How Long Can Humans Survive Without Food? What Happens to the Body Over Time

Can survive for a few weeks

After the second day, the body’s glycogen reserves are completely used up. It then turns to its fat stores for energy. In medical terms, this stage is called ‘ketosis’. The liver breaks down these fats and converts them into ‘ketones’. These ketones travel through the blood and provide an alternative fuel to the brain and heart. Depending on the amount of body fat, a person can live for weeks without food. But remember, while you can survive without food for a while, it’s very difficult to live for more than 3 to 5 days without ‘water’.