Question

During prolonged fasting

• A. The first to be used up are carbohydrates, next fat is withdrawn and proteins are metabolised at the last
• B. The first to be used up are the fats, next carbohydrates are withdrawn from stored glycogen in the liver and muscles and proteins are withdrawn at the last
• C. First lipids are used up, then proteins and finally carbohydrate
• D. None of these

Answer 1

The correct option is A The first to be used up are carbohydrates, next fat is withdrawn and proteins are metabolised at the last

The calorific value of carbohydrate is 4,protein is 4 and fat is 9.During prolonged fasting, first carbohydrates are used up then fats and proteins are used at the last. Carbohydrate and fat metabolism can easily produce energy 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.

So,the correct option is 'A'.