It makes sense: Protein breaks down slower than carbs, so it helps you to feel fuller for longer. Eating enough protein helps you to lose less muscle as you shed weight, which keeps your metabolism humming. Plus, focusing on protein can automatically lead to you swapping junkier processed carbs for healthier options such as lean meat, dairy, nuts, seeds, and legumes.
That said, there is such a thing as too much protein. One large study published in 2015 in the journal Clinical Nutrition found that people whose diets were made up of more than 20 percent protein—especially animal protein—were significantly more likely to gain more than 10 percent of their body weight compared to people whose diets had less than 15 percent protein. And while plenty of other research suggests that you can (no, make that should) go higher in protein to lose, not gain, this study was enough to make us scratch our collective heads.
“I think people don’t understand that protein still has calories,” says Bonnie Taub-Dix, R.D., creator of BetterThanDieting.com and Read It Before You Eat It. ” And, no matter how much protein you’re eating, consuming more calories per day than you burn off will always lead to weight gain, adds Emily Kyle, R.D.