MDI bolusing and extended bolus for complex food

I am looking for help and advice on how to best bolus and extend bolus for complex food using MDI.

First, I wish to have help in clarifying “complex food”. Please help me understand why pasta with some chicken thigh meat seem to cause my BG to rise at around 3 hours time. The meal is about 25 g of olive oil and garlic pasta (Barilla, or San Giorgio), chicken thigh, smaller than the size of my fist and some steamed green leafy vegetables (broccoli, Chinese broccoli, spinach, or some other green leafy vegetables).

5;15 pm BG 147
took 1 unit correction - estimated to decrease BG by about 50; points. snacked on half slice of liverwurst, and a few walnuts.
5:45 pm BG 129
3.5 units
6 pm dinner - pasta, chicken thighs, green vegetables.
6:30 pm 2.5 units
8 pm BG 123
9 :15 pm BG 194
took 1 unit correction
10:15 pm BG 175
took 0.5 unit correction
midnight BG 139

For quite some time, I did not eat “white stuff” (bread, pasta, rice) as part of a meal, therefore, I have not learned to bolus. As @Eric mentioned, diabetes shouldn’t limit us. I don’t want my inability to bolus for foods to prevent me from enjoying food.

Using MDI, how do I space my injections? I’ve read about pumpers who extend their bolus over 2 1/2 hours (or whatever time works for them) For pumpers, does this mean that there is a steady trickle of x amount of insulin for the next 2 1/2 hours? How would I accomplish that using MDI? Would I inject for example 0.5 units every 30 minutes or so for 2 1/2 hours?

Are meals consisting of starch and protein and leafy green vegetables complex? Salmon would be oily, chicken thighs, pork would be oily. Unless someone ate only a plain potato, wouldn’t most meals be complex? I try to keep my carb portion to about 30 g. I am guilty of being an imprecise, and carb counter; more like an estimator. I look at the meal and try to eat similar meals.


Do you think that this response might be uncorrelated to the meal?

With my son, since he has got into his hormonal teens, we have seen many peaks uncorrelated to food.

[I will reply a bit later to your questions with my very tentative answers as I am cooking dinner:-)]

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Yes. With a pump, you can specify what amount to give immediately at the beginning, and for the extended part, what amount to give and over how much time.

You could, but that sounds like too much work. You may be able to get a reasonable result with one bolus at the beginning of the meal and one later on, like maybe 2-1/2 hours later since you saw the BG rise come on at 3 hours.

“Complex” is just a hint about what to expect. If I eat 10 grapes I’d expect my BG to spike. If I eat the same amount of total carbs in a meal that has significant fat and protein, that would slow the digestion so I’d get a smaller spike and maybe a rise later because the fat and protein are slower to digest into glucose. So focus on what happens to your BG. If a certain kind of food gives you a late rise, use the split bolus where you take insulin up front and more at a later point.

Yes. What matters is how large the amount of carbs is compared with the amount of fat and protein. If the carb amount is relatively large, a single bolus up front is more likely to work out ok. If the carb amount is small compared with the total nutrient value of the meal (which I expect is true for most meals that have 30g carb or less) then it’s likely the the digestion will be slow, and just bolusing for the carbs up front will work at first but there will be a late BG rise as the other nutrients kick in.

That’s fine, it just means you’re more likely to need small adjustments to push the BG back in a good direction if it starts wandering off too high or too low. There’s nothing wrong with coarse estimates instead of careful weighing, it just requires measuring the BG a few times during the digestion and taking the insulin or carb corrections when needed.


I am also guilty of not measuring the fat, protein. this meal was: The pasta is about a handful, the chicken is about a handful. The green leafy vegetables, more than a handful. I know that this sounds so imprecise!

Suppose, if the meal were only or mostly pasta- olive oil and garlic (80g+ carbs), with no chicken or 2 small strips of chicken- would the BG rise be likely earlier rather than later( + hours)? I would not eat a pasta only meal- I like my meat :-). I really want to learn about the food and the impact on BG. (On a different occasion, I corrected a low with a small amount of yogurt- BG rose 2 hours after the yogurt correction. I was hoping that it wouldn’t rise after 2 hours. It rose for another 2 hours! I wanted to like and enjoy my ‘correction’- not just a Dextab. Diabetes management isn’t just about counting carbs. Sigh…

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100% agree!

