Does the source of protein — plant or animal-based — make any difference to muscle gain? The answer is no, researchers said on Monday, adding that being omnivorous or vegan makes no difference to muscle building after weight training.
Additionally, a team from the University of Illinois at Urbana-Champaign in the US refuted two further claims regarding whether total daily protein intake is evenly distributed throughout the day and whether a moderate but sufficient daily protein intake influences these variables. Their findings are reported in the journal Medicine and Science in Sports and Exercise.
“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 studies that took muscle biopsies after a single feeding found that an animal-based meal provided a greater stimulus for muscle protein synthesis than a vegan meal.
“But measurements taken after a single meal might not reflect the effects of consuming a balanced vegan diet over time,” Burd argued.
For the new study, the team recruited 40 healthy, physically active adults aged 20-40 years.
The participants underwent a seven-day “habituation diet” to standardise their nutritional status before the clinical trial. They were then randomly assigned to either a vegan or an omnivorous diet.
Roughly 70 per cent of the protein in the omnivorous meals was obtained from animal sources, including beef, pork, chicken, dairy, and eggs. The vegan diet balanced the amino acid content of the meals, ensuring that participants consumed complete proteins.
All participants engaged in a series of muscle-strengthening activities in the lab every three days.
Burd was initially surprised to find that there were no differences in rates of muscle protein synthesis between those following vegan and omnivorous diets.
He was also surprised to see that protein distribution throughout the day did not affect the rate of muscle building, given the results from past studies on acute responses to dietary interventions and weight training.
“It was thought that it was better to get a steady-state delivery of nutrients throughout the day,” he said. “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 says, if anyone asks him what’s the best type of food they should eat for muscle building, he’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 doesn’t make a difference.”
–IANS
