Hi Derek,
Hope to find you in good health.
I don't think that insulin sensitivity is the correct way to describe the action of how sensitive we are to carbs, glucose or insulin itself.
I think that our second insulin response can be dependent on what our triggers response is to how much glucose is in our blood at the time of the pancreas produces the response. It is, if it turns itself off, I believe that mine has not got a way to stop production, until the liver decides to kick in whilst being hypoglycaemic, during Glucogenesis, my production still exists but is not enough to stave off the glucagon/glucose/glycagon response of my liver, so the blood glucose levels rise and of course we get into the phase of hyper, hypo, hyper, hypo, fluctuating bloods. The rebound effect we try to avoid.
We have to recognise that our first insulin response is weak, hence the second supplements the first, and doesn't behave itself.
Insulin resistance is a long term effect of having too much circulating insulin in your blood, this effect can cause the high blood glucose levels we can get if we don't get control, it also is the reason why it is necessary to fast for as long as possible before an eOGTT, so before diagnosis your blood levels can be as low if not in normal levels as possible. That was why my second eOGTT was repeated because my glucose levels were too high even though I had fasted. Diagnosis is dependent on having normal levels pre test.
I know of no other strategy or treatment, except that I use sitagliptin as an insurance against spikes, despite being in ketosis.
Best wishes mate.