It's a function of diet and exercise. "Absorb" also begs the question "for what?" Your body can absorb protein and repurpose it into other proteins for muscles

It's a function of diet and exercise. "Absorb" also begs the question "for what?" Your body can absorb protein and repurpose it into other proteins for muscles or whatnot, but turning that protein into energy is harder. It's like saying that a city can absorb a terajoule of gasoline more easily than a terajoule of coal or a terajoule of lithium batteries. It's true, but "which is absorbed faster?" is a vast oversimplification of a more complicated question, which is "how much is needed?" To extend the analogy further, if a city had mostly electric cars and a coal power plant, it would have no trouble absorbing the lithium batteries or the coal, but would have more trouble absorbing the gasoline.