told him I didn’t think I could even walk the full lap. We decided that I should take some Tylenol, because I wasn’t limping and this wouldn’t mask any pain that would be important cues for my body that I would be overriding, but simply muting the “ow this is a lot” screams that the bones in the balls of my feet were feeling. He biked home, grabbed some, and came back out. I took the Tylenol and sent him home again, walking on. Luckily, the Tylenol did kick in and it went from almost unbearable to manageable super-discomfort, so I continued walking. And walking. And walking. It took FOREVER, it felt like, having gone from 15-16 min/mi pace with 30 seconds of running, 60 seconds of walking, to doing 19-20 minute miles of pure walking. It was boring. I had podcasts, music, audiobooks galore, and I was still bored and uncomfortable and not loving this experience. I also was thinking about it on the way back about how I did not want to do a 3rd lap that day (to get me to my planned 50 miles) walking again.

Scott biked out early to meet me and bring me extra ice, because it was getting hot and I was an hour slower than the day before and risking running out of water that lap if he didn’t. After he refilled my hydration pack and brought it back to me while I walked on, I told him I wanted to be done for the day. He pointed out that when I finished this lap, I would be at 34 miles for the day, and combined with the day before (51), that put me at 85 miles, which would be a new distance PR for me since last year I had stopped at 82. That was true, and that would be a nice place to stop for the day. He reminded me of our ‘rules’ that I could go out the next day and do another lap to get me to 100, and decide during that lap what else I wanted to do. I was pretty sure I didn’t want to do more, but agreed I would decide the next day. So I walked home, completing lap 2 and 34 miles for the day, bringing me to 85 miles overall across 2 days.

Day 2 recovery went a little better, in part because I didn’t do 51 miles (only 34) and I had walked rather than ran the second lap, and also stopped earlier in the day (4pm instead of 7pm). I had more time to shower and bring myself to finally eat an entire 1000 calories before going to bed, again with my feet screaming at me. I had more blisters this time, mostly again on my right foot, but the balls of my feet and the bones of my feet ached in a way they never had before. This time, though, instead of setting my alarm to get up and go by 6am, I decided to sleep for longer, and go out a little later to start my first lap. This was a deviation from my plan, but another deviation I felt was the right one: I needed the sleep to help my body recover to be able to even attempt another lap.

Day 3: Only 16 miles, but hitting 100 for the first time ever

Instead of 6am, I set out on Day 3 around 8:30am. I would have taken even longer to go, but the forecast was for a warm day (we ended up hitting 81F) and I wanted to be done with the lap before the worst of the heat. I thought there was a 10% chance I’d keep going after this lap, but it was a pretty small chance. However, I set out for the planned 16 mile lap and was pleasantly surprised that I was run/walking at about a 15:40 pace! Again, better than I had projected (although yes, I had deviated from my mileage plan the day before), and it felt like a good affirmation that stopping the day before instead of slogging out another walking lap was the right thing to do.

After a first few miles, I toyed with the idea of continuing on. But I knew with the heat I probably wouldn’t stand more than one more lap, which would get me to 116. Even if I went out again the fourth day, and did 1-2 laps, that would MAYBE get me to 150, but I doubted I could do that without starting to cause some serious damage. And it honestly wasn’t feeling fun. I had enjoyed the first day, running in the dark, the fog, the daylight, and the twilight, seeing changing fall leaves and running through piles of them. The second day was also fun for the first lap, but the second lap walking was probably what a lot of ultra marathoners call the “death march” and just not fun. I didn’t want to keep going if it wasn’t fun, and I didn’t want to run myself into the ground (meaning to be so worn down that it would take weeks to months to recover) or into injury, especially when the specific milestones didn’t really mean anything. Sure, I wanted to be a 200 mile ultramarathoner, something that only a few thousand people have ever done – but I didn’t want to do it at the expense of my well-being. I spent a lot of time thinking about it, especially miles 4-8, and was thinking about the fact that the day before I had started, I had gone to a doctor’s appointment and had an official diagnosis confirming my fifth autoimmune disease, then proceeded to run (was running) 100 miles. Despite all the fun challenges of running with autoimmune conditions, I’m in really good health and fitness. My training this year went so well and I really enjoyed it. Most of this ultra had gone so well physically, and my legs and body weren’t hurting at all: the weakness was my feet. I didn’t think I could have trained any differently to address that, nor do I think I could change it moving forward. It’s honestly just hard to run that many hours or that many miles, as most ultramarathoners know, and your feet take a beating. Given that I was running on pavement for all of those hours, it can be even harder – or a different kind of hard – than kicking roots and rocks on a dirt trail. I figured I would metaphorically kick myself if I tried for 116 or 134 and injured myself in a way that would take 6-8 weeks to recover, whereas I felt pretty confident that if I stopped after this lap (at 100), I would have a relatively short and easy recovery, no major issues, and bounce back better than I ever have, despite it being my longest ever ultramarathon. Yes, I was doing it as a multi-day with sleep in between, but both in time on feet and in mileage, it was still the most I’d ever done in 2 or 3 days.

And, I was tired of eating. I was fueling SO well. Per my plans, I set out to do >500 mg of sodium per hour and >250 calories per hour. I had been nailing it every lap and every day! Day 1 I averaged 809 mg of sodium per hour and 290 calories per hour. Day 2 was even increased from that, averaging 934 mg of sodium per hour and 303 calories per hour! Given the decreased caloric burn of day 2 because I walked the second lap, my caloric deficit for day 2 was a mere ~882 calories (given that I also managed to eat a full dinner that night), even though I skipped the last hour as I finished the walking lap. Day 3 I was also fueling above my goals, but I was tired of it. Sooooo tired of it. Remember, I have to take a pill every time I eat, because I have exocrine pancreatic insufficiency (EPI or PEI). I was eating every 30 minutes as I ran or walked, so that meant swallowing at least one pill every 30 minutes. I had swallowed 57 pills on Day 1 and 48 pills on Day 2, between my enzymes and electrolyte pills. SO MANY PILLS. The idea of continuing to eat constantly every 30 minutes for another lap of ~5 or more hours was also not appealing. I knew if I didn’t eat, I couldn’t continue.

A chart with an hourly break down of sodium, calories, and carbs consumed per hour, plus totals of caloric consumption, burn, and calculated deficit across ~27 hours of move time to accomplish 100 miles run.

And so, I decided to stop after one more lap on day 3, even though I was holding up a respectable 15:41 min/mi pace throughout. I hit 100 miles and finished the lap at home, happy with my decision.

Two pictures of me leaning over after my run holding a sign (one reading 50 miles, one reading 100 miles) for each of my cats to sniff.(You can see from these two pictures that I smelled VERY interesting, sweaty and salty and exhausted at the end of day 1 and day 3, when I hit 50 miles and 100 miles, respectively. We have two twin kittens (now 3 years old) and one came out to sniff me first on the first day, and the other came out as I came home on the third day!)

Because I had only run one final lap (16 miles) on day 3, and had so many bonus hours in the rest of the day afterward when I was done and home, I was able to eat more and end up with only a 803 calorie deficit for the day. So overall, day 1 had the biggest deficit and probably influenced my fatigue and perception of pain on day 2, but because I had shortened day 2 and then day 3, my very high calorie intake every hour did a pretty good job matching my calorie expenditure, which is probably why I felt very little muscle fatigue in my body and had no significant sore areas other than the bottoms of my feet. I ended up averaging 821 mg/hr of sodium and 279 calories per hour (taking into account the fact that I skipped two final snacks at the end of day 2 when I was walking it out; ignoring that completely skipped hour would mean the average caloric intake on hours I ate anything at all was closer to 290 calories/hr!)

In total, I ended up consuming 124 pills in approximately 27 hours of move time across my 100 miles. (This doesn’t include enzyme pills for my breakfast or dinners each of those days, either – just the electrolyte and enzyme pills consumed while running!)

