You may eat a normal diet the night before the glucose test without making any deliberate changes and maintain your normal activities. Fasting for 8 to 10 hours before the test. Glucose tolerance test is a glucose loading test to understand the function of pancreatic B-cells and their ability to regulate blood glucose. Three days before the glucose tolerance test, you can eat and drink normally, keep your daily diet without changing it, and maintain your normal activities. Maintain sufficient fasting time (8~10 hours) the night before. Avoid mental stimulation during the test, no smoking, coffee, tea or food throughout the test, and no strenuous exercise. People who need a glucose tolerance test should cooperate with the test procedure and consult their doctor for specific precautions.