A tray of fungi-derived Quorn pieces, a vegan protein sourceShare on Pinterest
When it comes to building muscle, animal protein is not the only option. Simon Dawson/Bloomberg via Getty Images
  • New research has investigated whether a vegan diet with protein sourced from non-animal products could support muscle growth and repair as effectively as a diet that includes animal protein during strength training.
  • The study involved young and healthy adults split into two groups, one consuming a high-protein animal-based diet and the other a high-protein non-animal-based diet.
  • Results showed that both groups gained a similar amount of muscle mass and strength, indicating that a high-protein, non-animal-derived diet can be as effective as a diet that consists mainly of animal-derived protein sources, when paired with resistance training.

New research, published in the Journal of Nutrition, found that fungi-derived mycoprotein (Quorn) is just as effective at supporting muscle building during resistance training as animal protein.

The study included two parts. In the first part of the study, 16 young and healthy adults (eight men and eight women) were split into two groups.

Both groups did leg exercises every day, but one group (named OMNI1) ate a diet with high protein from animal sources while the other group (VEG1) ate a diet with high protein from non-animal sources.

The researchers measured how much muscle protein was made during exercise and at rest.

In the second part of the study, 22 young and healthy adults (11 men and 11 women) did a 10-week leg exercise program five days a week.

Some of them ate a high-protein diet from animal sources (OMNI2) and others ate a high-protein diet from non-animal sources (VEG2).

The research team measured the size of leg muscles, overall body muscle, muscle strength, and function before and after the program and at two and five weeks into it.

During the study, researchers found that exercising the legs increased the rate of muscle protein production by about 12% compared to when the legs were at rest.

Both groups gained a similar amount of muscle mass and muscle fiber size, as well as increased muscle strength in various muscle groups, despite having different protein sources in their diets.

Medical News Today spoke to three independent experts, who were not involved in this research, to hear their perspectives on the study.

Stephanie Wells, a registered dietitian, said, “this paper adds to the growing body of evidence for the ability of some plant-based proteins to support muscle building as effectively as animal proteins like whey.”

However, Wells noted that the study did have some limitations, namely the lack of a control group and the small number of participants.

“Because of these limitations, we can’t know for sure whether or not similar results would be seen for the general population,” Wells noted.

“Since the study was in young adults, we also can’t be sure whether similar results would be seen for other groups like older adults. Race wasn’t reported, so we can’t make conclusions about whether results might vary depending on racial or ethnic background,” she added.

“This study adds to the growing amount of evidence for the effectiveness of plant-based protein for building muscle, although more research with high-quality study designs is needed. It may be encouraging for people who want to eat [fewer] animal products or transition to a plant-based diet for reasons of personal health, the environment, or animal welfare. It may also help dispel the common misconception that plant-based diets can’t provide enough protein for optimal health.”
— Stephanie Wells

Kristen Carli, a registered dietitian nutritionist, agreed, saying “I’m excited to see more research highlighting how effective plant-based protein can be for fueling exercise.”

“Typically, when choosing between plant-based and animal-based protein sources, we often hear the argument that because a plant-based source of protein lacks all of the amino acids, that it is not a ‘complete’ protein source,” Carli explained.

“However, many of these plant-based sources of protein are considered ‘complete’, especially soy, quinoa, or pistachios,” she pointed out.

“I hope that by reading this article or by continuing research in this field, the public will start to understand just how beneficial plant-based protein can be. It’s not just for those that want to be 100% vegan or vegetarian. It’s very possible (in fact, I’d recommend it!) to have several meals throughout the week that are plant-based. However, if you are doing so, be sure to create balanced meals, prioritizing a source of plant-based protein on the plate.”
— Kristen Carli

James Dixon, certified personal trainer and fitness and nutrition expert, told MNT that “the findings of this study are significant because it challenges a commonly held belief that animal protein is necessary for building muscle.”

“The results are promising and make a case for more people to advocate a vegan diet and become meat-free. As I see it, this study also highlights the importance of animal and plant-based protein sources when designing diets for individuals who engage in resistance training,” Dixon said.

“I see a shift in focus on personalized diets rather than the typical belief that vegan diets are more challenging for people building muscles and resistance training,” he said, adding that people who may experience adverse reactions to products like Quorn can seek other protein sources.

“This study will result in interest in more plant-based proteins, and mainstream trends toward no-meat diets may soon be upon us. Apart from mycoprotein, there will be a growing interest in other protein sources, which may also be as effective. [People can] incorporate protein sources like legumes, nuts, seeds, whole grains, vegetables, soy products, or other wheat-based proteins.”
— James Dixon

Although Quorn was used in this research, Dixon pointed out that “certain types of mushrooms or microalgae are being researched as potential plant-based protein sources.”

“Mycelium-based mushroom protein is high in protein and can be grown from agricultural waste,” he said.

“Spirulina and chlorella are being studied as plant-based protein sources. These protein-rich microalgae require little water and area to flourish, making production more sustainable and environmentally friendly,” Dixon highlighted.

Ultimately new protein sources, such as microalgae-based protein products, will continue to be developed, increasing the options available to the general public.

This will make it more accessible for people to incorporate higher amounts of plant-based protein sources into their diet.