Generally speaking, you can go without food and only drink water every day for several days, but this is extremely harmful to your health, and the specific duration varies from person to person, usually about 3-7 days. The following situations may occur: - **Physiological changes** - **Lower blood sugar**: After being hungry for several hours, blood sugar levels will gradually decrease, and the body's energy supply will be insufficient, leading to symptoms such as dizziness, fatigue, palpitations, and hand tremors. - **Metabolic slowdown**: In order to reduce energy consumption, the body's metabolic rate will drop significantly, which not only affects the normal function of various organs, but may also cause fat accumulation when eating again later. - **Muscle decomposition**: The body will begin to break down muscles to obtain energy, resulting in a decrease in muscle mass, strength and athletic ability. - **Malnutrition**: Lack of food intake, severe lack of nutrients such as vitamins, minerals, and proteins, affecting the body's normal physiological functions, such as reduced immunity, anemia, skin problems, etc. - **Organ function damage** - **Digestive system**: Slow gastrointestinal motility and reduced secretion of digestive juices may cause problems such as indigestion, stomach pain, constipation or diarrhea, and may cause gastritis, gastric ulcers and other diseases in the long term. - **Kidney**: Reduced excretion of metabolic waste from the body increases the burden on the kidneys, which can easily lead to kidney damage and, in severe cases, renal failure. - **Heart**: May cause heart problems such as arrhythmia and decreased myocardial contractility, increasing the risk of cardiovascular disease. Drinking only water without eating is a very unhealthy behavior that can cause serious damage to the body and even endanger life. Do not try it. If you want to improve your health or manage your weight by controlling your diet, you should adopt a scientific and reasonable approach and seek guidance from professionals when necessary.