For example, diets with less than 800 calories a day, such as "fasting on weekends", "three-day apple diet", "quick tomato diet" and "a pack of ××× kg diet", are medically "extremely low calorie diets", which will lead to decreased thyroid hormone secretion, slow metabolism and long duration. You may faint because of too few calories. Worst of all, the percentage of fat lost is very low. When you resume dieting, your brain will give instructions to your body to store more fat in response to your "catastrophic fasting", which is called rebound.
The composition of muscle is very different from that of fat. If the muscle group is composed of muscle fibers, that is, protein, it will be gradually lost without continuous training or blessing. There are various forms of fat transformation, which are easy to accumulate but not easy to consume.