Weight loss is a topic that is often on people’s lips, whether male or female, fat or thin, can not help but mention it intentionally or unintentionally. However, there are many people who lose weight, but few succeed. There is a famous saying in the weight loss circle: the world’s most beautiful three words, not “I love you”, but “you’re thin”. It can be seen how difficult it is to lose weight, and it is estimated that finding an object is easier than this. Since people are aware of the dangers of obesity, a variety of weight loss methods have emerged. In addition to the most basic exercise, diet, medicine, there are many different methods, steaming, dumping, shaking …… In addition, China also has its own special weight loss method – the cave, acupuncture, qigong, massage. Of course, some of these are still somewhat scientifically based, but most of them are of little use and can withstand the test of only a few: diet control, physical exercise, behavior change, drug control (appetite suppression is the main focus) and surgery (such as gastric bypass surgery and sleeve gastrectomy). However, with the exception of surgery, which is a mandatory intervention, the rebound rate is generally high. There are many claims for the reasons for weight loss rebound, lack of willpower, improper exercise methods, old habits that are difficult to change, and eagerness to achieve, but these are said to be subjective factors, and an article published in the New England Journal by a team of Australian researchers said that weight loss failure may be related to the body’s secretion of leptin and growth hormone. (Sumithran et al. published in 2011) Leptin: Leptin works by suppressing a person’s appetite and has a relationship with fat content. They found that when the fat content becomes less, the leptin content decreases, which makes a person’s appetite increase, and also makes the body’s basal metabolic rate decrease, which leads to an increase in fat. When fat increases, the amount of leptin will increase accordingly. Growth hormone: The human body cannot develop without the role of growth hormone, which affects many of the body’s life activities. One of the roles of growth hormone is to stimulate hunger. Normally the growth hormone secretion in adults is reduced year by year, but when the body fat and weight loss, the growth hormone level is higher than before. When a person loses weight, both of these hormones play a role in making the appetite increase, so weight loss rebound, most likely caused by these two hormones. Weight loss is a long-term plan, which requires not only strong willpower to overcome various physical and psychological effects, but also a reasonable and effective method. The key is not to be discouraged, do not give up because of a few failed attempts to lose weight, after all, there are not only external factors that prevent you from losing weight, but also your body.