Is it harder to build muscle on a vegan diet?

The objection

“Plant protein is lower quality, less leucine, less complete. You can’t build serious muscle without meat, eggs and whey.”

The answer

There’s a real mechanism here, so let’s grant the kernel of truth before dismantling the conclusion.

Plant proteins are typically a little lower in leucine, the amino acid that flips on muscle-protein synthesis, and slightly less digestible. So gram-for-gram, an isolated plant protein can trigger a marginally smaller anabolic response than whey. The objection has a real basis.

The gap is small and almost entirely closable, which is exactly what the controlled trials show. A 2024 meta-analysis of randomised trials found no significant difference between plant and animal protein for muscle strength or physical performance, and only a small edge for animal protein on muscle mass, an edge that vanished for soy, which matched milk protein. The shortfall, where it exists, is against rice and oat proteins, not against a varied plant diet built on soy, beans and grains.

The fix is dull and effective. Eat a bit more total protein, nudging towards the higher end athletes already target, and lean on higher-leucine sources like soy, lentils and seitan. Spread it across meals.

There’s a bonus the objection never sees coming. Vegetarians and vegans start with lower muscle creatine, so they respond more strongly to creatine supplementation, a cheap, well-evidenced legal aid to strength and power. The lower starting point turns into an advantage.

Building serious muscle on plants is straightforwardly achievable. It asks for slightly more attention to total protein, not for meat.