hi @TiJoy Joy, welcomt to TypeOneNation…
I am a little confused, actually, as “healthy” and in-range blood sugars are not always perfectly aligned. When your body completely stops making insulin, blood sugar in the normal range of 70mg/dl to 100 mg/dl, all the time, is just not practical. There are inaccuracies in blood glucose readings, food carb labeling, and varying levels of activity that happen continuously… If I have any kind of life, and would like to be able to, for example, to just take a walk with my wife and son after dinner, it can have a huge affect on blood sugar that I would have to compensate for - in this example and if it was after I just took my meal insulin, that I would have to “load up” on carbs to go on that walk and “trial and error” for the next 2-3 hours afterwards. you know, I’ll never remember an “out-of-range” blood sugar but I’ll never forget the times with my family.
anyway I suggest a book called “Think Like a Pancreas” as it has a lot of information in it.regarding insulin-carbs-exercise.
okay so insulin is a moving target. Once upon a time it was made out of ground up pig and cow pancreases and mixed with chemicals to keep it from absorbing too fast, which was not a problem because it stank and even the fast insulin was slow… Today it is human (ish) rDNA based synthetic insulin, no longer animal based, and there are 2 typical formulations… the fast acting and the long acting. In my opinion, the best way to think about why it is this way is because of what your body needs: your body needs background insulin all day long. This background (called basal) insulin is not a very large amount, but you need it all day - for example, typical basal insulin rates are about a quarter to a whole unit of insulin per hour every hour. So this “lantus” (Insulin glargine) is formulated so that if you took 12 units, in the morning, that generally and most typically is the equivalent of 1/2 unit of insulin per hour for 24 hours because it absorbs over 24 hours. if you took 24 units… it is the same as a 1 unit per hour basal rate… etc.
you can, with a pump, do a pretty good job with fast acting only… and that is because the pump can give you a smidge every 10 minutes (to mimic your “basal” rate), and then as many units as you need all at once, for a meal.
fast insulin, such as humalog is because when you eat something, you want a large amount of insulin to act fast, to cover the carbohydrates you just ate. this is considered a “bolus” of insulin, but “meal time insulin” is just as correct. it take 15 minutes to several hours to absorb the carbs (averages) from a meal, depending on how much fat it is mixed with and how fast the carbohydrate is (glycemic index). all carbs are carbs, but the carbs in ice cream absorbs way slower then rice or processed table sugar
so humalog and the derivatives are considered fast, and are for both meals, and for when if you get a reading like 200 mg/dl and want to be 100 mg.dl you can inject fast acting to “correct” a error from a previous meal or whatever.
Diabetes is a disease where you get to be the doctor, you get to make these hourly decisions about food-activity-insulin, you get to take readings by drawing blood or by CGM, and you will learn and become and expert, generally, in about 10,000 hours (a year and 3 months)
good luck, I’ve been doing this for 40 years and I’m still alive, there is a lot of experience here. hope to see you around.