The morning fasting blood glucose of the general population is 3.9-6.1 mmol/L. If fasting blood glucose <3.9 mmol/L, it is hypoglycemia; fasting blood glucose between 6.1-7.0 mmol/L is impaired fasting blood glucose and does not meet the criteria of diabetes; fasting blood glucose ≥7.0 mmol/L, coupled with the patient's recent unexplained weight loss, can be diagnosed as diabetes; fasting blood glucose ≥ 7.0 mmol/L and 2-hour postprandial blood glucose ≥ 11.1 mmol/L can also be diagnosed as diabetes mellitus. In case of pregnant women, the normal value of fasting blood sugar is 3.1-5.1mmol/L. If fasting blood sugar >5.1mmol/L, gestational diabetes can be diagnosed. If fasting blood glucose is >6.1mmol/L, whether the patient has impaired fasting blood glucose or diabetes mellitus, the diet should be adjusted according to the diabetic diet principles. Overall control of the calories eaten daily, less food with high calories, high fat, high protein and high oil, and no more than 250g of staple food per day. at the same time, carry out appropriate exercise to increase the sensitivity of peripheral tissues to insulin to achieve the effect of lowering blood sugar. Pay attention to weight control, because within the standard weight range, it can increase the sensitivity of insulin and reduce the occurrence of diabetes. If fasting blood sugar is <3.9mmol/L, along with symptoms such as panic and cold sweat, you should immediately eat food containing sugar to relieve the symptoms of hypoglycemia. If the blood sugar is too low and hypoglycemic coma occurs, the patient should be sent to hospital immediately and treated with intravenous infusion of glucose solution according to medical advice.