Fasting refers to the conscious restriction and cessation of eating, or even stopping the consumption of beverages, etc. 1. Clinically, patients are usually advised to fast due to acute pancreatitis, gastrointestinal bleeding, intestinal obstruction, acute cholecystitis or before surgery is needed, but they are all combined with nutritional fluids, electrolytes, etc. to ensure that the body needs energy and maintain vital signs. 2. Prolonged fasting may result in dizziness, hypoglycemia, panic, fatigue, malnutrition, gastrointestinal damage, etc. If fasting for a long period of time at one time, it may lead to anorexia, bulimia, etc., and may even jeopardize life. If it is not necessary, the behavior of blind fasting is not recommended to avoid the impact on health.