Cutting Meat Without Cutting Muscle

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Can you get just as ripped eating edamame, almonds, peanut butter, and black beans as you could consuming meat and dairy? Experts have long grappled with whether plant-based proteins build as much muscle mass and strength as animal sources. But according to a new study published in the American Journal of Clinical Nutrition, you can definitely get lean and strong without relying on steak, chicken, or chalky whey protein shakes.

To discover this, researchers from the University of Massachusetts Lowell analyzed health data and dietary surveys from almost 3,000 adults. Along with tracking total protein consumption, they teased out where the majority of each person’s protein intake came from. Based on the patterns that emerged, the researchers categorized people into six different groups reflecting their predominant protein source: fast food and full-fat dairy, fish, red meat, chicken, low-fat milk, or legumes.

Next, they evaluated everyone’s lean muscle mass and quadriceps strength. As expected, those who consumed more total protein had more lean muscle mass and stronger quads than those who didn’t get enough of this nutrient in their diet. However, there was no difference in these measures from one protein type to another. In other words, those who got most of their protein from legumes had just as much muscle mass and strength as those whose intake came mainly from meat or dairy.

Keep in mind, though, that not everyone in the legumes group was a vegetarian. “These people were likely getting protein from meat and dairy products as well,” says Kelsey Mangano, lead study author and assistant professor of biomedical and nutritional sciences at UMass Lowell. “It’s just that most of their daily protein came from legumes.” That shows, yet again, that a plant-centric diet with some meat and dairy peppered in is a very healthy way to go.

Mangano was surprised to find that protein type doesn’t matter in terms of muscle mass and strength, and she’s unclear why this is. Protein sources vary in their amino acid profiles and digestibility, and you’d think that would have some impact on their effectiveness. That’s what protein powder brands bank their “We’re the best” claims on, anyway. But based on these results, Mangano suspects that if you get enough total protein in your diet — as 82 percent of study participants did — then differing amino acid compositions and bioavailability may not factor in as much. But if you’re lacking in protein, then these characteristics might matter, she says.

Even if all protein types have the same effect on your muscles, don’t forget that the foods and beverages they’re packaged in are not nutritional equals. “Choose protein sources that fall within an overall healthy diet,” Mangano says. “That means low in saturated fat, low in sodium, not overly processed. Healthy proteins not only benefit muscle health but also help prevent chronic diseases such as heart disease and diabetes.”

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