The relationship between food intake and respiratory quotient in mice.

It is a generally accepted principle that the respiratory quotient is influenced by the composition of the food eaten, but the effect on it of the quantity of food seems to have been neglected. Occasional papers can be found which contain data showing an increase in R.Q. at higher intakes (e.g. Williams, Riche & LuSk, 1912; Forbes, Swift, Elliott & James, 1946)) but the levels used are too few to just@ quantitative inferences. One reason for this omission is undoubtedly that the field has been dominated by the important conception of ‘basal metabolism’, so that most studies have been carried out on animals in the post-absorptive state, and periods of observation have tended to be short. The evidence for a quantitative relationship between R.Q. and food intake which is presented in this paper is derived from observations made over 24 hr. periods on animals provided with food and drink.