There is no reason to follow a fad diet. There is no reason to count calories. You can eat what you want and lose weight. It's not easy, but the science will set you free! This is a very short (1600 word) explanation of the science behind gaining and losing weight and how you can use that information to gain or lose weight and avoid costly fad diets. This is one appendix from the book: What Your Doctor Won't Tell You About Your Lower Back.