Losing weight isn’t easy. But what’s even more difficult is trying lose fat while building muscle mass. Think: losing belly fat to reveal cut abs. According to new research, protein may be the key to this seemingly elusive goal.

Researchers at McMaster University in Canada have recently uncovered another benefit of protein, according to a study published in The American Journal of Clinical Nutrition. Forty overweight, but recreationally active men were recruited for the study. They followed a reduced-calorie diet in which they ate about 40 percent of their normal diet and were randomly assigned to either a low-protein or high-protein group. Participants also cut their daily calories by almost half (about a 1,000-calorie deficit.

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The low-protein group ate a little more than the recommended dietary allowance (RDA) for protein—about .36 grams for every pound of body weight (roughly 70 grams), while the high-protein group ate around three times the RDA—1 gram for every pound (roughly 200 grams). The researchers provided all meals and drinks with the exception of water and zero-calorie drinks. Both groups were given beverages with whey protein to drink during the day and one to drink immediately following exercise at the research lab, in order to assure consistent type and timing of protein intake between the groups. All participants came to the lab six days a week for strenuous exercise training, including combinations of full-body resistance circuits, high-intensity interval training, sprint interval training, and stationary bike riding.

After the month-long trial period, researchers found both groups lost the same amount of weight and improved their physical fitness. But the type of weight loss between the two groups was different.

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The high-protein group gained 2.5 pounds of muscle and lost more fat (10.5 pounds), compared to the low-protein group, which lost eight pounds of body fat, and did not gain any muscle. This suggests that a high-protein, low-calorie diet in combination with exercise leads to weight loss and an increase in muscle mass.

Lose Fat, Gain Muscle

Get your protein fix

Fish, tofu, eggs, chicken breast, beans, and nuts are great sources of protein to add to any meal. Even if you’re a vegetarian, there are plenty of plant-based foods that are high in protein.

Embrace dairy

Nonfat or low-fat yogurt and milk are loaded with protein and other beneficial nutrients, such as calcium and vitamin D. Some studies show that routine dairy intake may help with weight loss and weight management.

Keep calories in check

Track your daily intake to make sure you’re not overeating (little things add up quickly). Try logging your nutrition with an app like MyFitness Pal or in an old-fashioned journal.

Vary your exercise routine

Try an exercise circuit one day and go for a run another day to help build different muscles. Switching up your routine actually may lead to greater calorie burn by keeping your muscles guessing.

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