AFTERMATH

Recovery after day 3 was pretty similar to day 2, with me being able to eat more and limit my calorie deficit. I’ve had long ~30 mile training runs where I wasn’t very hungry afterward, but it surprised me that even two days after my ultra, I still haven’t really regained my appetite. I would have figured my almost 4000 calorie deficit from day 1 would drive a lot of hunger, so this surprised me.

So too has my physical state: 48 hours following the completion of my 100 miles, I am in *fantastic* shape compared to other multi-day back to back series of runs I’ve done, ultramarathons or not. The few blisters I got, mainly on my right foot, have already flattened themselves up and mostly vanished. I think I get more blisters on my right foot because of breaking my toe last year: my right foot now splays wider in my shoe, so it tends to get more blisters and cause more trouble than my left foot. I got only one blister on my left foot, which is still fluid filled but not painful and starting to visibly deflate now that I’m not rubbing it onto a shoe constantly any more. And my legs don’t feel like I ran at all, let alone running 51+34+16 miles!

I am tired, though. I don’t have brain fog, probably because of my excellent fueling, but I am fatigued in terms of overall energy and lack of motivation to get a lot done yesterday and today (other than writing this blog post!). So that’s probably pretty on par with my effort expended and matches what I expected, but it’s nice to be able to move around without hurting (other than my feet).

My feet in terms of general aches and ows are what came out the worst from my run. Day 2, what hurt was the bottom of the balls of my feet. Starting each night though, I was getting aches all over in all of the bones of my feet. After day 3, that night the foot aches were particularly strong, and I took some Tylenol to help with that. Yesterday evening and today though, the ache has settled down to very minor and only occasionally noticeable. The tendon from the top of my left foot up my ankle is sore and gets cranky when I wear my sneakers (although it didn’t bother me at all while running any of the days), so after tying and re-tying my shoelaces 18 times yesterday to try to find the perfect fit for my left foot, today I went on my recovery walk in flip flops and was much happier.

What I’m taking away from this 200 mile attempt that was only 100 miles:

I feel a little disappointed that I didn’t get anywhere near 200 miles, but obviously, I was not willing to hurt long enough or hard enough to get there. My husband called it a stretch goal. Rationally, I am very happy with my choices to stop at 100 and end up in the fantastic physical shape that I am in, and I recognize that I made a very rational choice and tradeoff between ending in good shape (and health) and the mainly ego-driven benefits of possibly achieving 200 miles (for me).

Would I do anything different? I can’t think of anything. If I somehow had an alternate do-over, I can’t think of anything I would think to change. I’d like to reduce my risk of blisters but I’m already doing all I can there, and dealing with changes in my right foot shape post-broken toe that I have no control over. And I’m not sure how to train more/better for reducing the bottom ball of foot pain that I got: I already trained multiple days, back to back, long hours of feet on pavement. It’s possible that having my doctor’s appointment the day before I started influenced my mental calculation of my future risk/benefit tradeoff of continuing more miles, and so not having had that then may have changed my calculations to do another lap or two, or go out on the 4th day (which I did not). But, I don’t have a do over, and I’ll never know, and I’m not too upset about that because I was able to control what I could control and am again pretty happy with the outcomes. 100 or 150 miles felt about the same to me, psychologically, in terms of satisfaction.

What I would tell other people about attempting multiple day ultramarathons or 200 mile ultramarathons:

Training back to back days is one option, as is long spurts of time on feet walking/hiking/running. I don’t think “just running” has to be the only way to train for these things. I’m also a big proponent of short intervals: If you hear people recommend taking walk breaks, it doesn’t have to be 1 minute every 10 minutes or every mile. It can be as short as every 30 seconds of running, take a walk break! There’s no wrong way to do it, whatever makes your body and brain happy. I get bored running longer (and don’t like it); other people get bored running the short intervals that I do – so find what works for you and what you’re actually willing to do.

Having plans for how you’ll rest X hours and go out and try to make it another lap or to the next aid station works really well, especially if you have crew/pacers/support (for me, my husband) who will stick to those rules and help you get back out there to try the next lap/section. Speaking of sleep/rest, laying down for a while helps as much as sleeping, so even if you can’t sleep, committing to the rest of X hours is also good for resting your feet and everything. I found that the hour laying down before I fell asleep helped my body process the noise of the “ouch” from my feet and it was a lot easier to sleep after that. Plan that you’ll have some down/up time before and after your sleep/rest time, and figure that into your time plans accordingly.

The cheesy “know your why” and “know what you want” recommendations do help. I didn’t want 200 miles badly enough to hurt more for longer and risk months of recovery (or the inability to recover). Maybe you’d be lucky enough to achieve 200 without hurting that bad, that long, or risking injury – or maybe you’ll have to make that choice, and you might make it differently than I did. (Maybe you’re lucky enough to not have 5 autoimmune things to juggle! I hope you don’t have to!) I kind of knew going in that I was only going to hit 200 if all went perfect.

Diabetes and this 200 mile ultramarathon that was a 100 mile ultra:

I just realized that I managed to write an ENTIRE race report without talking about diabetes and glucose management…because I had zero diabetes-related thoughts or issues during these several days of my run! Sweet! (Pun fully intended.)

Remember, I have type 1 diabetes and use an open source automated insulin delivery (AID) system (in my case, still using OpenAPS after alllllll these years), and I’ve talked previously about how I fuel while ultrarunning and juggling blood glucose management. Unlike previous ultras, I had zero pump site malfunctions (phew) and my glucose stayed nicely in range throughout. I think I had one small drift above range for 2 hours due to an hour of higher carb activity right when I shifted to walking the second lap on day 2, but otherwise was nicely in range all days and all nights without any extra thought or energy expended. I didn’t have to take a single “low carb”/hypoglycemia treatment! I think there was one snack I took a few minutes early when I saw I was drifting down slightly, but that was mostly a convenience thing and I probably would not have gone low (below target) even if I had waited for my planned fuel interval. But out of 46 snacks, only one 5-10 minutes early is impressive to me.

I had no issues after each day’s run, either: OpenAPS seamlessly adjusted to the increasing insulin sensitivity (using “autosensitivity” or “autosens”) so I didn’t have to do manual profile shifts or overrides or any manual interference. I did decide each night whether I wanted to let it SMB (supermicrobolus) as usual or stick to temp basal only to reduce the risk of hypoglycemia, but I had no post-dinner or overnight lows at all.

The most “work” I had to do was deciding to wear a second CGM sensor (staggered, 5 days after my other one started) so that I had a CGM sensor session going with good quality data that I could fall back to if my other sensor started to get jumpy, because the sensor session was supposed to end the night of day 4 of my planned run. I obviously didn’t run day 4, but even so I was glad to have another sensor going (worth the cost of overlapping my sensors) in order to have the reassurance of constant data if the first one died or fell out and I could seamlessly switch to an already-warmed up sensor with good data. I didn’t need it, but I was glad to have done that in prep.

(Because I didn’t talk about diabetes a lot in this post, because it was not very relevant to my experiences here, you might want to check out my previous race recaps and posts about utlrarunning like this one where I talk in more detail about balancing fueling, insulin, and glucose management while running for zillions of hours.)

TLDR: I ran 100 miles, and I did it my DIY way: my own course, my own (slow pace), with sleep breaks, a lot of fueling, and a lot of satisfaction of setting big goals and attempting to achieve them. I think for me, the process goals of figuring out how to even safely attempt ultramarathons are even more rewarding than the mileage milestones of ultrarunning.

Running a multi-day ultramarathon by Dana M. Lewis from DIYPS.org

What I’ve Learned From 5,000 Pills Of Pancreatic Enzyme Replacement Therapy (PERT) For Exocrine Pancreatic Insufficiency (EPI/PEI)

I recently reached a weird milestone that no one likely cares about, but that I find fascinating: in the first 534 days of exocrine pancreatic insufficiency (EPI / PEI), I’ve taken more than 5,000 pills of pancreatic enzyme replacement therapy (PERT).

