Incorporating air into foods puffs them up. “Because airy foods are bigger, they trick your brain into thinking you’re eating more,” says Barbara Rolls. The proof: researchers at Penn State University gave volunteers a similar-size snack of dense Cheetos Crunchy or more voluminous Cheetos Puffs. Those who munched on the puffs ate 70 fewer calories even though they polished off 73 percent more by volume. When possible, opt for airy eats: Cheerios over granola, bread over crackers and tubular pasta like rigatoni in place of spaghetti.