Respiratory Quotient

The Respiratory Quotient (RQ) tells us what type of fuel your body is primarily burning — carbohydrates or fats. An RQ closer to 1.0 means you are burning more carbohydrates, while a lower value near 0.7 indicates your body is using stored fat for energy.

Respiratory Quotient is the ratio of carbon dioxide produced (VCO₂) to oxygen consumed (VO₂) during metabolism. Carbohydrate oxidation yields RQ ≈ 1.0, protein ≈ 0.82, and fat ≈ 0.70. Indirect calorimetry uses RQ measurement to determine substrate utilisation patterns and total energy expenditure.

Understanding your body fuel preference helps tailor your diet and exercise plan. An RQ trending toward fat oxidation indicates your weight management strategy is effectively targeting stored fat — a key metric Dr. Joseph Wang monitors when optimising your weight loss programme.