During prolonged fasting

Options

A. The first to be used up are carbohydrates, next fat is withdrawn and proteins are metabolized at the last
B. The first to be used up are the fats, next carbohydrates are withdrawn from stored glycogen in the liver and muscles and proteins are withdrawn at the last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

A

Explanation

The first fuel that our body breaks down for energy is carbohydrates. Since they are easily accessible and turned into energy.
When glucose and glycogen are not available then our body breaks down fatty compounds known as triglycerol which are present in adipose or fat tissue. Because fat is a high energy source with nine calories per gram.
At the end protein break down and metabolise into urea in liver.