A big problem here is that there's the hyper response of insulin secretion, and then the hyper response to insulin. In the A to Z study, carbohydrate restriction seemed to be more effective for people who were insulin resistant. So is carbohydrate restriction not the way to go if you're insulin sensitive? I don't know if that's true, for somebody whose fat tissue is very insulin sensitive, the absolute level of insulin needed to promote fat loss might be considerably lower. So things get muddy, insulin has an undeniable effect in individuals, it's just that the required dose for a given effect has massive variability from individual to individual.

My own experience--I diet down to 155, 35 pounds lower than my top recorded weight. I've never had insulin resistance measured, but unless I do a serious carbohydrate binge, I've never caught myself with very high glucose numbers after a meal. Between this and much lower blood pressure than I had at 190 on a high carb diet, I'm probably more insulin sensitive--but foods that I wouldn't binge on at 190 pounds, that eating to appetite caused the opposite, spontaneous weight loss from that weight, became binge foods at the lower body weight. At that point, compliance to a more liberal Atkins approach became difficult--but pushing things further, more ketogenic, made compliance easier. In that A to Z study, higher compliance to Atkins among people who were insulin resistant was a major factor.