If you’ve ever been told you have to eat meat to build muscle, science just called your bluff. A new study published in Medicine and Science in Sports and Exercise suggests that when it comes to building muscle, a well-planned plant-based diet works just as well as an omnivorous one. Also surprising? Timing your protein intake throughout the day didn’t really matter either.
That’s right—whether you’re getting your gains from tofu or turkey, or whether you’re spreading your protein evenly across meals or loading it up at dinner, your muscles probably won’t care—as long as you’re getting enough.
“The longstanding belief or the current dogma was that animal-based protein sources were better, particularly for the muscle-building response,” said author, Nicholas Burd. “And so, our general hypothesis based on these previous studies was that the animal-based eating pattern would be more effective at supporting the muscle-building response.”
But that assumption, it turns out, was based mostly on short-term studies—single meals, single workouts. Burd and his team wanted to know what happens in real-world conditions, where diets vary, meals are spread out, and workouts span weeks.
The Study: Meat vs. Plants, Even Protein vs. Uneven
Burd’s team recruited 40 healthy, physically active adults aged 20 to 40, and gave them a week-long prep diet to standardize their nutrition. Then, they were assigned to one of two diets:
- A plant-based diet, rich in whole, plant-based foods with amino acid profiles carefully balanced
- An omnivorous diet, where 70% of the protein came from animal sources like chicken, eggs, dairy, and beef
Each diet group was then split again:
- One subgroup ate protein evenly distributed across three meals
- The other had uneven protein intake spread across five meals, heavier toward the end of the day
All participants trained with weights every three days and wore accelerometers to track physical activity outside the lab. To measure muscle growth at a cellular level, they drank “heavy water” (water tagged with deuterium), which helped scientists track how protein got built into muscle tissue over the nine-day study. Muscle biopsies were taken at the beginning and end.
It All Worked Equally Well
Despite decades of claims that animal protein is king, Burd’s team found no significant difference in muscle protein synthesis between fully plant-based-eaters and meat-eaters.
“It was thought that it was better to get a steady-state delivery of nutrients throughout the day,” said Burd.“I also thought that if you’re getting a lower-quality protein—in terms of its digestibility and amino acid content—that perhaps distribution would make a difference. And surprisingly, we showed it doesn’t matter.”
Even more surprising, protein timing didn’t make a difference either. Those who spread their protein evenly saw the same muscle-building response as those who ate more protein later in the day.
What This Means for Your Post-Workout Plate
“Sufficiency” is key. The study participants consumed 1.1–1.2 grams of protein per kilogram of body weight per day, which Burd notes is in line with typical diets. Going way beyond that doesn’t necessarily build more muscle, either—a previous study from his lab found that extra protein above that range didn’t boost gains.
Bottom Line
The study powerfully overturns prior ideas that only eating meat will lead to muscle gains and is healthier. Instead, it highlights two very important points:
- It is more important to get adequate amounts of protein throughout the day. Those who are on a plant-based diet or are vegan can easily get sufficient amino acids through various foods and/or supplementation (though not required).
- The absolute importance of exercise. Exercise help preserve lean muscle mass and protein wasting. When one exercises, it encourages the muscles to hold on to the protein instead of using it as a source of energy. Therefore, simply eating meat or being on a plant-based diet is not enough. There must be exercise.
But here is the real kicker, now that we know a plant-based diet can help build muscles just as well as an omnivorous ones, compound that with the fact that a plant-based diet significantly improves one’s health in various ways including decreasing the risk of cancer, heart disease, and diabetes, this all together makes the plant-based diet a more superior diet.
AT Askow et al. Impact of Vegan Diets on Resistance Exercise-Mediated Myofibrillar Protein Synthesis in Healthy Young Males and Females: A Randomized Controlled Trial. Medicine & Science in Sports & Exercise (2025). DOI: 10.1249/MSS.0000000000003725
