There's increasing public discussion about the health risks of chronic insulin resistance* (IR). In many cases there's a focus on high glycemic index foods that "spike" your blood sugar, which implies that a rapid increase in blood glucose is by itself sufficient to contribute to IR.
On the other hand, I've heard the claim that if a person is 1) moderately active, 2) not in caloric surplus, and 3) not already insulin resistant, then they will will quickly clear excess blood glucose by replenishing glycogen or through general energy expenditure. This is claimed to have no effect on IR, even though the individual was temporarily exposed to elevated glucose / insulin.
This leads me to two questions:
1) Is it true that high blood glucose is normalized substantially more rapidly in people who have depleted their glycogen, or who have higher energy needs?
2) Does repeated exposure to high levels of blood glucose contribute to IR by itself, or are high and prolonged levels of blood glucose required?
This has public health implications -- If the "spikes" theory is inaccurate, then glycemic index may not be very important to sufficiently active people**, and low glycemic index meals may not be as helpful as expected for people at risk of developing IR if total glucose exposure is high.
*"chronic insulin resistance" would exclude gestational diabetes and the reversible insulin resistance seen on ketogenic diets.
**For this discussion, let's ignore effects of blood sugar swings on hunger, mood, behavior, etc, since my interest is in the specific physiological triggers for IR.