am not a doctor, but I can share with you some basic physiological and medical knowledge to help you understand the complexity of this issue. It should be emphasized that the following information is for reference only. The specific situation varies depending on many factors such as human physique, health status, environment, etc. If you have any health plan, be sure to consult a professional doctor or nutritionist first. 1. Body energy source and starvation process In the absence of food, the human body mainly relies on glycogen stored in the body (mainly in the liver and muscles), fat and protein to maintain energy supply. In the first few days, the glycogen in the body is gradually depleted, and then the body fat begins to break down to produce ketone bodies as an energy source. This process is called ketosis, but if it lasts too long, the body will also begin to break down protein in the muscles. Although "water fasting" can be carried out more safely in some controlled medical environments, long-term lack of intake of essential nutrients (such as vitamins, minerals and proteins) will not maintain a healthy state no matter how the body regulates. 2. The difference between "maintaining health" and "survival" There may be people who survive for a long time without eating only water (recorded cases of fasting may reach weeks or even longer), but this does not mean that the body is maintained in a healthy or normal state. In the short term (e.g. 1-3 days), some healthy adults may not experience severe discomfort, but you may experience symptoms such as dizziness, fatigue, palpitations, and inattention; and for a longer period of time (e.g. more than a week or even two weeks), the body may have more serious problems due to malnutrition, such as decreased immunity, arrhythmia, electrolyte disorders, impaired organ function, etc. 3. Individual differences and specific risks Everyone's basal metabolic rate, weight, body fat reserves and health level are different, so there is no uniform number for "how many days of health maintenance". For example, for people with more body fat reserves, good diet and good health, short-term fasting may cause relatively mild discomfort; but for people with relatively less nutritional reserves or chronic diseases, even not eating for a few days may cause serious problems. 4. Clinical and medical practice In some clinical settings, strictly designed and monitored "water fasting" or "hunger fasting therapy" may last for several days or even longer, but this practice is carried out under the close supervision of medical staff, and electrolytes, blood sugar and other vital signs are monitored at any time to ensure intervention when necessary. It is very dangerous to try to drink only water for a long time without eating, and it may cause irreversible health damage. Summary: If you ask "how many days can you stay healthy without eating and only drinking water every day", the answer is not a fixed number, because: • Short-term (1 to 3 days) may not usually cause serious long-term health damage, but discomfort symptoms will appear. • Long-term (more than a week) is prone to malnutrition, metabolic imbalance and other serious health problems. Therefore, if you have any thoughts about fasting or other extreme diets, be sure to consult a professional medical staff first to ensure that it is done under safe and monitored conditions. Maintaining a balanced diet and adequate water intake is the best way to maintain long-term health.