Study Finds No Difference In Muscle Fiber Protein Synthesis Between Vegan And Omnivore Diets

A new study suggests that there is no difference in the synthesis of muscle fiber protein between those who follow omnivorous and those who follow vegan diets.

This indicates that eating animal products has no inherent benefit for people looking to maximize their muscle gains. The randomized control trial also found that variable protein distribution, quality, and digestibility had no impact on participants’ muscle growth.

The study focused on 40 healthy, physically active adults aged between 20 and 40. After an initial “habituation” diet to standardize their nutrient levels, the participants were assigned either omnivorous or vegan diets. All participants engaged in strength training and tracked their overall activity levels. They also drank deuterium-infused water that allowed the research team to trace consumed amino acids as they were incorporated into muscle fibers.

Participants were then split once again, with some eating a regular amount of protein at each meal and some eating a variable amount. For the omnivores, approximately 70 percent of their protein came from animal-based sources, and the vegans consumed a well-balanced amino acid profile throughout. Leg tissue biopsies were taken at the start and the end.

“The longstanding belief or the current dogma was that animal-based protein sources were better, particularly for the muscle-building response,” explained study lead Nicholas Burd, professor of health and kinesiology at the University of Illinois Urbana-Champaign.

“It was thought that it was better to get a steady-state delivery of nutrients throughout the day,” continued 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.”

Choice of protein ‘really doesn’t make a difference’

Photo shows bowls of ingredients known for their plant-based protein, from lentils and beans to broccoli and tofu — Adobe Stock Plant-based protein is nutritionally comparable to animal products and may have other benefits

The scientific journal Medicine & Science in Sports & Exercise published the new study in April. It followed a previous study by the same team that found protein intakes higher than 1.1g of protein per 1kg of bodyweight per day make no difference to muscle gains while training.

In November, a beef industry-funded study that set out to prove the inferiority of plant proteins instead found that vegan options have the same muscle and health benefits as meat, including when participants relied on so-called “incomplete” protein from bread.

Recent research found that nearly 90 percent of Americans incorrectly believed that meat, dairy, eggs, and other animal products were an important part of getting enough protein. The New York Times previously reported that Americans get around twice the daily recommended amount, something that Harvard Health notes can cause health issues like kidney stones.

Burd said that the best type of food for muscle building is “the kind you put in your mouth” right after doing exercise. “As long as you’re getting sufficient high-quality protein from your food, then it really doesn’t make a difference,” he added.