Insulin Stacking

MY endo ( who most of you know by now that i consider to be an imbecile) has told me that i should not bolus before 2 hours after i have finished eating my last meal, snack or whatever. so, if i am eating dinner, but still feel hungry afterwards, i should not re-bolus for more food. now this seems ridiculous to me. what if i decide i do want some desert or some coffee after my meal? cant i just bolus and continue eating?

when is it considered insulin stacking, and what is insulin stacking? and, how would you avoide insulin stacking if it is indeed bad for you?

all suggestions welcome :blush:

Here is the idea behind insulin stacking…

You know how your insulin lasts several hours? Maybe it takes 4 hours before your bolus is completely gone. Most of it gets used in the first 60-90 minutes, but some of it is still trickling through your body for a total of 4 or 5 hours.

Suppose you take insulin for your meal, and then an hour later you want to eat more, so you take more insulin.

The endo is worried that you will still have insulin from your first bolus, and the second bolus will add to the first bolus with the total amount of insulin, the IOB you still have. That is called “stacking”.

So if you were a new diabetic, and you didn’t know what you were doing, he would tell you to not stack, because the second dose would get added to some of the first. The second bolus would add to your IOB, and you might go low.

But…you know what you are doing! You test a lot. You pay attention to your numbers. You are not a new diabetic!

If you calculate the first bolus correctly, and you want to add more food later, of course you should take more insulin for that.

Keep in mind, your IC ratios might be different if you have a bit of insulin left over from the first bolus. You may need a bit less insulin for the food you eat later, just because of the leftover insulin.

For someone like you, with your experience, this is just silliness. If you want to eat a little more later, of course you can take insulin for that. Just pay attention to possibly different IC ratios, test, and pay attention to your BG.


I agree with @Eric. Insulin stacking is probably not recommended to the novice or those that do not manage as stringently. As long as you have a way of keeping track of your boluses, I think it is fine. The hard part is that active insulin takes time to ramp up and down–so having multiple boluses with varying insulin peaks could get confusing really fast.

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My general approach to insulin dosing/stacking.

Always dose for food.

Always dose for BG correction if no previous bolus within 3 hrs.

Fine tune it from there.

Not bolusing for a 35 carb desert after finishing dinner seems crazy advice from a medical professional.

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Insulin stacking is a key part of how I deal with higher carb meals when I do eat them, especially since it’s hard to predict exactly how much you’ll eat until you actually eat. So I will use the technique I mentioned in the vacation thread (mentioned there since I use it constantly when on vacation and eating out, and less often at home), where I estimate the likely range of carbs to be consumed at the upcoming meal, pre-bolus for the lower end, and dose as or after I eat for any extra beyond that. Usually that results in a mild spike (vs prebolusing for everything), but way better than if I waited until I knew for sure what I was eating (which is the only way I can figure to do that without stacking insulin).

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i’ll use an example from yesterday:

dinner time was coming soon. i had no IOB from my previous bolus from lunchtime. it is 5pm and i have a terrible tummy ache from bloating/reflux, etc. i want to take a TUMS, which i need to bolus for. but i know that i will be eating dinner in 1.5 hours and then i will have to re-bolus. do i ignore the discomfort and take the TUMS when it is time for dinner?
how do i navigate this situation?

do i use my Pump’s WIZARD feature at dinner time if i had bolused for the TUMS? will that take care of accounting for the previous bolus and IOB? it seems like it would. not certain.

still a bit confused.

What I would do:

I would check BG at 5PM.
Bolus for BG correction (if required) and bolus for the carbs for the TUMS all together at 5PM.

At 6:30 PM don’t bother checking BG again. Bolus for the dinner carbs. Ignore insulin-on-board from previous bolus.

At 9:30 PM check BG and see how it all worked out. Maybe bolus for BG or not depending on where the BG is and what type of food (carb/protein/fat amounts) and when going to sleep and what not.

why dont bother checking BG again? what if i’ve gone high or low? shouldnt i know that before bolusing for my meal?

Your 5:00 PM check for BG should take care of it.

IMHO the idea around NOT insulin stacking is NOT checking and correcting for BG in a time interval too short for such corrections to be implemented. Checking and correcting for BG at both 5:00 PM and 6:30 PM is (in general) too close together and WOULD be improper insulin stacking. For the most part. For most situations. In my opinion.

So in that respect, I would agree with the Endo. But taking THAT concept and extending it to NOT bolus for additional food is (again my opinion) completely crap and mixing different issues.

I am not sure about the way Medtronic calculates their meal boluses and IOB. Different pumps do it differently. Some pumps subtract current IOB from the bolus count you are about to do. Some pumps only look at carbs and BG.

But how much do you bolus for TUMS? I think that would be a small amount, and wouldn’t be much of a factor.

I would suggest you check your BG and then take what you need for the TUMS, and at dinner time, check your BG again and take what you need for dinner. In this case, don’t worry about stacking.

And if the WIZARD is messing you up, remember, anything you give yourself with a pen or syringe…the WIZARD will never know about… :wink:

i only need to count for 6 gms for 2 tums. so its really not that big of a deal.

my Wizard feature takes into account for the insulin that is still active and it subtracts it from my next bolus.

this much i know. sometimes, in order to keep my pump in the know, if i take a correction with a syringe, i detach my pump from my site, and i bolus whatever i am using with the syringe, so that this way, the pump has some idea of how much active IOB i have going at any given time. (this is something i rarely do; basically only when i need to correct a very high BG, like 300 )

The short answer I think, for your situation, test and bolus for the TUMS. At dinner, test and bolus for the dinner.

also, my Wizard keeps my target range BG in mind; it will automatically make a correction suggestion when neeed. for instance, if my BG is 75, but my target is 120, the Wizard will suggest a smaller dose of insulin to bolus for, also, at the same time, keeping in mind whatever IOB is still active.

am i making sense?


and, as far as deciding to eat a desert after a meal, i would just make an educated guess about how many units to bolus for. yes?

That is what I always do.

Either that, or find out how many carbs are in that specific dessert using Calorie King or one of the other apps. Bolus for however many carbs it is.

Yes, actually that is the smarter answer. I wasn’t stating it very well, I simply meant to ignore the “insulin stacking - don’t take insulin for dessert” warning!

Yeah. The short answer is to dose the desert carbs.

After that it is fine tuning. Advising somebody NOT to dose for desert is crazy talk.

thanks. thats what i have done in the past. particularly when at a restaurant. i just kind of “ball-park” it. ( like if i want a piece of pie, for example. ). i just wasnt certain. i was thinking," ugh, my tummy really hurts, but if i take the TUMS now and bolus for it, wont that mess up my dinner bolus, which is only about an hour away…or should i put off dinner till later, even though i know i will be hungry earlier." make sense???

I am trying this tonight. I had to take a correction after 2.5 hours after dinner, and then want my lg cup of warm milk before bedtime. So I will just manually bolus for the milk and not use my pump’s Wizard function. So if I wake up at 2am at 35 bg, I will have learned a new lesson :wink:EAT chocolate :grinning: