Low Carb ketogenic diets, ones in which people are adapted to oxidizing fat for energy, can cause a temporary insulin resistance state - the Randle Effect.
If insulin resistance is one of the primary ways in which women develop PCOS (polycyctic ovarian syndrome), would a low carb, ketogenic, paleo diet in effect also cause a PCOS-like state? Is insulin resistance which is developed through metabolic derrangement/over consumption of fructose, etc. somehow different from the insulin resistance which is self-imposed through very low carb high fat diets?
It's not really the "insulin resistance" that's the problem, it's the hyperinsulinemia that's the problem, i.e., having tons of insulin floating around your body all the time. You can't take one "number" (insulin resistance) and assign it as "good" or "bad" without knowing the context. In a fat-burning healthy person, insulin resistance is not bad, and is probably beneficial. In a metabolically deranged sugar-burner, insulin resistance is bad. But it's not the insulin resistance, per se, that's bad, it's the resulting hyperinsulinemia that causes the problems. So when people say you need to work on becoming more insulin sensitive, that's for the metabolically deranged. Once you're a fat-burner, measuring your insulin sensitivity is probably not a meaningful quantity anymore.
Yes, the insulin resistance seen on a low carb diet is dramatically different from that in a disease state. In fact, a ketogenic diet is helpful to diseases characterized by insulin resistance, including diabetes and PCOS.