The term “autophagy” is composed of the Greek words for “self” (auto) and “eat” (phagein) and means the renewal of old cells. Intermittent fasting reinforces this natural process of the body, which starts about 12-14 hours after the last meal. During autophagy, the body uses the components of old, damaged and no longer usable cells to build new, healthy cells. Pathogens are also fought and the immune system is additionally activated. Autophagy is therefore a kind of endogenous waste disposal and recycling system.