We all know insulin is a hormone and escorts sugar into cells to be burned for energy.
However, not everyone knows that insulin has multiple functions. Some that can make you fat or make it easier to gain/retain weight. Some of it's other functions:
1) Signals for carb cravings.
2) Signals for fat to be retained and not be burned for energy.
3) Forces fat cells to convert blood lipids to triglycerides.
4) Speeds up aging.
5) Etc., etc., etc....insulin has MANY functions and most of them are not fully understood.
The more insulin there is...the worse these things can be. If you have insulin resistance you often have excess insulin in your system but your body can't use it to get glucose into cells...but it might be able to still be used for the above functions. This insulin can be from your own body producing it or insulin you inject.
If your body still produces insulin, your insulin levels increase when there is glucose in the blood from carbohydrates, when protein is ingested, or there is circulating adrenaline (stress, exercise, etc.).
Muscle cells and fat cells are effected by insulin's levels...and they make up about 2/3 of all our cells. So insulin has a BIG effect on our health.
Blood sugar control is a sign of how much sugar we have in our bloodstream. However, diabetes is much more complex than that. I personally have been around people who regularly inject excess amounts of insulin while eating tons of carbs and sugar. Yes, they may have a 4.5 HbA1c...but that insulin is making them gain or retain weight and who knows what else. So it's better to try to watch your diet and try to limit how much insulin you need from meds.
When I was diagnosed, I was told by the nurse, "Oh mija (little girl), I'm so sorry. I would rather have cancer than diabetes."
However, as diseases go...I think diabetes is pretty nifty in that you do have some control over it. I know the above stuff may make you feel like - omg, what the hell am I supposed to do then? But if you exercise, even just a little each day, it makes your cells produce more receptors so that you can use more of the insulin that's in your system.
Insulin degrades once it has been docked onto a cell receptor. So the more receptors you make, the more insulin you degrade or burn up.