Muscle protein synthesis (MPS) is the process by which the body builds new muscle protein, primarily triggered by resistance exercise and adequate protein intake — especially leucine-rich protein. It's the mechanism behind why pairing strength training with enough protein helps preserve or build lean mass during GLP-1 treatment, rather than relying on either alone.
After a protein-containing meal the rate of MPS climbs, peaks, and then plateaus — it's near-maximally stimulated at roughly 0.4 g/kg of body weight per meal, and eating far more in one sitting adds proportionally less to it. That saturating rate — not a limit on how much protein the body can absorb — is the real finding behind the "30g of protein per meal" myth. What reliably drives MPS is hitting your daily protein total and training your muscles: see strength training and protein, fat, and carbohydrates.