British journalist and physician Michael Mosley sets an ambitious goal: to become healthier and lose weight while making as few changes as possible to his life. In working toward these goals, Mosley discovers a powerful new science behind the old idea of fasting, a program that still allows him to enjoy his favorite foods. He takes a road trip across the U.S. to investigate how a little hunger can turn on the body’s “repair genes” and, of course, tries the new science himself. Mosley learns that a diet based on feast and famine has powerful effects on the body, reducing the risks of heart disease, diabetes and some cancers. The diet seems to pack the anti-aging clout of calorie restriction while still allowing for a taste of the good life. And it turns out to be not only good for the body; it may also be good for the brain.

• Documentary