Glossary · Definition
Muscle protein synthesis
Muscle protein synthesis (MPS) is the process by which muscle tissue is built from amino acids. Triggered most strongly by resistance training + a meal containing 25-40g of high-quality protein within 2 hours.
Definition
Muscle protein synthesis (MPS) is the process by which muscle tissue is built from amino acids. Triggered most strongly by resistance training + a meal containing 25-40g of high-quality protein within 2 hours.
What it means
MPS is regulated by mTOR signaling, which responds primarily to leucine concentration. The 'leucine threshold' for stimulating MPS is roughly 2.5-3g per meal — achieved by 25-40g of complete protein (whey, eggs, meat, fish, dairy, soy). Multiple meals/day beat one big protein bolus. The post-workout 'anabolic window' is real but wider than originally thought (2-4 hours).
Advertisement
Why it matters
Spreading protein across 3-4 meals optimizes daily MPS more than concentrating it. People who eat all their protein at dinner don't get the same muscle-building stimulus as people who hit 25-40g at each meal. This is the actual reason for protein-distribution recommendations — not a vague 'metabolism' story.
Related free tools
Frequently asked questions
How much protein per meal?
25-40g of complete protein for most adults; 40-50g for those over 60 (anabolic resistance increases with age).
Plant proteins enough?
Yes if you combine sources (rice + beans, soy + grains) to get a complete amino-acid profile, or use a single complete plant source like soy, quinoa, or buckwheat.