Question

Define RQ. What is the RQ value for fats?

Answer 1

Convenient utilization of RQ i.e. respiratory quotient can be seen in extreme cases of obstructive lungs disease where one has to spend more and more metabolic energy on respiratory functions. By making more use of fats in food the RQ value can be driven down, decreasing the amount of carbon-dioxide produced.

Complete answer:
Respiratory quotient (RQ) also called as the respiratory ratio; it is defined as the volume of carbon dioxide released over the volume of oxygen absorbed during respiration. It is a unit less number that is used when the basal metabolic rate is calculated in the estimation from carbon dioxide production to oxygen absorption. The value of Respiratory Quotient shows that metabolism of which macronutrients (among fats, carbohydrates and proteins) takes place by the different energy pathways for metabolism. If metabolism is mainly for fats or lipids, the RQ- Respiratory Quotient value is 0.7, for proteins the value comes 0.8, and for carbohydrates value is 1.0.
RQ values for fat, protein, and carbohydrate are 0.7, 0.8, and 1.0, respectively. Therefore, an RQ of less than 1.0 generally shows a bit much carbohydrate or calorie calculations that show increased carbon-dioxide production and cause difficulty in breathing ventilation.

Note: Among the macromolecules, the molecules that are longer oxidized (for example glucose) require less oxygen to get fully metabolized and, thus, they always have higher RQ- respiratory quotients.
Vice-versa, the molecules that are less oxidized (for example, fatty acids) need larger amounts of oxygen to metabolize and show lower respiratory quotients.