Like peas and carrots, peanut butter and jelly, or milk and cereal, it just seems right to pair a big, juicy burger with an ice cold soda (with fries too, of course). Not only is the image so well-preserved in American history that the burger-and-soda combo just feels American, it seems kind of wrong to drink anything else with a burger. Juice? Milk? Weird.
Unfortunately, those two peas in a pod are in cahoots in a way that you’re not going to like. According to a new study published in BMC Nutrition, the simple act of drinking a soda—or any sugar-sweetened beverage, for that matter—with a high-protein food, like a burger or fried chicken, weakens your body’s ability to burn fat. In fact, that sugary soda is actually telling your body where else to store fat—something that wouldn’t happen if you’d eaten that protein-rich meal without the pop.
In the study, 27 healthy adults were placed in isolated “room calorimeters,” specially calibrated to measure how each of their bodies were able to metabolize and break down meals. In one room, participants were served breakfast and lunch that contained 15 percent protein, and a drink that was either sweetened with sugar or artificial sweetener. In another room, participants’ meals contained 30 percent protein and again, either a sugar-sweetened or artificially sweetened drink.
What researchers found was that, when paired with a sugar-sweetened drink, the participants’ fat-burning abilities decreased by an average of 8 percent compared to the artificially sweetened drink. “We found that about a third of the additional calories provided by the sugar-sweetened drinks were not expended, fat metabolism was reduced, and it took less energy to metabolize the meals,” said Dr Shanon Casperson, the paper’s lead author and a researcher at the USDA-Agricultural Research Service Grand Forks Human Nutrition Research Center. “This decreased metabolic efficiency may ‘prime’ the body to store more fat,” she adds.