New York– Whether your protein comes from plants or animals, it makes no difference when it comes to building muscle after weight training, according to a new study from researchers at the University of Illinois at Urbana-Champaign.
Published in the journal Medicine & Science in Sports & Exercise, the study challenges the long-held belief that animal-based proteins are superior for muscle growth. The research also disputes two other common assumptions: that protein must be evenly distributed throughout the day for optimal results, and that moderate but sufficient daily protein intake might influence muscle gains differently based on diet type.
“The longstanding belief has been that animal-based protein sources are more effective, particularly in stimulating muscle-building,” said Dr. Nicholas Burd, professor of health and kinesiology at the University of Illinois. “But that assumption didn’t hold up when tested over time with consistent training and balanced nutrition.”
Previous studies typically measured muscle protein synthesis after a single meal, which often showed animal protein as more effective. However, Burd explained that such short-term data doesn’t account for the cumulative effects of a well-balanced vegan diet.
To test this, researchers recruited 40 healthy, physically active adults between the ages of 20 and 40. Participants first completed a seven-day standardized “habituation” diet to level their nutritional baseline. They were then randomly assigned to follow either a vegan or omnivorous diet, both designed to provide complete proteins and adequate amino acid profiles.
In the omnivorous group, approximately 70% of protein came from animal sources such as beef, pork, chicken, eggs, and dairy. The vegan group received all protein from plant sources, carefully planned to ensure nutritional completeness.
Both groups participated in muscle-strengthening exercises every three days during the trial. At the end of the study, researchers found no significant differences in muscle protein synthesis between the two groups.
“I was surprised,” Burd admitted. “Given past results from short-term studies, I thought we might see a benefit in spreading protein intake more evenly throughout the day, especially with lower-quality proteins. But we found that it doesn’t matter—as long as your overall protein intake is sufficient and of high quality.”
The study ultimately found that both the timing and the source of protein had no measurable effect on muscle growth when dietary needs were met and resistance training was consistently performed.
So what’s Burd’s advice for anyone wondering what to eat to build muscle?
“It’s the food you eat after you train that matters most,” he said. “As long as you’re getting enough high-quality protein—plant-based or animal—it really doesn’t make a difference.” (Source: IANS)
