Determination of Total Energy Expenditure in 3- to 6-year-old Japanese Children Using the Double Labeled Water Method

The double labeled water (DLW, ²H₂¹⁸O) method for calculating the total production of CO₂ over several days is currently considered to be the most accurate for measurement of total energy expenditure (TEE), and the results obtained using it have been used for revision of energy requirements. So far, however, no data have been available for Japanese children. The objective of this study was to assess TEE in Japanese children using the DLW method. We used a cross-sectional population of 108 children (53 boys and 55 girls) aged 3 to 6 years. TEE was measured using the DLW method over 7 days under free-living conditions. The average body mass index (kg/m²) for boys and girls was 15.2±2.2 and 15.6±1.0 in those aged 3-4 years and 15.6±1.4 and 15.4±1.2 in those aged 5-6 years, respectively. The corresponding TEE (kcal/day) was 1220.9±329.0 and 1265.1±408.1, and 1669.9±520.1 and 1783.4±498.0, respectively, showing a significant age difference. However, when TEE was adjusted for fat-free mass, it showed no age or sex differences. We conclude that, in Japanese children, 1) TEE in those aged 3-4 years is similar to current Ministry of Health recommendations, whereas that in children aged 5-6 years is slightly excessive, and 2) the present results obtained from a large number of subjects will provide valuable reference data for Japanese children.