After a meal rich in amino acids, what happens to protein metabolism?

• A. Protein breakdown decreases and synthesis increases somewhat
• B. Protein breakdown increases
• C. Protein synthesis stops
• D. No change occurs

Answer: (A)

After a meal rich in amino acids, the body shifts into an anabolic, fed state where building new proteins is favored. The sudden rise in amino acids stimulates protein synthesis in tissues like skeletal muscle, providing the substrates and signaling that drive translation and growth. At the same time, insulin released in response to the meal further promotes synthesis and also suppresses proteolysis, reducing the breakdown of existing proteins. Because synthesis is increased and breakdown is decreased, the net protein balance moves toward gain, though the rise in synthesis is not infinite—it’s a partial, positive shift. This is why the correct view is that protein breakdown decreases and synthesis increases somewhat.