Dr Shanon Casperson, lead author of the study from USDA-Agricultural Research Service Grand Forks Human Nutrition Research Center, USA said: "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. This decreased metabolic efficiency may 'prime' the body to store more fat."
The researchers found that the inclusion of a sugar-sweetened drink decreased fat oxidation, which kick-starts the breakdown of fat molecules, after a meal by 8%. If a sugar-sweetened drink was consumed with a 15% protein meal, fat oxidation decreased by 7.2g on average. If a sugar-sweetened drink was consumed with a 30% protein meal, fat oxidation decreased by 12.6g on average. While having a sugar-sweetened drink increased the amount of energy used to metabolise the meal, the increased expenditure did not even out the consumption of additional calories from the drink.
Dr. Casperson said: "We were surprised by the impact that the sugar-sweetened drinks had on metabolism when they were paired with higher-protein meals. This combination also increased study subjects' desire to eat savory and salty foods for four hours after eating."
Source: http://www.biomedcentral.com/