That’s an average of 9.41 pills per day!

PERT (enzymes) helps my body successfully digest the food that I eat, because my pancreas is no longer producing enough enzymes. Like insulin treatment for diabetes, PERT will be a lifelong necessity for me: this number of pills consumed is one that only goes up from here.

Here’s a look at what the pills per day intake has looked like over this time:

  • Min: 2 (early days)
  • Max: 72 (hello, outlier of two ultramarathons! One was 62 miles, the other was 82 miles! Other 30-40+ pill days are likely also ultra 🏃🏼‍♀️ training days, e.g. around 50k of running, which is still 8-9 hours of running and fueling every 30 minutes)
  • Median: 8

Analyzing a graph of my daily PERT enzyme pills, there are noticeable spikes, particularly around my ultramarathon training days. Two distinct spikes at 72 pills per day correspond to my 100k (62 mile) and 82-mile ultra runs.

Here is a graph showing my PERT (enzyme) pills per day totals, there are a few noticeable spikes in the 20-40ish range that are likely ultra training days. The two spikes around 72/day are my 100k (62 mile) and 82 mile ultra runs.

Why so many pills?!

Not everyone with EPI takes as many pills as I do. The number is titrated (adjusted) based on what and how often I eat. A typical meal for me requires 2-3 prescription pills of PERT.

In my case, I sometimes use over-the-counter (OTC) enzymes to ‘top off’ a prescription pill.

For hikes and runs, which I do 4-5 times each week, I eat small amounts every 30 minutes if I’m out for more than 2 hours, which is 3+ times a week. For a run of 5 hours, where I consume 10 snacks, I’d use 10 pills if I went the prescription route. In contrast, I usually use 2-4 OTC pills per snack, which combined costs an average of $0.70. That means $7 in enzyme costs for 5 hours compared to $80 if I had taken prescription PERT! Multiply times several times a week, and you can see why I choose this strategy.

Balancing Cost ($) and Convenience (Fewer Pills)

The “cost” for using OTC pills, though, is 20-40 pills ($7) instead of 10 pills ($80). On a day-to-day basis, my choice depends on convenience, how confident I am in my counts/dosing (I’m very confident for hike/run pre-portioned snacks that I’ve tested rigorously), and other factors.

Increasingly, when I’m not pursuing physical activity, I’m more likely to choose fewer pills at the financial cost of prescription PERT. I’d like to choose fewer pills for physical activity, too, which is why I’ve recently shifted to a slightly more expensive OTC pill that has more enzymes in it, in order to take 1 pill for most snacks instead of 2-4. In a typical long run of 4 hours, for example, instead of 7 snacks resulting in 28 pills, those 7 snacks would instead result in 7 pills! (There’s also a challenge with finding these particular OTC pills, as prescription pill shortage has driven more people to try OTCs and now the OTC pills I prefer are regularly out of stock, too. If you’re curious about using OTC pills with EPI, or prior to a diagnosis of EPI, you may be interested in this post where I describe in more detail using over the counter (OTC) enzyme pills for this purpose.)

Long run days are outliers in my pill count per day numbers and graphs. However, even if I skipped those and only took 8 prescription PERT per day, I’d still have consumed over 4,200 enzyme pills at this point.

EPI or PEI leads to a lot of pill-swallowing, regardless of whether you’re using over the counter enzymes or prescription enzymes.

But they work! Oh, do they work. My GI symptoms used to be most days a week and caused me to feel miserable (read about my experience getting diagnosed with EPI here). Now, I rarely have any symptoms, and when they do occur (likely mistiming a dose compared to what I was eating or taking not quite enough to match what I was eating), they are significantly less bothersome. It’s awesome, and I feel back to “normal” for me well before all of my GI symptoms started years ago! So yes, I have to swallow many pills a day for EPI but my symptoms are completely and regularly managed as a result and my quality of life is back to being what it was before.

If you’re curious to read more about my experiences with EPI, or posts about adjusting enzymes to match what you’re eating, check out DIYPS.org/EPI for a list of other EPI related posts.

If you have EPI and have an iOS device, you also might be interested in checking out PERT Pilot, a free iOS app to track food intake and PERT dosing and outcomes.


You can also contribute to a research study and help us learn more about EPI/pEI – take this anonymous survey to share your experiences with EPI-related symptoms!

You’d Be Surprised: Common Causes of Exocrine Pancreatic Insufficiency

Academic and medical literature often is like the game of “telephone”. You can find something commonly cited throughout the literature, but if you dig deep, you can watch the key points change throughout the literature going from a solid, evidence-backed statement to a weaker, more vague statement that is not factually correct but is widely propagated as “fact” as people cite and re-cite the new incorrect statements.

The most obvious one I have seen, after reading hundreds of papers on exocrine pancreatic insufficiency (known as EPI or PEI), is that “chronic pancreatitis is the most common cause of exocrine pancreatic insufficiency”. It’s stated here (“Although chronic pancreatitis is the most common cause of EPI“) and here (“The most frequent causes [of exocrine pancreatic insufficiency] are chronic pancreatitis in adults“) and here (“Besides cystic fibrosis and chronic pancreatitis, the most common etiologies of EPI“) and here (“Numerous conditions account for the etiology of EPI, with the most common being diseases of the pancreatic parenchyma including chronic pancreatitis, cystic fibrosis, and a history of extensive necrotizing acute pancreatitis“) and… you get the picture. I find this statement all over the place.

But guess what? This is not true.

First off, no one has done a study on the overall population of EPI and the breakdown of the most common co-conditions.

Secondly, I did research for my latest article on exocrine pancreatic insufficiency in Type 1 diabetes and Type 2 diabetes and was looking to contextualize the size of the populations. For example, I know overall that diabetes has a ~10% population prevalence, and this review found that there is a median prevalence of EPI of 33% in T1D and 29% in T2D. To put that in absolute numbers, this means that out of 100 people, it’s likely that 3 people have both diabetes and EPI.

How does this compare to the other “most common” causes of EPI?

First, let’s look at the prevalence of EPI in these other conditions:

  • In people with cystic fibrosis, 80-90% of people are estimated to also have EPI
  • In people with chronic pancreatitis, anywhere from 30-90% of people are estimated to also have EPI
  • In people with pancreatic cancer, anywhere from 20-60% of people are estimated to also have EPI

Now let’s look at how common these conditions are in the general population:

  • People with cystic fibrosis are estimated to be 0.04% of the general population.
    • This is 4 in every 10,000 people
  • People with chronic pancreatitis combined with all other types of pancreatitis are also estimated to be 0.04% of the general population, so another 4 out of 10,000.
  • People with pancreatic cancer are estimated to be 0.005% of the general population, or 1 in 20,000.

What happens if you add all of these up: cystic fibrosis, 0.04%, plus all types of pancreatitis, 0.04%, and pancreatic cancer, 0.005%? You get 0.085%, which is less than 1 in 1000 people.

This is quite a bit less than the 10% prevalence of diabetes (1 in 10 people!), or even the 3 in 100 people (3%) with both diabetes and EPI.

Let’s also look at the estimates for EPI prevalence in the general population:

  • General population prevalence of EPI is estimated to be 10-20%, and if we use 10%, that means that 1 in 10 people may have EPI.

Here’s a visual to illustrate the relative size of the populations of people with cystic fibrosis, chronic pancreatitis (visualized as all types of pancreatitis), and pancreatic cancer, relative to the sizes of the general population and the relative amount of people estimated to have EPI:

Gif showing the relative sizes of populations of people with cystic fibrosis, chronic pancreatitis, pancreatic cancer, and the % of those with EPI, contextualized against the prevalence of these in the general population and those with EPI. It's a small number of people because these conditions aren't common, therefore these conditions are not the most common cause of EPI!

