You Need to Eat More Protein to Lose Weight, Study Says

Obesity has never been a bigger problem in the U.S. than it is right now. At the same time, a recent study indicates that more Americans are on diets than ever before. Could it be that notwithstanding our best intentions, we've been dieting wrong?

As a matter of fact, that's precisely what a team of scientists out of the Alberta Diabetes Institute at the University of Alberta is suggesting. Their new study, published in The American Journal of Clinical Nutrition, suggests that while we've been busy struggling to subsist on the high-fat keto diet and shunning meat to go plant-based, what we really need to eat if we want to lose weight is… more protein. (Related: 15 Underrated Weight Loss Tips That Actually Work.)

The scientists, led by University of Alberta professor, Carla M. Prado, Ph.D., were aware that "total diet replacements" (short-term diets consisting solely of nutritionally complete meal replacements) can be an effective weight-loss strategy for people with obesity and obesity-related conditions such as type 2 diabetes. They also knew that diets emphasizing protein can support weight management through increased energy and feelings of satiety. What they didn't know was how these two diet concepts might work together for healthy normal-weight adults.

The scientists recruited 44 healthy normal-weight adults between the ages of 18 and 35 (19 females and 24 males) to spend 32 hours in a metabolic chamber (a sealed room that measures oxygen, carbon dioxide, and nitrogen, among other things, to provide a highly detailed look at metabolism). The scientists then randomized the subjects into two groups, and fed them as follows:

Half were fed a high-protein total diet replacement (35 percent carbohydrates, 40 percent protein, and 25 percent fat).
Half were fed a diet meant to approximate what the study authors referred to as the "standard North American dietary pattern" (55 percent carbohydrates, 15 percent protein, and 30 percent fat).

Perhaps most importantly, however, both groups were fed the same number of calories.

As it turned out, despite having consumed the same number of calories, the two groups differed significantly in terms of how what they consumed impacted their metabolism. The high-protein group's metabolic readings showed higher levels of energy expenditure and fat oxidation (two indicators of weight loss) than the other group. In other words, it appears the high-protein diet was more effective at inducing weight loss.

And so it appears that eating more protein could be the key to unlocking weight loss, at least among healthy, non-obese adults. More research is needed as to the long-term effects of high-protein diets and how these results might translate to adults with obesity, Dr. Prado told Science Daily. However, this study should help scientists to better understand the effects of high-protein diets while adding to the discussion that "a calorie is not just a calorie."

Here are 29 of the best sources of protein for weight loss. In case you've gone plant-based, here are 26 of the best vegetarian sources of protein.

To get all the latest diet and weight loss news delivered directly to your inbox every day, be sure to sign up for our newsletter.