How to do “eating soon” mode – #DIYPS lessons learned

“Do you prebolus for meals with #DIYPS?”

The answer to this question is complicated for me. I don’t “prebolus” like most people do (meaning “take some or all of your meal insulin about 15 minutes before you eat”).

I do take insulin before a meal. In fact, I do it up to an hour before the meal starts, by setting my correction target BG from it’s usual range (usually 100-120) to 80. This usually means I’m usually doing anywhere from .5-1u or more of insulin prior to a meal. But the amount of insulin has no direct relationship with the total amount of carbs I’ll end up eating during the meal.

Does it work? Yes. Do I go low? No, because it is unlikely that I would get anywhere near 80 by the time my carbs kick in for a meal (15 minutes after I eat), and therefore the initial carbs are handled by that initial amount of insulin from the eating soon-bolus. (Last year, I wrote a post about “eating soon mode” under the guise of lessons learned about meal time with #DIYPS – if you want to read the reason behind WHY eating soon mode is key in more detail, you can definitely read the longer version of the post. It also links another key concept I’ve learned about called carbohydrate absorption rate.)

So, how can you manually do “eating soon” mode?

1. If you know you’re going to eat anywhere in the next hour, manually calculate a correction bolus with a target BG of 80. (Example – if your correction ratio is 1:40, and you are currently 120, that means you would give yourself 1u of insulin.) An hour, 45 minutes, 30 minutes – whatever you make work is better than not doing it!

2. Eat your meal and bolus normally, but use your IOB as part of your meal calculation so you don’t forget about that insulin you already have going. (Helpful if your pump tracks IOB and you use a bolus calculator feature, but if you take injections, keep in mind about the insulin you’ve already given for the meal – just subtract that amount (1u in above example) from what you’d otherwise inject for the meal.

Note: if you use eating soon mode, you might want to delay the last unit or two of your meal insulin until after you see BGs rise, since sometimes you need less total insulin for the meal if you get insulin active early. (Often, we PWDs may overcompensate with more insulin than we need because it’s not timed correctly compared to the carb absorption rate.)


  • 5pm – You’re planning to eat around 5:30 or 6pm. Your BG is 120 and your correction ratio is 1:40. Setting your correction target to 80, that means you take 1u of insulin.
  • 6pm – You sit down to eat. Looking at your meal, you see 45 carbs and decide, with a carb ratio of 1:10, that you would take 4.5 units for the meal. Keeping in mind your earlier bolus of 1u, you end up taking 3.5 units for the meal. (4.5 total – 1u prebolus = 3.5 more units needed to cover the meal, see above note about considering delaying a unit or two of that bolus until you see your BGs impacted by carbs).

Result? You should have less of a spike from your carbs kicking in 15 minutes after you eat. It won’t always completely eliminate a spike, but it will provide a flattening effect. This is part of how I’m able to eat large (like 120g of gluten free pizza) meals and have flat or mostly flat BGs, and this is also one of the reasons I think using #DIYPS has dramatically improved my eAG and a1cs.

10 thoughts on “How to do “eating soon” mode – #DIYPS lessons learned

  1. “I’m able to eat large (like 120g of gluten free pizza) meals and have flat or mostly flat BGs”

    120 grams of pizza, or 120 grams of carb?

  2. Hi Dana,

    Just wanted to let you know that I started experimenting-testing “eating sooon” mode and it is working great :)

    Thank you so much for all the pointers on how to inplement it.
    I will be moving to 0ref1 in the next few weeks. Exciting!

    Million Thanks :)

  3. Hello, I have a question, not sure if I’ll word it right and I think it will probably reveal a misunderstanding in my part. If my dd BG is 160 with ISF 40 as your example, she should take 1.5 units to bring her down to 80 and take 1.5 units off her meal bolus when she eats an hour later? However, does she not need the part of the correction that would bring her down to her usual target (100) anyway? Why do you take the whole correction off the meal bolus and not just the difference between the usual target and the eating soon target? Thanks for providing all this info on OpenAPS, it’s so interesting.

    1. We assumed that you (or your closed loop) would have already corrected down to 100 prior to doing your eating soon bolus. If you want to do it all together, then you are correct that you’d only need to subtract the extra correction (from 100 down to 80) off the meal bolus.

  4. I am looping with OpenAPS (10 days : )!). How do I set a temp target for “eating soon mode” without changing it manually in the pump’s bolus settings? I have Nightscout with careportal, but do not see any option to change the target on my Nightscout site. What am I missing to be able to do this? Thanks in advance!

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