Three days without food can cause malnutrition, lead to stomach disorders and increase the risk of gallstones. 1. Malnutrition: three days without food can easily cause malnutrition, unbalanced nutritional intake, such as iron, vitamin B12 and other intake is insufficient, but also cause hypoglycemia, fatigue, dizziness and other uncomfortable symptoms. 2. lead to gastric diseases: three days without eating, the secretion of gastric acid will produce stimulation of the gastric mucosa caused by gastric distension, acid reflux and other symptoms, the duration of a longer period of time, it is easy to cause chronic gastritis, gastric ulcers and so on. 3. Increase the risk of gallstones: three days without eating, long time to keep hungry, bile can not be discharged and silt in the gallbladder will form gallstones. Three days without food is harmful, in order to timely detection of digestive diseases, it is recommended to do regular physical examination, found early formal treatment.