The next time you're in a queue for a burger, perhaps think twice before ordering a large soda. Washing down a high-protein meal with a sugary drink decreases metabolic efficiency, which may prompt the body to store more fat, according to a new study published in the open access journal BMC Nutrition.
We all know that drinking too many sugary drinks is not good for your waistline, your teeth, or the health of many of your organs. But this study appears to show that sugary drinks change how your body breaks down food.
The study by the United States Department of Agriculture (USDA) found that sugar-sweetened drinks with a meal decrease fat oxidation by approximately 8 percent. If the meal in question was 15 percent protein, the sugary drink reduced fat oxidation by an average of 7.2 grams (0.25 ounces). With a 30 percent protein meal, fat oxidation decreased by 12.6 grams (0.44 ounces) on average.
"We were surprised by the impact that the sugar-sweetened drinks had on metabolism when they were paired with higher-protein meals," lead author Dr Shanon Casperson, from the USDA-Agricultural Research Service's Grand Forks Human Nutrition Research Center, said in a statement. "This combination also increased study subjects' desire to eat savory and salty foods for four hours after eating."
"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," Dr Casperson added. "This decreased metabolic efficiency may 'prime' the body to store more fat."
To uncover this, the researchers gathered 27 healthy adults, who were on average 23 years old, and studied them for two 24-hour periods. They spent their 24 hours in a room calorimeter that measured their movement, oxygen, carbon dioxide, temperature, and pressure to determine their energy expenditure and metabolism. On one of the visits, they received two 15 percent protein meals for breakfast and lunch, then two 30 percent protein meals on the other visit.
"Our findings suggest that having a sugar-sweetened drink with a meal impacts both sides of the energy balance equation," added Dr Casperson. "On the intake side, the additional energy from the drink did not make people feel more sated. On the expenditure side, the additional calories were not expended and fat oxidation was reduced."
"The results provide further insight into the potential role of sugar-sweetened drinks – the largest single source of sugar in the American diet – in weight gain and obesity."