When carbohydrates are insufficient due to fasting, how does the body finally extract energy from lipids and proteins?

1. During fasting, lipids and proteins are used for energy production. 2. Lipids are converted into fatty acids and proteins into amino acids. 3. These fatty acids and amino acids are converted into acetyl-CoA. 4. The acetyl-CoA is completely oxidized by the Krebs cycle in mitochondria to release energy. 5. The direct-to-glucose option is wrong because that pathway (gluconeogenesis) is a separate special case, not the energy route, so it is ruled out. 6. The glycogen option is wrong because that is storage of excess carbohydrate, not energy extraction, so it is ruled out. _Source: Balbharati (Maharashtra Board) Class 10 Science & Technology Part 2, Ch 2 "Life Processes in Living Organisms Part 1", p.23_