You don't give human metabolism enough credit, as though you don't think that our bodies respond to different amounts of energy intake/usage. The main problem w

You don't give human metabolism enough credit, as though you don't think that our bodies respond to different amounts of energy intake/usage. The main problem with the calories in = calories out myth is that they are assumed to be independent variables when they are self-evidently not. When you work out more, your body demands more energy by stimulating appetite. When you eat less than your body needs, you get cold and hungry. The other problem is that it overlooks the role of insulin in weight gain. Insulin is the primary regulator of fat storage, this has been known for 50 years or more. Eating foods that stimulate insulin secretion are going to cause you to put on pounds - that's the job of insulin! If every type of calorie we consume contributes the exact same effect on the body, why do marathoners (or any other athelete for that matter) carb-load before challenges? Why not fat-load because everyone knows that fat has twice as many calories per gram? My main point is that not all types of calories cause the same types of effects. Cutting calories below expenditures does not lead to long term weight loss, it leads to hunger.