What you should take away from this:

  • Yes, EPI is common within conditions such as cystic fibrosis, chronic pancreatitis (and other forms of pancreatitis), and pancreatic cancer
  • However, these conditions are not common: even combined, they add up to less than 1 in 1000!
  • Therefore, it is incorrect to conclude that any of these conditions, individually or even combined, are the most common causes of EPI.

You could say, as I do in this paper, that EPI is likely more common in people with diabetes than all of these conditions combined. You’ll notice that I don’t go so far as to say it’s the MOST common, because I haven’t seen studies to support such a statement, and as I started the post by pointing out, no one has done studies looking at huge populations of EPI and the breakdown of co-conditions at a population level; instead, studies tend to focus on the population of a co-condition and prevalence of EPI within, which is a very different thing than that co-condition’s EPI population as a percentage of the overall population of people with EPI. However, there are some great studies (and I have another systematic review accepted and forthcoming on this topic!) that support the overall prevalence estimates in the general population being in the ballpark of 10+%, so there might be other ‘more common’ causes of EPI that we are currently unaware of, or it may be that most cases of EPI are uncorrelated with any particular co-condition.

(Need a citation? This logic is found in the introduction paragraph of a systematic review found here, of which the DOI is 10.1089/dia.2023.0157. You can also access a full author copy of it and my other papers here.)


You can also contribute to a research study and help us learn more about EPI/PEI – take this anonymous survey to share your experiences with EPI-related symptoms!

Air Quality, CO2 monitoring, and Situational Masking

I do a lot of things most people don’t want to do themselves – and I get that. (For example, recording macronutrients while running? Running for up to 16 or 25 hours? Let alone other choices like building DIY and making open source automated insulin delivery systems not only for myself but more widely available for other people.) I’ve also talked before about functional self-tracking and how I don’t track things for the sake of tracking, I track when the data/information is actionable either retrospectively or in real-time.

I’ve spent enough time now collecting real-time data on air quality (via a proxy of CO2 levels) that I think it would be useful to share for other people to consider the retrospective data for THEIR decision making.

You may not want (or be able to afford) a CO2 monitor, and you may not want to mask inside all the time, but the below outlines the general scenarios in which air quality tends to be better or worse and when you would get the most benefit from situational masking in response to those situations.

(Think about situational masking indoors like you think about situational masking for smoke and poor air quality outside. Most of the time, you likely don’t mask outside. But if you’re on the east coast right now or have lived through a previous west coast US summer with a “smoke season”, you’ve probably experienced multi-day air quality outside that was so poor that you considered or did wear a high-quality (N95/K95) mask outside or limit your time exposed to that outdoor air.)

Air quality assessment via CO2 monitoring

In the last few years, Scott and I acquired two different CO2 monitors. The first was cheap, required to be plugged into a battery pack to run it, and was simply viewable on the device display. It was useful to start to get a sense for what the CO2 levels were in indoor spaces as compared to outdoor air.

Later, we decided to invest in an Aranet CO2 monitor, which runs on two AA batteries and lasts months on a single pair of batteries. You can view the data on the device display AND see a retrospective and realtime graph of the data in your phone, because it connects via Bluetooth. You can see not only CO2 but also temperature, humidity, and air pressure.

We have found this useful because CO2 is something that we all produce when we breathe out. The more we breathe out, and the more people that are breathing out, the higher the CO2 levels. The more of that air that is replaced with low-CO2 outside air, the lower the CO2 levels. Measuring the CO2 then helps us understand the ventilation (how much air is flowing through the space and how often it is being cleared out) and the risks of being in that space. A higher CO2 level means more people and/or less air being cleared out of the space, meaning  you are more likely to be breathing in what someone else is breathing out.

How we evaluate CO2 levels

An outdoor CO2 level would be around ~450 ppm in urban areas, or as low as 400 ppm out in nature. Since a perfectly-ventilated space would be 100% outside air, we want to compare any indoor air CO2 reading to outdoor air.

For example, at home in our enclosed apartment with 2 people (and 2 cats), we typically run around 700 ppm, which means ~250 ppm above outdoor air levels. When we open our door or a window, it drops to ~500 ppm, or only ~50 ppm above outdoor air levels. Given that we have confirmed our air intake into our HVAC system for our apartment is outdoor air, this means the ~250 ppm we are sharing between the two of us is just our (and the cats) exhalations, rather than anyone outside our household. So those levels are acceptable to us, but our choice of interventions would change if we were sharing air with other people, especially random strangers. (Stranger danger is one way to think about air, further contextualized below with data.)

In a shared space with random strangers, your risk of COVID aerosol-based transmission is proportional to how elevated the CO2 level is above that of outside air, and the amount of time spent in that space. So a CO2 reading of 650 ppm, which is ~200 ppm over outside air, would be half as risky as a reading of 850 ppm, or ~400 ppm over outside air. And timing matters, so a 1 hour bus ride or the hour you spend boarding and waiting for takeoff on your plane when CO2 levels are highest and the air filtration (see below) is off will be of greater risk than short exposure to the same levels.

Now, we’ve also used our CO2 monitors in many other places, such as in airports and on planes and other public transportation, and other indoor shared spaces like grocery stores etc.

Here’s what we’ve learned about where CO2 levels trend (based on our repeated but n=1 testing).

Trains, buses, and rideshare (e.g. Uber, Lyft, etc) = BAD NEWS BEAR AIR

Public transportation, in every location and every country we have been in, has much higher CO2 levels.

What do I mean by much higher? Often 1000-1500 ppm easily (and sometimes >2000 ppm), which is anywhere from 500-1500 ppm above outdoor air quality.

Trains/metros/light rail where the doors are constantly opening and closing to outdoor air would seem like they would be better, but sometimes they still have (due to the density of riders) >1500 ppm.

Buses where you can’t open the window can be as high of CO2 levels as planes, without the benefit of air exchange or HEPA filtration of the air. Our recent 20 minute bus ride was up to >2500 ppm on a full bus.

Watch out for rideshares, too. Often times we get in a rideshare and the driver intentionally or accidentally has “recirc” or “recirculating air” on, meaning the air isn’t exchanged outside and the driver and riders are re-breathing each other’s air over and over and over and over again..yikes. Specifically looking at the console when you get in the car is useful: if you see the recirc button lit up, ask the driver to turn it off. If they don’t understand or refuse, or you don’t want to try to explain it, opening a window helps immensely to reduce the CO2 levels and the amount of re-breathing air. (The recirc icon usually looks like a car with a U-shaped arrow on it).

Planes (including airports, during boarding, in flight, and during landing/deplaning) = ALSO BAD NEWS BEAR AIR

Airports sometimes have better-ventilated spaces: you can often find less crowded corners of a terminal and see CO2 readings of <900 ppm. However, it’s still pretty common to be in the airport and see >1000 ppm, meaning that the CO2 is >500 ppm above outdoor air quality, and it is air from a whole assortment of random strangers coming and going, so it’s less safe than the air you’d be breathing in at home or in private spaces.

When boarding, both standing close in line with other people but also on the jet bridge and while you are on the plane, is usually even HIGHER CO2 levels than the airport. The typical air for a plane (that they tout with HEPA filters and high air exchange rates) is not turned on until you start to take off, and then it takes some time to exchange all of the air. This means there is a MUCH higher rate of re-breathing other people’s air while boarding and until you are in the air.

Now, we have measured CO2 levels during all of these times. If indoor airport air is around 900 ppm, it usually jumps to 1100-1300 on the jetbridge (if you’ve got a backed up line) and when you’re sitting on the plane watching other people board, it can go up to 2500+. And then it continues to go up as you have a full flight of people breathing in this enclosed space. During flight, we’ve seen CO2 levels hover between 1700-3000 ppm, and in some cases have gone up to ~4000 ppm. This is a lot of CO2! However, there are HEPA filters cleaning the ~half of the air that is recirculated instead of replaced. So, it’s harder to say when the airplane air systems ARE running (during most of the flight) whether the risk is as high (for infectious disease transmission) as it is in other environments that aren’t studiously exchanging and HEPA-filtering any recirculated air.

