The diabetic condition affects the patient’s body weight, and various types of drugs can have different effects on body weight in treatment due to their different pharmacological effects. Metformin can reduce body weight Metformin can increase the uptake and utilization of glucose by peripheral tissues (such as muscle), improve glucose metabolism and reduce body weight, but does not affect serum insulin levels and does not cause hypoglycemia when applied alone. Therefore, for obese type 2 diabetic patients, metformin belongs to the drug of choice. After this drug is taken, weight loss is a normal reaction, so patients need not worry. Insulin, sulfonylureas, glinides and glitazones gain weight Insulin not only promotes the entry of glucose into cells to supply energy to cells or store energy in the form of glycogen, but also promotes fat storage and prevents fat decomposition. Therefore, weight gain is a potential problem in insulin therapy. After treatment with insulin, the patient’s hyperglycemia is effectively controlled and glucose is not lost from urine for nothing, which, together with the patient’s high appetite, may lead to weight gain. Therefore, while using insulin, the total caloric intake of the day needs to be limited and exercise needs to be increased appropriately. Sulfonylureas and glinides belong to the same class of insulin stimulants. The basic principle of action of these two classes of drugs is to promote insulin secretion by pancreatic B cells, and their hypoglycemic effect depends on the considerable number (more than 30%) of functioning pancreatic B cells that still exist. In contrast, glitazones are insulin sensitizers, which can protect the islet B cells and increase insulin secretion. th cells and increase insulin sensitivity. Both classes of drugs either increase insulin secretion or insulin sensitivity, with the result that both enhance the body’s ability to store energy and allow weight gain. Glycosidase inhibitors, which do not affect body weight There is another class of drugs called alpha-glucosidase inhibitors, whose main principle is to inhibit alpha-glucosidase on the surface of small intestinal epithelial cells, slowing down the absorption of carbohydrates and lowering postprandial blood sugar, and they are effective only when there is a sufficient amount of carbohydrates (≥40%) in the diet. These drugs are especially suitable for patients with normal fasting blood glucose but significantly elevated postprandial blood glucose, and can be used alone or in combination with sulfonylureas and biguanides. α-glucosidase inhibitors do not cause weight changes, and therefore are not “picky” about the fatness of patients.