Adding a sugar-sweetened beverage to a protein-rich meal decreased fat use and diet-induced thermogenesis by more than 40% in people.

The study involved participants that spent 24 hours in a metabolic chamber on two separate occasions. The metabolic chamber allows for the quantification of metabolism including oxygen consumption, carbon dioxide production, and urinary nitrogen excretion.

The participants ate the exact same meals and either had a sugar-sweetened drink or an artificially sweetened drink with the meal. In addition to the 40% decrease in metabolism, the sugary beverage also caused a 40-kcal surplus independent of how much protein was in the meal.

This study suggests that reduced metabolic efficiency after drinking a sugar-sweetened beverage can lead to a greater tendency to make and store fat.