The post-absorptive resting metabolic rate was reassessed by using published data for the Japanese basal metabolic rate (BMR). Concurrence between the observed value and that predicted by widely used equations for calculating BMR were also examined. All of the BMR data were measured under the post-absorptive condition early in the morning. The BMR value for each subject was also predicted from the sex, age and weight by using the equations presented by the Japanese Recommended Dietary Allowance (RDA-Jpn) (1999), Schofield (1985) and FAO/WHO/UNU (1985). A stepwise regression analysis of the original data indicated that weight alone explained more than 40% of the BMR variance, while other independent variables (sex, age, height, BMI, and indoor and outdoor temperature) together explained 77.9% of the BMR variance. The difference between the observed value and that predicted by the RDA-Jpn equation was higher for lean subjects over 18 years of age who had been classified according to the body mass index (BMI) (BMI≤18.4kg/m2), than those predicted by the other equations. In contrast, the difference was less for the normal-weight subjects (18.5kg/m2≤BMI≤24.9kg/m2). The degree of concurrence between the observed and predicted value thus differed by group based on a subject's BMI. This finding indicates that the body composition should be examined in a future study to provide a more appropriate database for BMR than that based on previous BMR measurements.
