A calorie-restricted diet is often said to enhance longevity. Less frequently discussed, and poorly understood, is why fasting should slow aging or delay the loss of tissue function associated with aging. To better understand how fasting confers its putative benefits, MIT biologists studied a kind of tissue renewal, the maintenance of the lining of the intestine. To renew itself every five days, the lining depends on the regenerative capacity of stem cells, which declines as we age.

Fasting, the MIT biologists found, dramatically improves stem cells’ ability to regenerate. In studies of both aged and young mice, the researchers determined that even a 24-hour fast can reverse the age-related loss of stem cell function.

Details of the study appeared May 3 in the journal Cell Stem Cell , in an article entitled “ Fasting Activates Fatty Acid Oxidation to Enhance Intestinal Stem Cell Function during Homeostasis and …