New York: Turns out, whether you're an omnivore or a vegan, your muscle-building potential isn’t determined by the source of your protein, but by how and when you fuel your body after exercise.
A study from the University of Illinois at Urbana-Champaign has debunked the longstanding belief that animal-based proteins are superior for muscle building, showing that both omnivorous and vegan diets can be equally effective after weight training.
Published in the journal Medicine and Science in Sports and Exercise, the study challenges several common claims about protein intake and its impact on muscle growth.
"The longstanding belief or the current dogma was that animal-based protein sources were better, particularly for the muscle-building response," said Nicholas Burd, a professor of health and kinesiology at the University of Illinois Urbana-Champaign.
Previous research, which focused on muscle biopsies taken after a single meal, suggested that animal-based proteins provided a stronger stimulus for muscle protein synthesis than vegan meals.
However, Burd argues that these measurements don’t reflect the long-term effects of a balanced vegan diet. “But measurements taken after a single meal might not reflect the effects of consuming a balanced vegan diet over time,” Burd explained.
For this study, the team recruited 40 healthy, physically active adults aged 20 to 40. Participants first underwent a seven-day "habituation diet" to standardize their nutritional status before being randomly assigned to either a vegan or omnivorous diet.
The omnivorous diet included about 70 percent animal-based protein sources such as beef, pork, chicken, dairy, and eggs, while the vegan diet ensured the consumption of complete proteins by balancing the amino acid content of meals.
All participants engaged in muscle-strengthening activities every three days. Surprisingly, Burd and his team found no difference in muscle protein synthesis rates between those following a vegan or omnivorous diet. "I was surprised to see that there were no differences in rates of muscle protein synthesis between those eating vegan or omnivorous diets," Burd admitted.
The researchers also investigated whether evenly distributing protein intake throughout the day had any effect on muscle-building rates. Previous studies had suggested that spreading protein consumption throughout the day would enhance muscle gain.
However, the new study found no such effect. Burd remarked, “It was thought that it was better to get a steady-state delivery of nutrients throughout the day. 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.”
Now, Burd's conclusion is clear: "If anyone asks me what’s the best type of food they should eat for muscle building, I’ll tell them: It’s the kind you put in your mouth after exercise. As long as you’re getting sufficient high-quality protein from your food, then it really doesn’t make a difference."
This study shifts the focus away from protein source and distribution, emphasizing the importance of overall protein quality and sufficient intake post-workout for effective muscle building.