Food can directly affect postprandial blood sugar, so fasting blood sugar should be measured for at least 8 hours. If blood is drawn at 7: 00 in the morning to test fasting blood sugar, you can't eat any snacks, fruits or drinks before 10 the night before, but you can drink a little boiled water during this time. It's best to finish dinner before 8 pm, and don't eat snacks after dinner.

Diet has a great influence on blood lipids. Within 6 hours after eating fatty food, the blood triglyceride concentration will continue to rise, and then gradually fall back to a stable state after 6-8 hours. Therefore, the blood lipid test needs fasting 12- 14 hours.