When losing weight, we need to know two concepts, what is weight loss and fat loss? Weight loss is the reduction of total weight, including muscle, fat, water, etc. And fat loss is a reduction in the amount of fat or a reduction in body fat percentage. The balance of our body composition is the most basic condition to maintain a healthy state, and the body composition is divided into two parts: body fat weight and defatted weight, also fat composition and non-fat composition. The non-fat component includes the weight of various components such as internal organs, bones, muscles, water, and mineral salts. Therefore, a truly healthy and effective weight loss should aim at fat loss, and through monitoring the changes in body muscle, water, fat and other indicators, the body will reach a balanced state internally by reducing body fat, so as to achieve only fat loss without losing other nutrients. And weighing may seem to be the easiest means to detect the effect of weight loss, but the body is not determined by weight, but by fat. A scale can only tell you the total weight of your body, but it can never tell you if your weight gain or loss is due to water, or changes in muscle or fat. The composition of a person’s body weight as a percentage is 55% water + 20% fat + 20% protein + 5% inorganic salts. A decrease in any one of these four components will cause weight loss. Therefore, although weight loss, but not necessarily a reduction in the proportion of body fat, it is likely that the loss of muscle and water; similarly, in the process of weight loss weight is not reduced or not significantly reduced does not equal to no reduction in the proportion of fat. Therefore, many people in the process of weight loss, on the water to reduce the water, it seems to reduce some weight, however, but not the fat to lose, so or weight loss failure. A good weight loss method should be one that reduces the amount of body fat and maintains or even increases the body muscle rate. Muscle is very important to the human body, the normal functioning of various organs in the body, including the heart, kidneys, limbs of the skeletal muscles and other functions need the participation of muscle, excessive loss of muscle may also damage these functional organs, accelerated aging, etc..