Why
is the RQ value sometimes difficult to interpret?
Unfortunately, R values that are not close to 1.0 or 0.7 are oftendifficult to interpret. For example, if an animal has an R value of 0.8,a researcher cannot simply conclude that its cells are catabolizingproteins, because the catabolism of a mixture of carbohydrates andlipids (or of all three foodstuffs) could also produce an R value of0.8. The potential for ambiguity stems from the fact that althoughthree unknowns exist (the proportions of the three foodstuffs beingoxidized), the R or RQ value encompasses only two knowns (O2consumption and CO2 production). The ambiguity can be resolved,but only by measuring additional indices of cellular function besidesO2 consumption and CO2 production.