U of I study challenges meat-muscle theory

Axios

27-05-2025

Vegan protein can work just as well as animal protein when it comes to muscle building, according to a recent University of Illinois study.
Why it matters: The research appears to upend long-held beliefs, based on lab studies of subjects who ate whey protein versus soy or other plant-based proteins, that animal protein offers the best path toward muscle building.
What they're saying: "We hypothesized that animal protein would be greater than vegan, and protein distribution (meaning meal timing) would matter," Nicholas Burd, researcher and director of the UIUC Nutrition and Exercise Performance Group, tells Axios.
"But as the paper showed, our findings are in contrast to our hypotheses."
Methodology: Burd randomly assigned 40 young adult participants to eat vegan or omnivore meals for nine days.
They engaged in three weightlifting sessions over the nine days and at the end of the trial, researchers biopsied participants' muscles to track "protein synthesis" and observed no significant differences.
Zoom in: Burd also had subjects eat their meals at different times to see "if frequent and smaller meals are better for muscle building than eating two small ones and a big one at the end of the day."
The result: Also no difference.
The change: This U of I study looked beyond the effects of isolated protein sources by giving participants whole meals that, for instance, paired beans with rice, creating "a complete protein." Burd thinks this likely contributed to the surprising results.
The big takeaway: "Achieving a high-quality protein meal that supports the muscle-building response in response to weight lifting can be achieved via different ways," Burd says.
"Including animal protein foods into the meal is easier to achieve a high-quality protein meal, but vegan approaches can be effective too, especially when using complementary protein pairings to balance the amino acid profiles."
The intrigue: The research was sponsored by the beef industry-funded marketing and research program known as The Beef Checkoff. But Burd says his funders didn't try to influence the outcome.
"The Beef Checkoff is committed to educating the consumer regardless of the outcome, but I'd assume they expected a different outcome because our findings are in contrast to what we originally hypothesized. That's the beauty of science … the conviction for a hypothesis doesn't dictate whether it's true or not."