Note that when they spin down the engines after landing and all the way through taxiing, deplaning, and getting back into the airport – the CO2 level again tends to rise because they again change the air flow when they’re on the ground. So like standing in line to get on or waiting for other people to board, standing in line to get off/waiting for everyone to get off produces high CO2 levels *without the benefit of in-flight air exchange*, so it’s likely higher risk during those times than in the air during the middle of the flight, even if CO2 levels are equally high during flight.

Indoor spaces like grocery stores or conference rooms/meeting halls

Indoor spaces can vary quite a bit, and often by country or venue.

For example, most indoor spaces in the US we’ve found to often have a fairly high (e.g. 900+ ppm) indoor CO2 level, even without a huge density of people. For example, we quickly went into a grocery store the other day and the CO2 was high-800s without being around many people in the aisles, across the entire store. For not having people actively occupying the space, this is fairly high and less optimal.

In contrast, we recently were in Sweden for a conference and were honestly gobsmacked when we got off the plane and found the CO2 levels to be <600 ppm in the airport! And in the hotel lobby! And in the hotel elevator! And at the local grocery store!

(Seriously, it shocked us, because we’ve also recently been in the UK with our CO2 monitor and found US-like CO2 levels typically around 900-1000 ppm or higher, and also in Spain last year where we similarly found it to be >900 ppm even when not densely occupied. The exception to optimal air quality in Sweden was our ~20 minute bus ride where CO2 levels were >2500 ppm).

So, the CO2 levels may vary quite a bit and this is why measuring is helpful. Because you can’t assume that one country/one room means that all of the rooms in that country or even that venue will be the same.

Case in point? Conference rooms/halls or meeting rooms.

In Barcelona, Spain in April 2022, I spoke at a conference. The CO2 levels in the hallways and in the meeting room before the session started were around 800-900 ppm when not occupied. Again, a little high for not having people actively in the spaces. Then, when the conference started, Scott watched the CO2 monitor and saw it rise..and rise…and rise. Within 45 minutes, the CO2 levels were around 2000 ppm (>1500 ppm over outdoor air quality)! He went to the back of the room and opened the doors to try to get some air circulating in the room, although it didn’t make a big difference. That room did not have a high number of air exchanges per hour and was not successfully clearing out the air people were breathing out.

In Sweden (May 2023, where the CO2 was <600 in a lot of public indoor spaces), we found the same challenge in a high ceiling, large meeting hall. With 300 people, the start of the session had about 950 ppm (as opposed to the <600 ppm of less occupied hallways). Not too bad given 300 people in the space. However, by the end of the session, the CO2 level had risen to ~1350! And it continued to rise even as people had exited the room; we didn’t see a drop in CO2 levels until we went out in the hallway to continue talking to people, and it took another ~25 minutes before CO2 levels in the hallway were back down <600 ppm.

Again, we were surprised, because this venue (the hallways, lobby, elevator, etc) all had really great otherwise indoor air quality with CO2 <600 ppm!

But the challenge is the space (and the infrastructure for filtration and air exchanges); the number of people filling the space; and the amount of time, in terms of what happens to the CO2 levels.

The takeaway from this? Conference halls, meeting rooms, and anywhere where you are sitting with a group of people over a period of time is going to have a much higher CO2 level and it will increase in proportion to the time that you are occupying that space (e.g. a 30 minute or 1 hour session is going to have a much higher CO2 buildup than a 10 minute talk where the audience is turning over and leaving the room and it clears out some before the next session).

So what should you do about this information? Consider situational masking.

I really have found a CO2 monitor helpful, because even my best guesses about air quality (e.g. thinking Sweden’s conference hall would have good air quality given the size of the room and ceilings) aren’t always accurate. But if you don’t want to invest in a CO2 monitor, here’s where you can get the biggest bang for your buck with situational masking.

What do I mean by situational masking? Maybe you don’t think you’re at very high risk for COVID or other infectious illnesses, but you are interested in reducing the likelihood that you spread anything you get to other people (thanks!). But you don’t want to have to think about it, and maybe you’ve chosen previously to drop masking so you don’t have to think about it. Here’s a set of easy rules/situations in which, like learning to dump your liquids out before going through airport security, you can get into a habit of doing and not have to think about it much.

  • Public/shared transportation.

    Riding a bus, train, metro, or a car with a stranger and especially with multiple strangers – these have high CO2 levels.

  • Airports, boarding a plane and during takeoff, and during descent/landing/deboarding the plane.

    This is when the CO2 levels are highest and the air exchanges/HEPA filtration is not running.

    Think of it like the seatbelt sign. You board the plane and put your seatbelt on, then eventually once you’ve reached cruising altitude the seatbelt sign goes off. If you’re standing in a line of people (to board or deplane) OR if the seatbelt sign is ON, that’s a huge ROI for wearing a high-quality (N95 or KN95) mask. When the seatbelt sign first turns off during the flight (or you hear the 10k-feet chime) and you want to take and leave it off, or take it off a while to eat or drink – that’s less risky during those times due to the HEPA filtration and air exchanges during flight. But when the seatbelt sign goes on for the plane’s final descent? The air quality is going down, too, so putting your seatbelt AND your mask back on is a higher ROI thing to do.

    (You do you inside the airport, too, but see below about density of people and temperature as a guide for whether you might want to consider situational masking in airports when you’re not eating/drinking.)

 

  • Conferences or meetings where you are sitting for more than a few minutes and there are many people in the room.

    Even with super big rooms and super high ceilings, so far every conference space I’ve presented in during the last several years has high CO2 levels even before the talk starts, and is even higher (>500-1000 ppm added) by the end of the session). If you’re not presenting or eating and drinking and are just sitting there listening and engaging in the session…it’s a low hassle opportunity to pop a high-quality mask on so you’re not breathing so much of the air around you from everyone else. When you’re done with the session and head out and want to socialize? Like leaving the plane, you’ll be around fewer people, and the CO2 levels (and risk) goes down. But sitting there quietly is a great time to wear a good mask and reduce your intake of other people’s exhalations.

 

You might find yourself in situations where the room feels hot and stuffy, or in the case of conferences and meetings, the air feels FREEZING cold. It runs freezing cold because the room gets hot and stuffy with so many people, indicating this space is not well ventilated, so they pump the AC to change the temperature. But that is a compensation for a too-low rate of air exchanges, and pre-cooling doesn’t prevent CO2 and aerosol buildup, so a room that either gets freezing cold or hot and stuffy should be a signal that the air quality likely isn’t ideal.

So a good rule of thumb is, if you’re in a space that feels hot and stuffy OR freezing cold, that’s an indicator that the air quality might be non-optimal. Consider masking in those situations even if you don’t have a CO2 monitor to evaluate the air.

It would be great if we could get 10x people to consider situational masking like this. Avoid the worst of the bad-news-bear-air of public and shared transportation and indoor spaces, which would cut down on a lot of transmission, even if people otherwise are still socializing and eating in indoor spaces and doing whatever it is they want to do. The choice to situationally mask might occasionally protect them but would also protect everyone around them in those situations when their exhalations have the greatest risk of doing the most damage.

A good way to think about it is at a conference. You might be willing to go to bars and socialize, but someone who is higher risk may be choosing not to attend those indoor dining scenarios. That’s fine: you each get to make your own choices! But when you go and sit down next to that person in a conference session, your choices then influence that person by every breath you take in that conference session.

That’s why situational masking – knowing that a situation is low-hassle to wear a high-quality mask (sitting quietly in a session) but high-risk (due to the poor air quality) means you have a high ROI to pull a mask out of your pocket/bag and throw it on – can help the people around you very effectively with little hassle and thought on your part.

