The most common types of bariatric surgery are sleeve gastric and gastric bypass surgery, and the range of procedures that derive from them. After sleeve gastric surgery, only the less curved side of the stomach remains, while the majority of the stomach remains in the abdomen after gastric bypass surgery, no longer connected to the esophagus. So if something goes wrong with this large portion of the stomach it is very difficult to detect in the early stages. So who can’t have gastric bypass surgery for weight loss surgery? Probably because of ethnicity, stomach cancer ranks third in the incidence of malignant tumors in China, while the highest incidence of malignant tumors in whites is prostate cancer and breast cancer, except for lung cancer, and the incidence of stomach cancer is extremely low. A survey found that the incidence of gastric cancer among Japanese Americans three generations later is also much lower than that of Japanese. Gastric bypass surgery was also invented by Americans, and although the distal part of the stomach cannot be observed after gastric bypass surgery, they do not have to worry about the occurrence of gastric cancer. Chinese, however, cannot ignore gastric cancer. If a patient has chronic atrophic gastritis, positive HP(+) for H. pylori disease, intestinal epithelial hyperplasia, gastric ulcer, and moderate to severe atypical hyperplasia in gastritis, and other lesions. Obese or diabetic patients with these diseases are generally not recommended to be gastric bypass patients because gastric cancer is the third most common malignancy in China, and the distal stomach cannot be observed by gastroscopy after gastric bypass surgery. It leaves a great hidden danger for patients. Sleeve gastrectomy, instead of increasing the risk of gastric cancer, decreases the risk because it can simultaneously remove the lesion areas such as mesenchymal tumor, gastric ulcer, intestinal epithelial hyperplasia, and atrophic gastritis on the side of the greater curvature of the stomach, in addition to implementing traditional gastroscopy for early detection of neoplastic gastric lesions. At present, the sleeve gastric and the small intestine open-ended and small intestine diversion procedures added to the sleeve gastric have gradually become the mainstream of weight reduction, and they have shown good efficacy not only in weight reduction but also in the treatment of type 2 diabetes.