Successful body weight reduction is not just a matter of losing pounds. The emphasis needs to be on abandoning body fat and avoiding reduction of lean body mass, primarily muscle mass. What is this the key to long-term success? Because muscle requires 15 times the energy compared to fat to survive which is 7.5 Calories per day for muscle versus 0.5 calories per day for fat. The more lean tissue, the more calories one can eat once desirable body weight is achieved. Overall, a moderate nutritional diet of at least 1000 calories of high quality food per day and physical exercise is clearly the best approach because 80% of the body weight lost is fat. This plan protects lean body mass, which is critical to keep from gaining the body weight back again.