Plant-Based Diets Support Same Level of Muscle Growth as Omnivorous Diets

Regular resistance training, alongside consuming enough protein, results in similar levels of growth in muscle mass and strength, regardless of whether the protein comes from animal or plant sources. This principle was confirmed once again in a recent study published in The Journal of Nutrition that compared the muscle growth of young adults eating high-protein omnivorous diets with others eating high-protein plant-based diets.

The researchers, from the US and UK, tested short-term muscle protein synthesis rates, as well as longer-term muscle adaptations during a 10-week resistance training program, in men and women consuming high-protein diets either from omnivorous or entirely plant-based sources. In order to reach high protein intakes of ~2g/kg/day, the adults assigned to the omnivorous diets supplemented with milk protein, while those eating only plants added mycoprotein – a plant-based, fungal-derived protein source. After 10 weeks of weight training while following their respective diets, they assessed changes in multiple measures of muscle mass and strength.

Both groups experienced the same degree of increase in both resting and exercised daily muscle protein synthesis. Prolonged resistance training also led to increases in muscle size and strength similarly in both groups, with no differences in any variable they measured, including lean muscle mass, muscle volume, muscle fiber cross-sectional area, and one-repetition maximum of multiple muscle groups.

These findings support previous research that also showed similar gains in lean muscle mass and strength whether consuming high-protein plant-based or omnivorous diets, adding yet further support to James Wilks’ quote in The Game Changers film: "And when it comes to gaining strength and muscle mass, research comparing animal and plant protein has shown that as long as the proper amount of protein is consumed, the source is irrelevant."

References

Monteyne, A. J., Coelho, M. O. C., Murton, A. J., Abdelrahman, D. R., Blackwell, J. R., Koscien, C. P., Knapp, K. M., Fulford, J., Finnigan, T. J. A., Dirks, M. L., Stephens, F. B., & Wall, B. T. (2023). Vegan and Omnivorous High Protein Diets Support Comparable Daily Myofibrillar Protein Synthesis Rates and Skeletal Muscle Hypertrophy in Young Adults. The Journal of nutrition, 153(6), 1680–1695. https://doi.org/10.1016/j.tjnut.2023.02.023

Hevia-Larraín, V., Gualano, B., Longobardi, I., Gil, S., Fernandes, A. L., Costa, L. A. R., Pereira, R. M. R., Artioli, G. G., Phillips, S. M., & Roschel, H. (2021). High-Protein Plant-Based Diet Versus a Protein-Matched Omnivorous Diet to Support Resistance Training Adaptations: A Comparison Between Habitual Vegans and Omnivores. Sports medicine (Auckland, N.Z.), 51(6), 1317–1330. https://doi.org/10.1007/s40279-021-01434-9