Diabetes mellitus is an ancient disease that was first recorded in the Emperor’s Classic of Internal Medicine as a disease of thirst. According to modern medicine, diabetes is a lifelong disease with a very complex etiology and is a chronic systemic metabolic disease whose basic physiological characteristic is an increase in blood sugar level. The basic physiological characteristic is the increase of blood glucose level. When the blood glucose increases, there can be three more and one less, that is to say, eating more, drinking more, urinating more and losing weight. Long-term elevated blood sugar will lead to multi-organ tissue damage and a series of complications, such as cardiovascular, cerebrovascular, renal, retinal and neurological lesions, etc. In serious cases, acute ketoacidosis, hyperosmolar coma and lactic acidosis may occur, which may even threaten life. Now we are all talking about “sugar”, but diabetes can be prevented. Specific measures include the following: (1) Prevent and correct obesity. (2) Avoid a high-fat diet. (3) Diet to ensure a reasonable weight and the needs of work and life. Food composition is reasonable, carbohydrates are good for non-refined and rich in soluble vitamins, accounting for 50% to 65% of total food calories, fat accounts for 15% to 20% of total food calories (the ratio of polyunsaturated fatty acids to saturated fatty acids is greater than 1.5), and protein accounts for 10% to 15% of total food calories. Eat more vegetables. (4) Increase physical activity and participate in physical exercise. (5) Avoid or reduce the use of drugs that are detrimental to glucose metabolism. (6) Actively detect and treat hypertension, hyperlipidemia and coronary heart disease. (7) Quit bad habits such as smoking and alcohol. (8) Conduct regular health check-ups for middle-aged and elderly people. In addition to regular fasting blood glucose, attention should be paid to the measurement of blood glucose 2 hours after meals. (9) insist on breathing air negative ions, negative ions on the treatment of diabetes has a long-lasting and smooth characteristics, while easy to adhere to, is the latest spectrum of efficient diabetes treatment methods. There are also many foods that are beneficial to diabetes treatment everywhere in daily life, such as: cowpea jelly, green tea, eel, asparagus, nori, mussels, okra and so on. At present, many scientific studies also prove that selenium is beneficial to the treatment of diabetes, therefore, diabetic patients can eat more selenium-rich foods in their daily supplementation, such as fish, mushrooms, sesame, garlic, mustard, etc.