You can get in the habit of masking in the bad-news-bear-air situations/locations, and you don’t have to think much about it. You’ll make things a bit safer for yourself and for the people around you, for far less hassle than avoiding buying a drink before you go through airport security because you know you need to dump liquids out.

Data-driven situational masking based on indoor air quality

How To Talk To Your Doctor About Your Enzyme (PERT) Dosing If You Have Exocrine Pancreatic Insufficiency (EPI or PEI or PI)

In exocrine pancreatic insufficiency (EPI/PEI/PI), people are responsible for self-dosing their medication every time they eat something.

Doctors prescribe a starting dose, but a person with EPI determines each and every time they eat or drink something how many enzyme pills (of pancreatic enzyme replacement therapy, known as PERT) to take. Doctors often prescribe a low starting dose, and people have to try experimenting with multiple pills of the small size, and eventually work with their doctors to change their prescription to get a bigger pill size (so they can take fewer pills per meal) and the correct number of pills per day to match their needs.

For example, often people are prescribed one 10,000 unit pill per meal. The 10,000 units represents the amount of lipase (to help digest fat). There are also two other enzymes (protease, for protein digestion, and amylase, for carbohydrate digestion). They may be prescribed 1 pill per meal, which means 10,000 units of lipase per meal. But most dosing guidelines recommend starting at a dose of 40,000-50,000 units of lipase per meal (and people often need more), so it wouldn’t be surprising that someone prescribed one 10,000 pill per meal would need 4-5 pills of the 10,000 size pill PER MEAL, and times three meals per day (let alone any snacks), to get acceptable GI outcomes.

Mathematically, this means the initial prescription wouldn’t last long. The initial prescription for 1 pill per meal, with 3 meals a day, means 3 pills per day. 3 pills per day across a 30 day month is 90 pills. But when the pills per meal increase, that means the prescription won’t cover the entire month.

In fact, it would last a lot less than a month; closer to one week!

Showing that based on the number of pills and 3 meals per day, an intitial RX of 10,000 size pills may last more like a week rather than a full 30 days when the doctor is unaware of prescribing guidlines that typically suggest 40,000-50,000 per meal is needed as the starting meal dose.

Let’s repeat: with a too-small prescription pill size (e.g. 10,000 starting dose size) and count (e.g. 3 pills per day to cover 1 per meal) and with a person with EPI titrating themselves up to the starting dose guidelines in all of the medical literature, they would run out of their prescription WITHIN ONE WEEK. 

So. If you have EPI, you need to be prepared to adjust your dosing yourself; but you also need to be ready to reach out to your doctor and talk about your need for more enzymes and a changed prescription.

PERT (enzymes) come in different sizes, so one option is to ask for a bigger pill size and/or a different amount (count) per meal/day. Depending on the brand and the number of pills you need per meal, it could be simply going up to a bigger pill size. For example, if you need 3 pills of the 10,000 PERT size, you could move to a 36,000 pill size and take one per meal. If you find yourself taking 5 pills of the 10,000 PERT size, that might mean 2 pills of the 25,000 size. (Brands differ slightly, e.g. one might be 24,000 instead of 25,000, so the math may work out slightly differently depending on which brand you’re taking.)

Don’t be surprised if you need to do this within a week or two of starting PERT. In fact, based on the math above, especially if you’re on a much lower dose than starting guidelines (e.g. 40,000-50,000 units of lipase per meal), you should expect within a few days to need an updated prescription to make sure that you don’t run out of PERT.

If you do find yourself running out of PERT before you can get your prescription updated, there is an alternative you can consider: either substituting or adding on over the counter enzymes. The downsides include the fact that insurance doesn’t cover them so you would be paying out of pocket; plus there are no studies with these so you can’t (shouldn’t) rely on these as full 1:1 substitutes for prescription PERT without careful personal testing that you can do so. That being said, there is anecdotal evidence (from me, as well as hundreds of other people I’ve seen in community groups) that it is possible to use OTC enzymes if you can’t afford or can’t get a PERT prescription; or if you need to “top off”/supplement/add to your PERT because your prescription won’t last a full month and you can’t get a hold of your doctor or they won’t update your prescription.

For me, I generally evaluate the units of lipase (e.g. this kind is 17,000 units of lipase per pill) but then factor in for the lack of reliability for OTC and really treat it like it contains 13-15,000 units of lipase when choosing to take it. Similarly for another lipase-only OTC option (that has ~6,000 units per pill), I assume it acts like it only has ~5,000 units. Unlike insulin, there is little downside to taking a little too much of enzymes; but there is a LOT of downside to not taking enough, so my personal approach is that if in doubt, or on the fence, to round up (especially with OTC pills, which cost somewhere between $0.08/pill (lipase-only) to $0.34/pill (for the larger and multiple enzyme pill)).

So how do you talk to your doctor about needing more PERT?

It helps if you bring data and evidence to the conversation, especially if your doctor thinks by default that you don’t need more than what they initially prescribed. You can bring your personal data (more on that below and how to collect and present that), but you can also cite relevant medical literature to show if your dose is below standard starting guidelines.

Below I’ve shared a series of citations that show that the typical starting dose for people with EPI should be around 40,000-50,000 units of lipase per meal.

Important note that this is the STARTING DOSE SIZE, and most of these recommend further increasing of dose to 2-3 times this amount as needed. Depending on the starting dose size, you can see the chart I built below that illustrates with examples exactly how much this means one might need to increase to. Not everyone will need the upper end of the numbers, but if a doctor starts someone on 10,000 and doesn’t want to get them up to 40,000 (the lower end of starting doses) or go beyond 40,000 because it’s the starting dose, I’ve found this chart useful to show that numerically the range is a lot larger than we might assume.

Example of Titrating According to Common Dose Guidelines, Before Adding PPI

Examples of PERT starting doses of 25,000, 40,000, and 50,000 (plus half that for snacks) and what the dose would be if increased according to guidelines to 2x and 3x, plus the sum of the total daily dose needed at those levels.

Here are some citations that back up my point about 40,000-50,000 units of lipase being the typically recommended starting dose, including across different conditions (e.g. regardless of whether you have EPI + any of (chronic pancreatitis, diabetes, celiac, etc)).

  • Shandro et al, 2020, the median starting dose of 50,000 units per lipase “is an appropriate starting dose”, also citing UEG 2017 guidelines.
  • Forsmark et al, 2020, defined appropriate dose of PERT as >=120,000 units of lipase per day (e.g. 40,000 units of lipase per meal).
  • Whitcomb et al, 2022, in a joint American Gastroenterology Association and PancreasFest symposium paper, concur on 40,000 units as a starting dose and that “This dose should be titrated up as needed to reduce steatorrhea or gastrointestinal symptoms of maldigestion “
  • 2021 UK guidelines for EPI management suggest 50,000 units as the starting dose and emphasize that “all guidelines endorse dose escalation if the initial dose is not effective”

There are also many guidelines and research specific for EPI and different co-conditions supporting the ballpark of 40-50,000 units of lipase starting dose:

It is also worth noting that these guidelines also point out that after titrating 2-3x above the starting dose, PPI (proton pump inhibitors, to suppress acid) should be added if gastrointestinal symptoms are still not resolved. Anecdotally, it seems a lot of doctors are not aware that PPIs should be added if 3x the starting dose is not effective, so make sure to bring this up as well.

How to Share Your Personal PERT Data To Show How Much You Need

In addition to pointing out the guidelines (based on the above), it’s useful to share your data to show what you’ve been taking (dosing) and how it’s been working. I’ve written a lot about how you can do this manually, but I also recently created an iOS based app to make it easier to track what you’re eating, what you’re dosing in terms of PERT/enzymes, and what the outcome is. This app, PERT Pilot, is free to use, and it also enables you to visualize on a graph the relationship between what you’re eating and dosing.

PERT Pilot lets you track how many grams of fat each pill of your current prescription has been used for, so you can see with red and green coloring the relationship between meals that you’ve had symptoms after (in red) vs. when you recorded no symptoms (green). If you have a “convergence zone” of green and red in the same area, that may help you decide to change your ratio (e.g. dose more) around that amount, until you can comfortably and repeatedly get green results (no symptoms when you eat).

