Which energy source becomes primary when carbohydrate stores are low, according to the source?

Which energy source becomes primary when carbohydrate stores are low, according to the source?

• A. Fats
• B. Amino Acids
• C. Proteins
• D. Water

Answer: (B)

When carbohydrate stores run low, the body shifts to fats as the primary fuel source. Fatty acids released from fat tissue are oxidized by muscles to produce ATP, and the liver can convert some of these fatty acids into ketone bodies to help power the brain and other tissues during extended low-carb periods. Amino acids, while they can be used for glucose production through gluconeogenesis or for energy if needed, are not the main energy source in this situation; relying on them would lead to loss of lean tissue. Water does not provide energy.

When carbohydrate stores run low, the body shifts to fats as the primary fuel source. Fatty acids released from fat tissue are oxidized by muscles to produce ATP, and the liver can convert some of these fatty acids into ketone bodies to help power the brain and other tissues during extended low-carb periods. Amino acids, while they can be used for glucose production through gluconeogenesis or for energy if needed, are not the main energy source in this situation; relying on them would lead to loss of lean tissue. Water does not provide energy.