How Long Can You Live Without Food?

Your body is very resourceful. When you go without food, your body can obtain energy and fuel from its own fat. If needed, it can also use muscle stores.

After 1 Day: After 1 day without food, your body releases a hormone called glucagon. This hormone tells your liver to make glucose. This glucose is used mostly to feed your brain.

After 2 or 3 Days: After 2 or 3 days without food, your body starts to break down fatty tissue. Your muscles use the fatty acids created during this process as their main source of fuel.

After 7 Days: When the fatty acid reserves are gone, the body switches to protein. By one week, however, the bodies of most starving people will be actively breaking down muscle in order to obtain protein.

After 14 Days: As the breakdown of muscle speeds up, the body begins to lose heart, kidney, and liver function. This is what may ultimately lead to death. Because a starving body lacks the resources to stay healthy, infection is another possible cause of death.