When a person is starving, glycogenolysis is initiated first, and the amount of glycogen in the reserve varies among individuals, so the time to start fat consumption is not exactly the same, and most people can start to consume fat on the first day after they stop eating. When the body is in a state of hunger, because it cannot take in enough nutrients from the intestines to maintain the body’s needs, that is, to use the body’s reserve energy to maintain the normal activities of the body, which includes the consumption of fat to provide energy. Normally, starvation first consumes sugar in the blood to meet the body’s energy supply, then begins to break down liver glycogen and muscle glycogen to produce glucose for the body to consume, and only begins to consume fat if it continues without food. If you fast for a long time, although it is good for weight loss for a short time, it poses a threat to human health. Therefore, it is not recommended to consume fat through starvation methods, the correct way to achieve the purpose of fat loss through exercise and proper control of diet.