Question

Which of the following is the correct order with respect to the respiratory quotient of various substrates?

• A. Fats > Carbohydrates > Proteins
• B. Fats > Proteins > Carbohydrates
• C. Proteins > Fats > Carbohydrates
• D. Carbohydrates > Proteins > Fats

Answer 1

The correct option is D Carbohydrates > Proteins > Fats

Respiratory quotient (RQ) is the ratio of volume of carbon dioxide evolved to volume of oxygen consumed. The respiratory quotient varies for different respiratory substrates.

$\begin{array}{cc}\text{Respiratory Substrate}& \text{RQ value}\\ \text{Carbohydrate}& 1.0\\ \text{Fatty acid}& 0.7\\ \text{Protein}& 0.9\end{array}$

Hence, the correct order should be carbohydrates > proteins > fats.