Protein can redistribute from less trained muscles to more trained muscles if protein intake is insufficient.

“so if you see like say you spend a bunch of times on your bicep your biceps get really really big and you don't train your calf and your calf is actually unless just say your protein intake is insufficient you will start redistributing proteins from the calf up to the bicep to actually enable that growth and so you're thinking you're getting bigger but you're really just taking it from other places”