How you might use this to talk to your doctor

You can take a screenshot of your PERT Pilot graph and share it with your doctor to show them how many grams of fat your prescription size (e.g. pill size) effectively “covers” for you, and how many meals that you’ve tested it with.

Meals based on the ratio of fat:lipase and protein:protease mapped with color coded dots where green means no symptoms, orange means not sure if symptoms, and red means symptoms occurred and the dose likely didn't work at that ratio.For example, I was initially prescribed an enzyme dose that was one pill per meal (and no snacks), so I had 3 pills per day. But I quickly found myself needing two pills per meal, based on what I was typically eating. I summarized my data to my doctor, saying that I found one pill typically covered up to ~30 grams of fat per meal, but most of my meals were >30 grams of fat, so that I wanted to update my prescription to have an average of 2 pills per meal of this prescription size. I also wanted to be able to eat snacks, so I asked for 2 pills per meal, 1 per snack, which meant that my prescription increased to 8 pills per day (of the same size), to cover 2 pills x 3 meals a day (=6) plus up to 2 snacks (=2). I also had weeks of data to show that my average meal was >30 grams of fat to confirm that I need more than the amount of lipase I was originally prescribed. My doctor was happy to increase my prescription as a result, and this is what I’ve been using successfully for over a year ever since.

So in summary, the data that would be useful to share is:

  • How much one pill ‘covers’ (which is where the PERT Pilot graph can be used)
  • How many pills per meal you’ve been taking and how big your meals typically are
  • Whether you are struggling with the number of pills per meal: if so, ask whether there’s a larger pill size in your current brand that you could increase to, in order to reduce the number of pills per meal (and/or snack) you need to take every time

If you are told that you shouldn’t need “that much”, remember the above section and have those resources ready to discuss that the starting dose is often 40,000-50,000 per meal and that the guidelines say to titrate up to 3x that before adding PPI. Therefore, it would be expected for some people to need upwards of 600,000 units of lipase per day (50,000 starting dose, increased 3x per meal and half of the dose used per snack). Depending on what people eat, this could be even higher (because not everyone eats the same size meal and snack and many of us adjust dose based on what we eat).

Also, it is worth noting that the dosing guidelines never mention the elastase levels or severity of EPI: so PERT prescriptions should not be based on whether you have “moderate” or “severe” EPI and what your elastase level is (e.g. whether it’s 45 or 102 or 146 or even 200, right on the line of EPI – all of those elastase levels would still get the same starting dose of PERT, based on the clinical guidelines for EPI).

It is common and you are not alone if you’ve not been giving the starting dose of PERT that the guidelines recommend.

There are numerous studies showing most people with EPI are initially underdosed/underprescribed PERT. For example, in 2020 Forsmark et al reported that only 8.5% of people with chronic pancreatitis and EPI received an adequate prescription for PERT: and only 5.5% of people with pancreatic cancer and EPI received an adequate prescription dose of PERT. Other studies in chronic pancreatitis and EPI from 2014, 2016, and 2020 report that undertreatment often occurs in EPI and CP; and I’ve found studies in other conditions as well showing undertreatment compared to guidelines, although it’s most studied in CP and cancer (which is true of all types of EPI-related research, despite the prevalence in many other conditions like diabetes, celiac, etc.).

You may need to advocate for yourself, but know that you’re not alone. Again, feel free to comment or email privately (Dana@OpenAPS.org) if you need help finding research for another co-condition and EPI that I haven’t mentioned here.

PS – if you haven’t seen it, I have other posts about EPI at DIYPS.org/EPI


You can also contribute to a research study and help us learn more about EPI/PEI – take this anonymous survey to share your experiences with EPI-related symptoms!

How I Built An AI Meal Estimation App – AI Meal Estimates in “PERT Pilot” and Announcing A New App “Carb Pilot”

As I have been working on adding additional features to PERT Pilot, the app I built (now available on the App Store for iOS!) for people like me who are living with exocrine pancreatic insufficiency, I’ve been thinking about all the things that have been challenging with managing pancreatic enzyme replacement therapy (PERT). One of those things was estimating the macronutrients – meaning grams of fat and protein and carb – in what I was eating.

I have 20+ years practice on estimating carbs, but when I was diagnosed with EPI, estimating fat and protein was challenging! I figured out methods that worked for me, but part of my PERT Pilot work has included re-thinking some of my assumptions about what is “fine” and what would be a lot better if I could improve things. And honestly, food estimation is still one of those things I wanted to improve! Not so much the accuracy (for me, after a year+ of practice I feel as though I have the hang of it), but the BURDEN of work it takes to develop those estimates. It’s a lot of work and part of the reason it feels hard to titrate PERT every single time I want to eat something.

So I thought to myself, wouldn’t it be nice if we could use AI tools to get back quick estimates of fat, protein, and carbs automatically in the app? Then we could edit them or otherwise use those estimates.

And so after getting the initial version of PERT Pilot approved and in the App Store for users to start using, I submitted another update – this time with meal estimation! It’s now been live for over a week.

Here’s how it works:

  • Give your meal a short title (which is not used by the AI but is used at a glance by us humans to see the meal in your list of saved meals).
  • Write a simple description of what you’re planning to eat. It can be short (e.g. “hot dogs”) or with a bit more detail (e.g. “two hot dogs with gluten free buns and lots of shredded cheddar cheese”). A little more detail will get you a somewhat more accurate estimates.
  • Hit submit, and then review the generated list of estimated counts. You can edit them if you think they’re not quite right, and then save them.

Here’s a preview of the feature as a video. I also asked friends for examples of what they’d serve if they had friends or family coming over to dinner – check out the meal descriptions and the counts the app generated for them. (This is exactly how I have been using the app when traveling and eating takeout or eating at someone’s house.)

Showing screenshots of PERT Pilot with the meal description input and the output of the estimated macronutrient counts for grams of fat, protein, and carb Showing more screenshots of PERT Pilot with the meal description input and the output of the estimated macronutrient counts for grams of fat, protein, and carb Showing even more screenshots of PERT Pilot with the meal description input and the output of the estimated macronutrient counts for grams of fat, protein, and carb

The original intent of this was to aid people with EPI (PEI/PI) in estimating what they’re eating so they can better match the needed enzyme dosing to it. But I realized…there’s probably a lot of other people who might like a meal estimation app, too. Particularly those of us who are using carb counts to dose insulin several times a day!

I pulled the AI meal estimation idea out into a second, separate app called Carb Pilot, which is also now available on the App Store.

Carb Pilot is designed to make carb counting easier and to save a bunch of clicks for getting an estimate for what you’re eating.

The Carb Pilot logo, which has pieces of fruit on the letters of the word "Carb". Pilot is written in italic script in purple font.

What does Carb Pilot do?

  • Like PERT Pilot, Carb Pilot has the AI meal estimation feature. You can click the button, type your meal description (and a meal title) and get back AI-generated estimates.
  • You can also use voice entry and quickly, verbally describe your meal.
  • You can also enter/save a meal manually, if you know what the counts are, or want to make your own estimates.

Carb Pilot integrates with HealthKit, so if you want, you can enable that and save any/all of your macronutrients there. HealthKit is a great tool for then porting your data to other apps where you might want to see this data along with, say, your favorite diabetes app that contains CGM/glucose data (or for any other reason/combination).

Speaking of “any/all”, Carb Pilot is designed to be different from other food tracking apps.

As a person with diabetes, historically I *just* wanted carb counts. I didn’t want to have to sift through a zillion other numbers when I just needed ONE piece of information. If that’s true for you – whether it’s carbs, protein, calories, or fat – during onboarding you can choose which of these macronutrients you want to display.

