What is the purpose of ketone metabolism in starvation?

• A. The adaptation to starvation with a ketone-based fuel system minimizes gluconeogenesis and further protein breakdown
• B. It increases glucose production
• C. It inhibits ketone production
• D. It promotes amino acid synthesis

Answer: (A)

During starvation the body shifts to using ketone bodies as a major fuel source, especially for the brain. This ketone-based fuel system reduces the brain’s need for glucose, which in turn lowers the amount of gluconeogenesis required to supply glucose. With less glucose demand from hepatic glucose production, fewer amino acids from muscle are mobilized to serve as substrates for gluconeogenesis, helping to preserve lean body protein. So the primary purpose of ketone metabolism in starvation is to provide an alternative energy source that minimizes both gluconeogenesis and further protein breakdown.

In other words, this adaptation prioritizes ketones over continuous glucose production, reducing muscle proteolysis. The other ideas—increasing glucose production, inhibiting ketone production, or promoting amino acid synthesis—don’t align with the physiological shift that occurs during starvation, where ketones supply energy and spare proteins rather than boosting glucose or building proteins.