This communication stuff isn't easy, but I think you are wondering about the time? If your carbs are in the bloodstream in 1.5 to 2 hours and the insulin takes 4 hours to act, how does that work?I still would like to know about "insulin on board". If you are taking rapid acting insulin and you have covered your carbs precisely, how can you still have insulin that is active for up to 4 hours? I don't understand this. :noidea:
The carbs are faster and that is really good. If you have a meal with only carbs, you get a surge of them quickly. The insulin works a little more slowly at taking down the hill (on the bell curve). That's how the time thing works.
Protein take about 4 hours to digest, so it is good that the insulins last this long.
With a carb meal it takes awhile for the insulin to catch up, and your glucose is above normal for the first part of that 4 hours.
Dr Richard K Bernstein "The Diabetes Solution" recommends eating mainly protein for this reason, and using R instead or rapid acting insulins. You would have to read the book for the details.
It's the only book on diabetes that I ever recommend. I don't follow it completely, but it is important to understand the way he uses insulin. Using his basic techniques, I have never had a 3 month average above the normal range.
That's as the normal docs define it. He gives a much more narrow normal range, and I haven't managed to stay in that for my 3 month averages.