Going without food for several days does far more than force the body to burn fat. Research published in Nature Metabolism revealed that extended fasting sets off widespread biological changes throughout the body, including shifts linked to the brain, metabolism, and immune system.
Scientists found that many of the most significant effects did not appear right away. Instead, the body seemed to enter a very different biological state after about three days without food.
The findings offer one of the clearest pictures yet of what prolonged fasting does inside the human body at a molecular level. Researchers say the work could eventually help scientists develop treatments that mimic some of fasting's effects without requiring people to stop eating for days.
What Happens to the Body During Prolonged Fasting?
Humans evolved to survive periods of food scarcity. When food is unavailable, the body switches from using glucose from meals to relying on stored fat for energy.
