The main method by which a person obtains energy is by eating, and if no food is taken, the patient may survive for about a week as each patient’s constitution is different. If there are other means of nutritional support, such as a gastric tube, nasoenteric tube feeding or intravenous nutrition, the life span can be prolonged and the recovery of the organism can be promoted. Humans need to expend a lot of energy throughout the day, even when they are not exercising and are lying in bed. The main means for humans to replenish energy is the nutrients in food. If the patient does not eat for a long time, the body can not get energy supplementation, there will be dizziness, fatigue, emaciation and other symptoms, and then the body’s organs began to fail, the body’s immunity is greatly reduced, but also will cause all kinds of complications, so the patient’s survival time may be in about a week. If the patient does not eat and at the same time can not take in water, the survival time will be greatly reduced. Failure to ingest water will cause serious disorders of water and electrolytes in the patient’s body, and the patient can generally survive for only a few days. If you feel unwell, you should go to the hospital in time to avoid delays.