In some people’s view, although obesity can have a bad impact on their physique and health, they can lose weight through dieting, exercise and other traditional methods as long as they want to. But really wait until they go to lose weight, they will find that the difficulty of losing weight is far more difficult than they thought. The human body has a memory. A person of normal weight, as long as the habits and eating habits are good, generally are not easy to gain weight, even if they become fat until after middle age, in the basic metabolic rate decreases at the same time they do not adhere to the exercise, excess nutrition and lead to. Similarly, once people become fat, not only is it difficult to lose weight, the probability of re-fat after successful weight loss will also be greater. Obese people should have stricter requirements for their own diet and exercise, not only can not overeat, but also to adhere to long-term exercise, according to their own situation to control the daily energy intake, so as to successfully lose weight and prevent re-fat. However, in reality, not many people can do this, and most people can adhere to a certain amount of exercise, but it is difficult to control their appetite, which is the result of a combination of physiological and physical reasons and social environment. Physiologically, long-term obese people’s stomach to be bigger, need to eat more food to produce a sense of satiety; psychologically, the temptation of food is most people are difficult to resist, and at the same time, because people need to socialize, with friends together more likely to make themselves lose control and eat more.