When carbohydrates are unavailable to prime the metabolic pump intermediate products of fat metabolism such as what?

When carbohydrates are unavailable, the body relies on fat metabolism for energy, leading to the production of ketone bodies such as acetoacetate, beta-hydroxybutyrate, and acetone. These ketones serve as alternative fuel sources, especially for the brain and muscles, during prolonged fasting or low-carbohydrate conditions. Additionally, fatty acids are oxidized to produce acetyl-CoA, which can enter the citric acid cycle for energy production. This shift helps maintain energy levels when glucose is scarce.