What is the approximate RER for protein utilization?

The resting energy expenditure (RER) for protein utilization is approximately 0.8. The RER, or respiratory exchange ratio, is used to assess the ratio of carbon dioxide produced to oxygen consumed, which can indicate which macronutrients (carbohydrates, fats, or proteins) are being used for energy.

When protein is primarily utilized for energy, the RER value reflects this metabolic process, hovering around 0.8. This number suggests that while a mix of macronutrients might be utilized, protein metabolism specifically results in a unique balance of oxygen consumption and carbon dioxide production. This value is important for understanding how the body is sourcing energy, particularly in different states of nutrition and exercise.

In contrast, values such as 0.6 are generally associated with fat oxidation, while values approaching 1.0 indicate carbohydrate utilization. Thus, the selection of 0.8 accurately represents the RER during protein metabolism in the context of energy utilization.