British and Dutch researchers whipped air into a specially formulated drink mixture designed to puff up and stay puffed once swallowed. Compared to a control drink that had the same amount of protein, calories, and other nutritional components, the foamy concoction left people feeling roughly twice as full. Even four hours later, the foam drinkers felt more satisfied than people who gulped the control drink. MORE: 5 Surprising Reasons Your Weight Loss Has Come To A Screeching Halt Like swallowing bubbles, the aerated foam drink appeared to “stretch” the study participants’ stomachs, says study coauthor Luca Marciani, PhD, a gastrointestinal researcher at the University of Nottingham in the UK. Marciani and his colleagues measured the stomach stretching using MRI, and said the foam also swelled the drinkers’ stomachs longer than the normal drink. This extended stretching could explain the drop in hunger, he says. At the same time, Marciani says he can’t rule out the brain’s role in his experiment. The foam drink looked bigger and required more “gulping” than the non-aerated drink—cues that may have fooled the study participants’ brains into believing they’d swallowed more food. (Past research has shown taking tiny bites and eating from heavy dishes can fool the brain in similar ways, cutting your calorie intake up to 21%.) While the drink used in the experiment isn’t available to consumers, scientists from the food giant Unilever contributed to the study and helped concoct the foam drink—meaning that if more research backs up the power of foams to help you feel full from fewer calories, you can bet aerated products will float onto market shelves in the near future. In the meantime, you can take advantage of anaturally puffed-up diet food: popcorn. Besides the filling puffy factor, kernels air-popped on your stovetop contain more antioxidants than fruit and vegetables. Plus, a 2012 study in Nutrition Journal found popcorn is roughly 10-times more filling than other snack foods; the study’s authors say the popping process creates a “foam-like” infusion of air that gives popcorn volume without adding calories. Kernel power! MORE: 6 Ways To Stop Overeating