A lot of people when it comes to the cause of obesity, the first thing that comes to mind is basically “eat more, exercise less”, although these two points are indeed the main cause of many obese people, but the cause of obesity is also much more than these two points. The reason of obesity is complicated and various, besides with the diet has the relationship, heredity, the baby’s birth way, the medicine, the body inside the hormone and so on will have the influence on the obesity. These are also issues that we need to be aware of when conducting weight loss education campaigns. For example, some people are born with a tendency to be fat. There are many data show that the parents or grandparents obese children will be more likely to become fat than the parents and grandmother’s weight are normal children, especially the mother’s weight obese or not more likely to affect the child’s obesity probability. There is another characteristic of obesity, simple obesity is generally caused by the increase in the number of fat cells or increase in the number of fat cells, and the number of fat cells will generally only increase during development, and after adulthood, their number is usually more stable. Therefore, it is more difficult for children and teenagers to lose weight than adults, and even if they succeed in losing weight, the probability of them becoming fat in adulthood will be greater than others. In addition to genetic problems, people are not only difficult to lose weight after becoming fat, the possibility of continued weight gain is also very high. In the body there is a hormone called leptin, the role of this hormone is to regulate appetite and metabolism. When a person’s body fat increases, it will increase the secretion of leptin, suppressing the appetite. But obese people are more prone to leptin resistance, even if leptin secretion increases, but also can not effectively suppress the appetite, so that people consume more food. In addition, intestinal bacteria is also one of the reasons for becoming fat. Intestinal bacteria are very important to human health and can play a role in promoting digestion. However, one study found that obese people may have different gut bacteria than normal people, and the gut bacteria in their bodies can make people get energy from food more efficiently, leading to obese people being able to store fat more quickly. There are many other factors that contribute to obesity, and it is the combination of these factors that makes it difficult to control weight after it has been gained. This is where the benefits of weight loss surgery come into play. It is not as simple as just controlling the diet as people think, but more importantly, it also improves the endocrine environment of the patient and brings back the hormones related to obesity to normal, which is something that traditional weight loss methods cannot do.