Eating protein after working out only affects the muscle's signaling pathways for about 4 hours - after that, the signaling goes back to normal even though muscle building continues.
Scientific Claim
The ingestion of protein after resistance exercise does not significantly affect muscle anabolic signaling pathways beyond the first 4 hours in healthy young men.
Source Excerpt
“We observed time-dependent changes in all the selected genes known to be upregulated following an exercise bout. In contrast, we did not observe any impact of protein feeding on muscle protein signaling or muscle gene expression (Figure 5). This is in line with previous work that suggests that the molecular response in skeletal muscle to protein ingestion is short lived (<4 h).”
Evidence from Studies
Supporting Studies
The anabolic response to protein ingestion during recovery from exercise has no upper limit in magnitude and duration in vivo in humans
The study measured muscle signaling proteins and gene expression related to anabolism and found no significant changes beyond the first 4 hours after protein ingestion, despite continued increases in muscle protein synthesis rates.