The basal metabolic rate (BMR) of Japanese females in their twenties (F2006) was compared with that of females of the same age measured in the 1950s (F1950; Nagamine and Suzuki, 1964). The subjects measured during 2004-2006 were 83 females (F2006) with no exercise habits. BMR was measured by using indirect calorimetry, and the body composition was assessed by dual-energy X-ray absorptiometry (DXA).
While the height and weight of F2006 were respectively significantly higher and heavier than those of F1950, BMR of F2006 (1, 110±112kcal/day) was not significantly different from that of F1950 (1, 132kcal/day). In addition, there was no difference in lean body mass (LBM) between the two groups. On the other hand, BMR per body weight of F2006 (21.5±2.1kcal/kg/day) was significantly lower than that of F1950 (23.1kcal/kg/day). BMR per body weight of F2006 was correlated with LBM per body weight (%LBM, r=0.51, p<0.001), although BMR per LBM of F2006 was not different from that of F1950.
These data suggest that BMR per body weight of the current young females of Japan is lower than that of the young females of the same age measured in the 1950s, during which data for establishing the BMR reference value in “Dietary Reference Intakes for Japanese, 2005” was obtained. Furthermore, the difference in BMR per body weight between the two groups can be explained by the difference in %LBM.
