Cocoa hydrates your skin, making it firmer and more supple, Dr. Bank says. "And dark chocolate contains high levels of flavonols, a potent type of antioxidant," adds Nicholas Perricone, MD, a dermatologist in New York City. For maximum flavonol content, eat chocolate that's at least 70 percent cacao. A couple of squares a day should be enough to improve luminosity. "When applied topically, the caffeine in chocolate may temporarily reduce skin puffiness," says Jessica Wu, MD, a dermatologist in Los Angeles.