I agree with Dngu047. I think that people worry so much about insulin. Calories count more than anything, to me. If calories are below maintenance, I don't think that you could possibly put on fat--look at the rice eaters on Survivor. I think controlling insulin helps control hunger, though. But this is just my theory. I really would like someone who has tried diets of the same total calorie, one low-glycemic or low carb, and the other high carb/high glycemic, to tell me the results of each.
Oh, and in terms of glycemic index, sugar isn't nearly as bad as potatoes. So does that mean we should eat candy instead of baked potatoes?