Here are some thoughts based on what we do and what works for us:

  • Weighing vs eyeballing: we typically weight a meal to match the bolus, say about 75% of the time. But 25% of the time my son eyeballs it the same way as you do, and he is right about 80% of the time he eyeballs. But there are times when he is way off.

  • we largely discount green veggies: when my son is in a very high peak (very often with teenage hormones), we make him a very low carb meal, such as green veggies and proteins (typically chicken), with, for desert, a very low carb fruit such as raspberries. These meals are largely invisible to us on his CGM.

  • Bolus timing: I noticed that you ate 15 minutes after you injected. My advice would be to study your insulin activation timing. For us, Novolog activates in 45 minutes, while FIASP activates in 25-30 minutes. So, if my son is in range, we will prebolus by that long, and eat when he “turns the corner.” If he is a bit high, we add a correction to the bolus, and prebolus earlier. This way, we always eat while he is in range. When we do a good job, he rarely goes out of range after eating. His CGM sometimes shows him going really low before coming back up, but, in reality, a manual test shows him to be in range.

  • Injection spacing: for a light carb meal like yours, we do not need multiple injections (or an extended bolus). For, say, 35 carbs, we would inject 3 units pre-bolused, then eat. When we do need to do an extended bolus (heavy carb meals with large quantities of fat, for us), we can replace an extended bolus by injections spaced every 60 to 75 minutes. We find that spacing 90 minutes between injections does not work as well. So, for us, when we are on pump vacation (hardly ever), we would pre-bolus as usual, then wait 1 hour or 1 hour 15 minutes after the prebolus and inject to replace an extended bolus, then, if needed, do it again 1 hour or 1 hour and 15 minutes later.

  • Your late peak: I cannot explain your late peak by our lights, unless there was a huge amount of oil in the prepping. Large amounts of fat (or enormous amounts of protein) are the only things we have found to cause late food peaks for us. By our lights, the amount of carbs you ate was low. We typically have 40-50 carbs in a meal, and sometimes much more when we have to refuel from a swim or a long run (up to 100 carbs in a meal in that case, although it is more often 80 carbs).

  • Complex meals: for us, a small amount of starch + protein + leafy vegetables is not a complex meal. What would be a complex meal would be, for instance, large starch + protein + large fat.

From what I have seen here, it appears that we all vary very widely as to how we can deal with food. I know, for us, it can take many tries to get a complex meal dosed well…


Excellent! The way to do that is to try something and watch what happens, and if you’re not satisfied with the result, then do it a little different next time and keep trying things to find out what works. Stories here can give some hints for what to try, but every body is different.

Someone has a saying “Never waste a good low” which means if you need a carb correction (and it’s not an emergency) then by all means eat something tasty. But not too much of it; that’s the hard part. So in your particular case, one possibility is that the amount of yogurt you ate had more carbs than needed. You could try half the amount next time to see what happens. A second possibility is that your basal rate is a little too low, so your BG rose 2 hours later because it was going to go up anyway because you needed more basal. Some folks will do careful basal testing: no eating or exercise and measure frequently to see if the BG is going up or falling down all by itself. I’m less formal about it. I just pay attention looking for when my BG seems to be rising all by itself around the same time every day. That means I needed more basal. Or if I’m drifting low around the same time every day that means I need less basal. After 8 years of MDI I started pumping because it turns out that I need about 6 times as much basal overnight as I need in the middle of the day, and a pump can do that.

I absolutely agree with that. For me, it’s about paying attention to where my BG is going, so if it starts to wander off I can make a small correction to push it in a good direction. Carb counting just helps me get a better meal bolus to help keep the BG from storming off madly out of range. In either case I expect to have to adjust it, but small adjustments are more calm.