Diet therapy is one of the basic treatments for diabetes. Even if a patient has been treated with insulin or oral hypoglycemic drugs, diet therapy should not be relaxed in any way. The dietary treatment plan for diabetes is based on the principles of medicine and nutrition. It is necessary to ensure physiological needs while keeping blood glucose stable in order to serve the purpose of correcting metabolic disorders in patients and delaying the occurrence of macrovascular and microvascular complications of diabetes. The dietary treatment of diabetes has gone through several major developmental stages: It started with complete starvation therapy, where the patient’s staple food intake was very low, only 1/3-1/5 of the current staple food intake of diabetic patients, which eventually resulted in adverse consequences such as hypoglycemia and low body weight of patients. The second stage was the staple food control stage, i.e., with a higher proportion of fat and protein and a smaller proportion of staple food, which was also found to be bad after decades of experience. Since then, with the development and advancement of evidence-based medicine, endocrinologists and dietitians gradually realized that it is still advisable to focus on sugars (carbohydrates), with protein and fat as supplements. Among them, carbohydrates should account for 60-65% of the total daily calories. This approach is now accepted and used by everyone. Carbohydrates, proteins and fats are the three major nutrients needed by the body. Diabetic patients should consume the following 8 types of food daily: cereals, vegetables, fruits, soybeans, dairy products, meat, eggs and fish, nuts and fats. Among them, cereals, vegetables and fruits belong to carbohydrates, soybeans, dairy products and meat, eggs and fish belong to proteins, and hard fruits and fats belong to fats. The reasonable proportion of daily intake of the three major nutrients for diabetic patients is 60-65% for carbohydrates, 15-20% for proteins and 25-30% for fats. According to the patient’s height, weight and work intensity, we can calculate the total daily calorie intake of the patient, calculate the calories of each of the three major nutrients according to their respective ratios, calculate the grams of carbohydrates, proteins and fats needed according to the formula, and then distribute them according to the three meals per day, which is usually called the number of main meals and the number of side dishes. Diabetic patients with stable blood sugar can eat fruits appropriately, pay attention to eating low-sugar type fruits, such as kiwi, dragon fruit, grapefruit, etc., and only in the middle of two meals, not after meals, so as not to cause post-meal blood sugar fluctuations.