It’s a common scenario: you get in a protein-rich meal post-training – but then follow it with a sweet soft drink for a pick-me-up. That cardio finisher was hard, right?

However, a new study in BMC Nutrition found this pairing isn’t ideal. Having a protein-rich meal with a sugar-sweetened drink can decrease your fat-burning ability by 8%.

FYI: that’s not just soft drinks, but any of those sneaky sugar traps, like energy drinks and many iced-teas, for example.

The study tested the effect of pairing sugar-sweetened drinks with a 15% protein meals and 30% protein meals. All the meals had the same amount of fat and kilojoules. Researchers found that if the sugar-sweetened drink was consumed with the 15% protein meal, fat oxidation decreased by 7.2g. If drunk with a 30% protein meal, it decreased by 12.6g. Ie, all your good work pumping up that protein goes to waste when sipping on a sweet 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,” says Dr Shanon Casperson, lead author of the study. “This decreased metabolic efficiency may ‘prime’ the body to store more fat.”

Another downside: the combo of sugary drinks and high-protein meals increased the study participant’s desire to eat savoury and salty foods for four hours after eating. Come at us corn chips!

The researchers found it wasn’t just about having extra kjs in your day – the drinks had flow on effects for your body. “Our findings suggest that having a sugar-sweetened drink with a meal impacts both sides of the energy balance equation,” says 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.”

So, fat-burning is your goal, it’s time to kiss the sweetened drinks goodbye. Sad face.