Modern medicine proves that after eating, insulin secretion increases as blood glucose rises in normal people, so that blood glucose drops and is maintained in the normal range, and therefore, diabetes does not occur. In the case of diabetic patients, insulin secretion is absolutely or relatively insufficient due to pancreatic islet function reduction, and insulin cannot increase with the rise of blood glucose after eating, so it cannot play an effective role in lowering blood glucose, so blood glucose will exceed the normal range. At this time, if you eat like a normal person, without diet control, or even over-eating, it will make the blood sugar rise too high, and will have a negative impact on the islet tissue that is already under-secreted, so that the function of the islet is more reduced, and the secretion of insulin is more reduced, thus further aggravating the condition. Therefore, it is important for diabetic patients to have reasonable dietary control. Diet therapy is the basis of treatment for all types of diabetes, and is one of the most important treatments for diabetes. Regardless of the type of diabetes, the severity of the disease or the presence of complications, whether treated with insulin or oral hypoglycemic drugs, should be strictly carried out and long-term adherence to dietary control. For obese type II diabetic patients or elderly light cases, diet therapy can be made the main treatment method, appropriately combined with oral hypoglycemic drugs, it can achieve the purpose of effective disease control. For type I diabetes and severe cases, it is more important to actively control diet on the basis of insulin and other drug therapy in order to effectively control blood sugar and prevent the deterioration of the disease. Therefore, diet therapy is the basic therapy for diabetes and must be strictly observed. The purpose of diet therapy is to (1) reduce the burden on the pancreas so that blood glucose and blood lipids can reach or approach normal values and prevent or delay the occurrence and development of cardiovascular and other complications. (2) Maintain health, so that adults can engage in various normal activities and children can grow and develop normally. (3) Maintain normal body weight. Reducing caloric intake in obese people can improve the sensitivity of receptors to insulin. Lean people can make weight gain to enhance resistance to infectious diseases.