Gastric diversion surgery was actually first used in bariatric surgery, and it can be said that it is actually a bariatric surgery to come, but after several years of clinical practice, doctors accidentally found that this surgery can effectively treat diabetes, thus gastric diversion surgery, a new gospel for diabetic patients. A comprehensive analysis of 22,094 patients showed that 84% of type 2 diabetes was in complete remission after the procedure, and most patients stopped taking oral medication or insulin therapy before discharge. However, many people may wonder why this “gastric diversion” surgery can treat type 2 diabetes. The following is an introduction to the principle of “gastric diversion” for the treatment of type 2 diabetes. The causes of type 2 diabetes are: 1. K cells distributed in the stomach and intestines are stimulated by food to secrete insulin resistance factor, which makes the body insulin resistant; 2. Islet cells are damaged by the action of insulin resistance factor and apoptosis. Gastric diversion” is a surgical procedure to change the physiological flow of food through gastrointestinal anastomosis and entero-intestinal anastomosis, which has an effect on the function of islets: First, after the surgery, the food in the upper digestive tract is diverted and no longer passes through the distal part of the stomach, duodenum and the upper part of the jejunum. This part of the digestive tract has a large number of K cells distributed in the mucosa, and as soon as the food is stimulated, the K cells secrete a large number of cytokines, which are collectively called insulin resistance factors, causing the body to develop insulin resistance, which is the initial cause of diabetes. This is the initial cause of diabetes. If we do a diversion, the upper digestive tract no longer receives food stimulation, the secretion of these insulin resistance factors by K cells disappears, and the body’s insulin resistance phenomenon is weakened, thus removing the initial cause of diabetes. Secondly, the food that is not fully digested can enter the lower and middle digestive tract earlier and stimulate a large number of substance L cells inside the mucosa of the lower and middle digestive tract. after the food stimulation, L cells will secrete some cytokines such as PYY and GP1, and these cytokines have the following effects: first, directly lowering blood sugar; second, reducing the rate of islet cell apoptosis; third, stimulating islet cells to add value. In other words, the number of islet cells can be increased from one to two or two to four; these cytokines can also protect islet cells from glucotoxicity and some other inflammatory diseases. In this way the second major cause of diabetes is also removed. In summary, after gastric diversion surgery, both causes disappear and diabetes is effectively treated.