Interest in vegan diets has increased over the years. With that, some recent research has looked at vegan diets with respect to hypertrophy. A couple of new studies have looked at high-protein (1.6g/kg/day-1.8g/kg/day) vegan diets similar to traditional high-protein omnivorous bodybuilding-type diets. The findings show there is not a statistically significant difference in terms of muscle protein synthesis rates and muscular growth. So, it seems, with the current findings, a vegan diet is a viable option for muscle building phases for those wanting to reduce or eliminate meat and animal protein from their diets.
Before switching, there a few things to keep in mind.
First, in terms of amino acids compositions, animal proteins are generally of higher quality and more complete than plant-based proteins. If a protein contains all of the essential amino acids in sufficient quantities, it is considered to be a complete protein. Many plant proteins are not (some may contain leucine, but may miss other amino acids or vice versa, for example). As there is a lot of variability in protein profiles of vegan sources, a vegan diet may need to include different sources in order to hit getting protein and enough of all essential amino acids and leucine in during the day.
Given that protein quality is a bit lower, generally, for vegan sources, a vegan muscle building diet may want to shoot for the upper end of protein intake (1.6g to 1.8g/kg/day or slightly higher).
Many plant-based protein sources come with carbs (grains) or fat (nuts). So, for the equivalent amount of protein, many vegan protein sources have more calories than say something like a grilled skinless chicken breast. If you are trying to shed fat and get lean, maintaining a high protein vegan diet while dropping calories requires more planning.
Monteyne AJ, Dunlop MV, Machin DJ, Coelho MOC, Pavis GF, Porter C, Murton AJ, Abdelrahman DR, Dirks ML, Stephens FB, Wall BT. “A mycoprotein-based high-protein vegan diet supports equivalent daily myofibrillar protein synthesis rates compared with an isonitrogenous omnivorous diet in older adults: a randomised controlled trial.” Br J Nutr. 2020 Nov 11:1-11. doi: 10.1017/S0007114520004481. PMID: 33172506; PMCID: PMC8110608.
Hevia-Larraín V, Gualano B, Longobardi I, Gil S, Fernandes AL, Costa LAR, Pereira RMR, Artioli GG, Phillips SM, Roschel H. “High-Protein Plant-Based Diet Versus a Protein-Matched Omnivorous Diet to Support Resistance Training Adaptations: A Comparison Between Habitual Vegans and Omnivores.” Sports Med. 2021 Jun;51(6):1317-1330. doi: 10.1007/s40279-021-01434-9. Epub 2021 Feb 18. PMID: 33599941.