Fasting diets have been criticized in the past but scientists at the university discovered fasting several days can trigger the body to start producing new white blood cells.

When you starve, the system tries to save energy, and one of the things it can do to save energy is to recycle a lot of the immune cells that are not needed, especially those that may be damaged,” Valter Longo, one of the study’s authors, said.

“What we started noticing in both our human work and animal work is that the white blood cell count goes down with prolonged fasting. Then when you re-feed, the blood cells come back,” Longo said.

More research is needed, but the study suggests fasting could lead to healthier aging, better results from chemotherapy, and could help people with auto-immune disorders.