Just want to see carbs? That’s the default, and then in the saved meals you’ll ONLY see the carb info! If you change your mind, you can always change this in the Settings menu, and then the additional macronutrients will be displayed again.

Carb Pilot enables you to toggle the display of different nutrients. This shows what it looks like if only carbs are displaying or what happens if you ask the app to display all nutrients for each recorded food item.

It’s been really fun to build out Carb Pilot. Scott has been my tester for it, and interestingly, he’s turned into a super user of Carb Pilot because, in his words, “it’s so easy to use” and to generate macronutrient estimates for what he’s eating. (His use case isn’t for dosing medicine but matching what he’s eating against his energy expenditure for how much exercise/activity he’s been doing.) He’s been using it and giving me feedback and feature requests – I ended up building the voice-entry feature much more quickly than I expected because he was very interested in using it, which has been great! He also requested the ability to display meals in reverse chronological order and to be able to copy a previous meal to repeat it on another day (swipe on a meal and you can copy the description if you want to tweak and use it again, or simply repeat the meal as-is). We also discovered that it supports multiple languages as input for the AI meal estimation feature. How? Well, we were eating outside at a restaurant in Sweden and Scott copied and pasted the entree description from the menu – in Swedish – into Carb Pilot. It returned the counts for the meal, exactly as if he had entered them in English (our default language)!

I’m pointing this out because if you give Carb Pilot a try and have an idea for a feature/wish you could change the app in some way, I would LOVE for you to email me and tell me about it. I have a few other improvements I’m already planning to add but I’d love to make this as useful to as many people who would find this type of app helpful.

Why (was) there a subscription for ongoing AI use?

For both PERT Pilot and Carb Pilot, there is a cost (expense) to using the AI meal estimation. I have to pay OpenAI (which hosts the AI I’m using for the app) to use the AI for each meal estimation, and I have to host a web server to communicate between the app and the AI, which also costs a bit for every time we send a meal estimation request from the app. That’s why I decided to make Carb Pilot free to download and try. I originally played with $1.99 a month for unlimited AI meal estimations, but temporarily have turned that off to see what that does to the server load and cost, so right now it’s free to use the AI features as well.

TLDR:

– PERT Pilot has been updated to include the new meal estimation feature!

– People without EPI can use Carb Pilot for carb, protein, fat, and/or calorie tracking (of just one or any selection of those) tracking, also using the new AI meal estimation features!

You can find PERT Pilot here or Carb Pilot here on the App Store.

PERT Pilot – the first iOS app for Exocrine Pancreatic Insufficiency (EPI or PEI) and Pancreatic Enzyme Replacement Therapy (PERT)

Introducing PERT Pilot, the first iOS app designed for people with exocrine pancreatic insufficiency (EPI / PEI) and the only iOS app for specifically recording pancreatic enzyme replacement therapy (PERT) dosing!

*Available to download for FREE on the iOS App Store *
The PERT Pilot logo - PERT is in all caps and bold purple font, the word "Pilot" is in a script font in black placed below PERT.

After originally developing GI symptoms, then working through the long journey to diagnosis with exocrine pancreatic insufficiency (known as EPI or PEI), I’ve had to come up methods to figure out the right dosing of PERT for my EPI. I realized that the methods that I’ve made work for me – logging what I was eating in a spreadsheet and using it to determine the ratios I needed to use to dose my pancreatic enzyme replacement therapy (PERT) – weren’t methods that other people were as comfortable using. I have been thinking about this for the last year or more, and in my pursuit for wanting to encourage others to improve their outcomes with EPI (and realize that it IS possible to get to few symptoms, based on increasing/titrating the enzymes we take based on what we eat), I wrote a very long blog post explaining these methods and also sharing a free web-based calculator to help others to calculate their ratios.

But, that still isn’t the most user-friendly way to enable people to do this.

What else could I do, though? I wasn’t sure.

More recently, though, I have been experimenting with various projects and using ‘large language model’ (LLM) tools like GPT-4 to work on various projects. And a few weeks ago I realized that maybe I could *try* to build an iOS app version of my idea. I wanted something to help people log what they are eating, record their PERT dosing, and more easily see the relationship in what they are eating and what enzymes they are dosing. This would enable them to use that information to more easily adjust what they are dosing for future meals if they’re not (yet) satisfied with their outcomes.

And thus, PERT Pilot was born!

Screenshots from the PERT Pilot app which show the home screen, the calculator where you enter what PERT you're taking and a typical meal, plus the resulting ratios screen that show you the relationship between what you ate and how many enzymes you dosed.

What does PERT Pilot do?

PERT Pilot is designed to help people living with Exocrine Pancreatic Insufficiency (EPI or PEI) more easily deal with pancreatic enzyme replacement therapy (PERT). Aka, “taking enzymes”.

The PERT Pilot calculator enables you log the PERT that you are taking along with a meal, how many pills you take for it, and whether this dosing seems to work for you or not.

PERT Pilot then shows you the relationship between how much PERT you have been taking and what you are eating, supporting you as you fine-tune your enzyme intake.

PERT Pilot also enables you to share what’s working – and what might not be working – with your healthcare provider. PERT Pilot not only lists every meal you’ve entered, but also has a visual graph so you can see each meal and how much fat and protein from each meal were dosed by one pill – and it’s color coded by the outcome you assigned that meal! Green means you said that meal’s dosing “worked”; orange means you were “unsure”, and red matches the meals you said “didn’t work” for that level of dosing.

You can press on any meal and edit it, and you can swipe to delete a meal.

PERT Pilot also has is an education section so you can learn more about EPI and why you need PERT, and how this approach to ratios may help you more effectively dose your PERT in the future.

Why use PERT Pilot if you have EPI or PEI or PI?

PERT Pilot is the first and only specific app for those of us living with EPI (PEI or PI). People who use the approach in PERT Pilot of adapting their PERT dosing to what they are eating for each meal or snack often report fewer symptoms. PERT Pilot was designed and built by someone with exocrine pancreatic insufficiency, just like you!

With PERT Pilot you can:

  • Log your meals and PERT dosing. No other app specifically is designed for PERT dosing.
  • Edit or adjust your meal entry at any time – including if you wake up the next morning and realize your last dose from the day before ‘didn’t work’.
  • Review your dosing and see all of your meals, dosing, and outcomes – including a visual graph that shows you, for each meal, what one pill ‘covered’ so you can see where there are clusters of dosing that worked and if there are any clear patterns in what didn’t work for you.
  • You can also export your data, as a PDF list of all meals or a CSV file (which you can open in tools like Excel or other spreadsheet tools) if you want to analyze your data elsewhere!
  • Your data is your data, period. No one has access to your dosing data, meal data, or outcome data, and nothing you enter into PERT Pilot leaves your device – unless you decide to export your data. (See more in the PERT Pilot Privacy Policy.)

Note: this app was not funded by nor has any relationship to any pharmaceutical or medical-related companies. It’s simply built by a person with EPI for other people with EPI.

Here is a quick demonstration of PERT Pilot in action:

An animated gif of PERT Pilot in action

You can share your feedback about PERT Pilot:

Feel free to email me (Dana+PERTPilot@OpenAPS.org) any time.

I’d love to hear what works or is helpful, but also if something in the app isn’t yet working as expected.

Or, if you use another approved brand of PERT that’s not currently listed, let me know and I can add it in.

And, you can share your feature requests! I’m planning to build more features soon (see below).

What’s coming next for PERT Pilot:

I’m not done improving the functionality! I plan to add an AI meal estimation feature (UPDATE: now available!), so if you don’t know what’s in what you’re eating at a restaurant or someone else’s home cooked meal you can simply enter a description of the meal and have macronutrient estimates generated for you to use or modify.

Download PERT Pilot today! It’s free to download, so go ahead and download it and check it out! If you find it useful, please also leave a rating or review on the App Store to help other people find it in the future. You can also share it via social media, and give people a link to download it: https://bit.ly/PERT-Pilot-iOS