A bag of air-popped popcorn could be the perfect snack to stash in your desk drawer. Not only is it filled with fiber, it’s also filled with air. Just like high-volume water-packed foods keep us full, so do light, airy foods, says a research study. Plus, when you choose popcorn you get to do a lot of munching. Three cups of air-popped popcorn serve up nearly 4 grams of fiber and a surprising 3 grams of protein for only 93 calories. Give yours a low-cal flavor blast by sprinkling it with curry powder or cocoa. Or try this yummy idea below.