Can you build muscle and perform well as a vegetarian or vegan?
Yes — a vegan or vegetarian diet builds just as much muscle and strength as an omnivorous one when protein quantity and quality are matched, but a few specific nutrients (creatine, carnosine, B12, iron, DHA/EPA) don't show up in plants and need deliberate attention.
The old worry was that plant protein is inherently inferior for building muscle — lower in leucine, missing essential amino acids, poorly absorbed. That’s true of any single plant protein source in isolation, but nobody eats an isolated source. Combine legumes, grains, and soy (or use a blended/mycoprotein source) and you land on a full amino acid profile with leucine content that’s competitive with animal protein per gram, especially once you’re eating enough total protein to compensate for any per-meal shortfall.
The direct test backs this up. A 2023 randomized trial from Exeter had trained young adults eat either a high-protein vegan diet (built around mycoprotein) or an isonitrogenous omnivorous diet at roughly 1.8-2.0 g/kg/day protein through 10 weeks of high-volume resistance training. Muscle protein synthesis rates, fiber cross-sectional area, lean mass gain, and strength gains came out statistically the same between groups. A 2025 meta-analysis pooling 8 RCTs on plant-based versus omnivorous diets under resistance or high-intensity training found no meaningful difference in upper-body, lower-body, or overall strength. A separate 2023 meta-analysis of 10 studies went further, finding plant-based eating patterns were associated with a moderate aerobic-performance advantage and no strength/power cost. The pattern across this evidence is consistent: protein quantity and completeness — not its animal or plant origin — is what predicts the outcome.
Where the real gaps are
None of that makes a vegan diet nutritionally complete by default. Muscle creatine and carnosine stores run measurably lower in long-term vegetarians and vegans, since both come almost exclusively from meat and fish — closing that gap takes supplementation (creatine ~3-5 g/day, beta-alanine for carnosine), not more vegetables. B12 has zero reliable plant sources and roughly half of vegans test low without supplementing. Iron from plants is non-heme and absorbed less efficiently, raising deficiency risk, particularly in female athletes. DHA/EPA essentially don’t exist in plant foods (ALA converts poorly), so algae-oil supplementation is the practical fix.
The takeaway
Don’t let “is plant protein as good as animal protein” distract from the nutrients that actually separate vegan athletes from omnivores. Build sufficient total protein, then treat creatine, B12, iron, and algae-based omega-3s as non-negotiable line items, not afterthoughts.