Question

During prolonged fasting, in what sequence are the following organic compounds used up by the body?

• A. first carbohydrates, next fats and lastly proteins
• B. first fats, next carbohydrates and lastly proteins
• C. first carbohydrates, next proteins and lastly lipids
• D. first proteins, next lipids and lastly carbohydrates

Answer 1

The correct option is A first carbohydrates, next fats and lastly proteins

During prolonged fasting, first carbohydrates are used up then fats and proteins are used last. Carbohydrate and fat metabolism can produce energy more easily than protein and they follow a more or less simpler pathway to enter into TCA cycle. When all carbohydrates of the body are used up then fats are converted into carbohydrates and when all fats are used up then ultimately proteins of the body are converted into carbohydrates to be used up by the body.