Glucose tolerance generally refers to the glucose tolerance test, and eating a small amount of sweets the day before the glucose tolerance test usually has no great effect. Glucose tolerance test is a glucose loading test, which can clarify the function of pancreatic β-cells and understand the body’s ability to regulate blood glucose. It should be noted that the daily intake of carbohydrates should not be less than 150g three days before the glucose tolerance test, and at least 8~12 hours of fasting should be taken before the test to ensure that the patient is not in a state of stress, such as infection, trauma, or surgery, so as to ensure the accuracy of the test results. Patients who need to do glucose tolerance test should be under the guidance of a doctor.