Do not eat as much as possible in the evening 1 day before the blood draw. If the requirement is to draw blood on an empty stomach, for example, to check liver function, kidney function, blood sugar, electrolytes, lipids and other indicators, the requirement for fasting is still relatively strict. Generally, after 10 o’clock in the evening of the previous day, you should not eat or drink until 6 o’clock in the morning when the blood is drawn, at least 8 hours of fasting is required to ensure that the indicators measured by the blood are of reference value. In addition, some indicators do not require fasting, such as endocrine hormones, thyroid function, tumor indicators, etc., do not require fasting, and eating something the night before does not have much effect on the results of the second day.