A new study published in the journal Medicine & Science in Sports & Exercise has found that there are no differences in rates of muscle protein synthesis between those eating vegan and omnivorous diets.
The study was led by Nicholas Burd, a professor of health and kinesiology at the University of Illinois Urbana-Champaign, with former graduate student Andrew Askow. Through a nine-day diet and weight training regimen, the research concluded that protein source does not make any difference to muscle gain. Furthermore, it did not matter whether protein intake was distributed throughout the day.
Methodology
As part of the study, 40 healthy, physically active 20 to 40-year-old adults were recruited and placed on a seven-day “habituation diet” to standardize their nutritional status. They were then randomly assigned to either a vegan or an omnivorous diet. All meals were provided by the research team.
In the omnivorous meals, almost 70% of protein was obtained from animal sources. The vegan diet balanced the amino acid content of the meals to ensure participants consumed complete proteins.
Both groups were divided again into those who ate roughly the same amount of protein at each of three meals and those whose protein intake varied across five meals, weighted more toward the end of the day. All participants engaged in muscle-strengthening activities in the lab every three days, and wore accelerometers to track their activity levels when not in the lab.
The participants drank “heavy” water — labeled with deuterium, a stable isotope of hydrogen — every day. The deuterium atoms exchanged with hydrogen atoms within amino acids to make them heavy, serving as tracers that allowed the researchers to track their incorporation into muscle tissue. Tissue biopsies from a leg muscle were taken at the beginning and end of the trial.
Protein distribution does not matter
The scientists were surprised to find that neither diet nor protein distribution across the day had any effect on muscle synthesis. Despite this, research indicates that just 57% of Americans believe it is possible to build muscle on a plant-based diet, while 87% think consuming animal products is important for obtaining sufficient protein. This highlights the need for more education about nutrition.
“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.”
