As Anne Alexander explains in The Sugar Smart Diet, a lifetime of overdoing it on sugar may eventual show up on your face in the form of early wrinkles. The culprit is the natural process called glycation, where sugar in your bloodstream attaches to proteins to form harmful new molecules called advanced glycation end products, known in short, ironically, as AGEs. Eating more sugar—straight up added sugars like the tablespoons you dump into your coffee every morning, or secret sugars hiding out in "healthy" salad dressing and sweeter-than-candy-bar yogurt—causes more AGEs to build up and beat up nearby proteins.
"Most vulnerable to damage are the protein fibers collagen and elastin, which keep skin firm and elastic," Alexander writes in The Sugar Smart Diet. "Once they're damaged, these fibers go from springy and resilient to dry and brittle, leading to wrinkles and sagging. These age-related changes to the skin start at about age 35 and increase rapidly after that, according to a study published in the British Journal of Dermatology."