Kicking nicotine and avoiding excessive sunlight will help, but the secret to healthy-looking skin is the food you eat. "The wrong choices cause inflammation down to the cellular level," says dermatologist Nicholas Perricone, the author of Forever Young, a book about how eating right can keep you looking younger than your years. "And while you can't see it, that inflammation leads directly to wrinkling, sagging, and premature aging." Here is what to eat to prevent that from happening.