so....leptin is the hormone stored in fat so the fatter you are, the more you have. Leptin is the reason why we lose weight and our appetite increases...our body starts thinking we must be needing to eat more because we have fat and therefore less leptin.
I looked over this diet and it's nothing too special-the food recommendations are similar to a diabetic diet. I think it's a way to sell supplements/products, because the diet itself doesn't look too far from what I am doing now and unfortunately I am not losing weight at breakneck speed LOL
Take my opinion with a grain of salt because I am always skeptical of stuff like that.