Bariatric surgery is a partial removal of the distal end of the stomach and anastomosis with the intestine. The principle is to remove part of the stomach, so that obese people can eat less and thus lose weight. So what are the causes of obesity? Is it good to do weight reduction surgery for obesity? Obesity: the external causes are mainly excessive diet and too little activity. Calorie intake more than calorie consumption, so that fat synthesis increase is the material basis of obesity. Internal because of fat metabolism disorder and cause obesity. 1, genetic factors human simple obesity onset has a certain genetic background. Some studies think, one of the two parents is obese, its children obesity rate is about 50%; Both parents are obese, its children obesity rate rises to 80%. Human obesity is generally considered to be polygenic inheritance, genetics plays a susceptible role in its development. The formation of obesity also with the way of life behavior, food intake behavior, hobbies, climate and the interaction of psychosocial factors. 2, endocrine factors Many hormones such as thyroxine, insulin, glucocorticoids, etc. can regulate feeding, so it is presumed that these hormones may be involved in the pathogenesis of simple obesity. Obese people to insulin resistance and lead to hyperinsulinemia, and hyperinsulinemia can make insulin receptor down regulation and increase insulin resistance, thus forming a vicious circle. Increased insulin secretion can stimulate increased food intake and at the same time inhibit lipolysis, thus causing fat accumulation in the body. Sex hormones may play a role in the pathogenesis of simple obesity. Is it good to have bariatric surgery for obesity? Laparoscopic gastric sleeve resection” is a weight loss surgery, which is called laparoscopic gastric reduction surgery. The principle of gastric reduction surgery is to use laparoscopy to cut out the large curve of the stomach vertically, and is mainly used for weight loss and treatment of type 2 diabetes. This surgery can reduce more than 70% of overweight weight in the first year after surgery, (about 60 pounds or more for 200 pounds, for example), and the remission rate of diabetes is more than 75%. Of the three, adjustable gastric banding for weight loss (LAGB) and diversion, it is the most popular because it has the middle of the pack in terms of treatment effectiveness and postoperative complications. Studies have shown that patients who underwent bariatric surgery were able to achieve complete remission of blood glucose in patients with type 2 diabetes compared to those who underwent only conventional medication.