So what’s actually going on inside the body during these five days with slightly less food?

When the body receives less energy than usual, it starts shifting from its everyday “growth mode” into something closer to repair mode. This shift activates a number of fascinating biological processes that scientists have been studying intensely over the past decade.

One of them is autophagy — a natural cellular clean-up system. The word literally means “self-eating,” but don’t worry, it’s a good thing. During autophagy, the body begins breaking down and recycling old or damaged cellular components, including proteins and fragments of DNA that are no longer functioning properly. Think of it as a kind of spring cleaning at the cellular level.

At the same time, certain signals that normally promote constant growth and cell division temporarily quiet down. This allows the body to focus on maintenance and repair instead.

Research also suggests that once the fasting period ends and normal eating resumes, the body may stimulate the production of new stem cells, helping to regenerate fresh, healthy cells in different tissues.

In other words: a short period of eating less may give the body a chance to clean house, reset, and rebuild — which is why fasting and fasting-mimicking diets have attracted so much interest from researchers around the world.