A whispered to B, “This man is so fat, he must have fatty liver and diabetes.” B said in confusion, “Don’t thin people get diabetes?” A said with conviction: “Of course not! Skinny people can also get diabetes, everything is not so absolute”. Indeed, among the more than 100 million diabetics in the country, most of them are fat, but of course, there are also a small number of thin people, so thin people can also get diabetes. Generally speaking, thin people get diabetes because the pancreatic β-cell function is damaged resulting in insufficient insulin secretion, lack of insulin in the body, energy can not be stored, it is naturally difficult to gain weight. But most of the type II diabetes patients are obese at the beginning, the function of the islets is not completely lost, obesity will produce insulin resistance, when a person’s body insulin resistance is too high, the pancreas to secrete far more than the normal dose of insulin to control blood sugar, and the pancreas because of long-term in the overload work state and failure, then the obese people will slowly become thin. Diabetes surgery is not for everyone, but only for those who have good islet function. The better the function of the islets, the better the effect. After the surgery, the hormones in the body will change, which will reduce insulin resistance, and at the same time control the diet, reduce absorption directly lower blood sugar, when the islet function fails, then go to do diabetes surgery may not achieve a good effect. Here to see those who are suitable for diabetes surgery: “Chinese Guidelines for the Surgical Treatment of Obesity and Diabetes Mellitus (2014)” stipulates: I. The duration of type II diabetes mellitus ≤ 15 years, and the pancreatic islets still have some insulin secretion function, fasting serum C peptide ≥ the lower limit of normal value of ? Second, BMI (body mass index) ≥ 27.5 kg/㎡. Third, the recommended surgical grade can be increased at the discretion of men with waist circumference ≥ 90 cm and women with waist circumference ≥ 85 cm. Fourth, the recommended age for surgery is 16-65 years old. Gastric bypass surgery is the “gold standard” procedure for weight loss and diabetes. It reconstructs the digestive tract and creates a small gastric bursa in the upper part of the stomach to limit food intake and reduce food absorption. It is indicated in all cases of obesity and type II diabetes.