Glucose tolerance test generally refers to glucose tolerance test, which is also known as glucose tolerance test, and is usually best performed early in the morning on an empty stomach from 7 to 9 o’clock. Usually the glucose tolerance test requires fasting for at least 8 hours, that is, no more food after dinner the night before, no more water after bedtime, normal sleep, and fasting from 7 to 9 o’clock in the early morning of the next day for the test, thus avoiding the effect of diet as well as early morning activities on blood glucose. Prior to the glucose tolerance test, a normal diet with at least 150 grams of carbohydrates per day is required for the first three days. Before the test, stop using various medications that may affect the glucose tolerance test, such as diuretics and birth control pills. Do not do strenuous activities during the test and avoid drinking tea and coffee and smoking after starting the test. Glucose tolerance test should be conducted under the supervision of a physician.