Something to keep in mind is that insulin is not the only player here. Protein also has a significant effect on glucagon and Gh. In study after study isocaloric diets with varrying amounts of PCF showed the most fat loss or least fat gain on the lower carbohydrate diets. Once again however this is not the whole story from a Paloe/e-fitness perspective as one does not endeavor to be skinny, but to carry appreciable amounts of (preferably) fast twitch muscle. As someone mentioned previously, insulin is highly anabolic and one is hard pressed to gain muscle on a low carb diet. Enter macronutrient cycling in chich one carbs at specific times to enhance both fat burning and muscle gain. I suspect that Professor Devany will recomend the macronutrient cycling in a highly randomized way. Rob Faigan in Natural Hormonal Enhancement recomends a highly structured plan as does John Bernardi at testosterone.net(racy site, not for the faint of heart!). Another thing to keep in mind is that latitude greatly influences the availability, both amount and frequency, of fruit and carbohydrate containing vegetables. Interestingly as on goes farther north one on average receives less light, and consumes more fat and protein. This seems to have effects on dopamine/serotonin levels. None of this is simple straight forward stuff. Something which seems obvious is overconsumption (perhaps frequency?) of carbohydrates increases the likelyhood of syndromeX. Treatment of syndrome X involves a reduction of carbohydrates and hopefully increased physical activity. Even though protein carbs may create a similar hyperinsulinemic state, the two nutrients are utilized very differently...moment to moment...day to day.