When carbohydrate intake is insufficient, the liver produces what as an alternative energy source?

When carbohydrate intake is insufficient, the liver produces what as an alternative energy source?

• A. Ketones
• B. Glucose
• C. Glycogen
• D. Insulin

Answer: (A)

When carbohydrate intake is low, the body shifts to using fat for fuel and the liver makes ketone bodies to supply energy. Free fatty acids released from fat tissue are converted in the liver into acetyl-CoA, and because there isn’t enough oxaloacetate to make glucose for immediate energy, acetyl-CoA is diverted into ketone production. The resulting ketone bodies travel through the bloodstream to tissues (including the brain) and serve as an alternative energy source when glucose is scarce. Glycogen stores are depleted after fasting and provide a temporary glucose source, glucose is produced mainly through gluconeogenesis rather than directly as a liver energy source in this context, and insulin is a hormone, not an energy source.

When carbohydrate intake is low, the body shifts to using fat for fuel and the liver makes ketone bodies to supply energy. Free fatty acids released from fat tissue are converted in the liver into acetyl-CoA, and because there isn’t enough oxaloacetate to make glucose for immediate energy, acetyl-CoA is diverted into ketone production. The resulting ketone bodies travel through the bloodstream to tissues (including the brain) and serve as an alternative energy source when glucose is scarce. Glycogen stores are depleted after fasting and provide a temporary glucose source, glucose is produced mainly through gluconeogenesis rather than directly as a liver energy source in this context, and insulin is a hormone, not an energy source.