Validation of self-reported energy intake by a self-administered diet history questionnaire using the doubly labeled water method in 140 Japanese adults.

OBJECTIVE: To validate reported energy intake (rEI) with a self-administered diet history questionnaire (DHQ) against total energy expenditure (TEE) by the doubly labeled water (DLW) method. SUBJECTS: A total of 140 healthy Japanese adults (67 men and 73 women) aged 20-59 years living in four areas in Japan. METHODS: Energy intake was assessed twice with DHQ over a 1-month period before and after TEE measurement (rEI(DHQ1) and rEI(DHQ2), respectively). TEE was measured by DLW during 2 weeks (TEE(DLW)). RESULTS: Mean rEI(DHQ1) was lower than those of TEE(DLW) by 1.9+/-2.4 MJ/day (16.4%, P<0.001) for men and 0.6+/-1.9 MJ/day (6.0%, P<0.01) for women. In men and women together, 62 subjects (44%) were defined as underreporters (rEI(DHQ1)/TEE(DLW) <0.84), 58 (41%) as acceptable reporters (0.84-1.16) and 20 (14%) as over-reporters (>1.16). Pearson correlation coefficient was 0.34 for men and 0.22 for women. After adjustment for the dietary and non-dietary factors related to rEI(DHQ1)/TEE(DLW), the correlation coefficient improved to 0.42 and 0.37, respectively. CONCLUSION: The energy intake assessed with DHQ correlated low to modestly with TEE measured by DLW. In addition, DHQ underestimated energy intake at a group level. Caution is needed when energy intake was evaluated by DHQ at both individual and group levels.

Physical activity level in healthy free-living Japanese estimated by doubly labelled water method and International Physical Activity Questionnaire.

OBJECTIVE: To measure total energy expenditure (TEE) for normal healthy Japanese by the doubly labelled water (DLW), and to compare the physical activity level (PAL) among categories classified by the categories used in daily reference intake (DRI), Japan and the International Physical Activity Questionnaire (IPAQ). SUBJECTS AND METHODS: A total of 150 healthy Japanese men and women aged 20- to 59-year-old living in four districts of Japan. TEE was measured by the DLW method, and the PAL was calculated from TEE divided by basal metabolic rate. Simultaneously with TEE measurement, the PAL was assessed employing the categories used in DRI, Japan and IPAQ. RESULTS: The average TEE and PAL were 10.78+/-1.67 MJ/day and 1.72+/-0.22 for males and 8.37+/-1.30 MJ/day and 1.72+/-0.27 for females, respectively. The subjects in the highly active categories assessed by both DRI and IPAQ showed significantly higher PAL compared with less active categories. However, PALs among light and moderate categories by DRI, and insufficient and sufficiently active by IPAQ were not significantly different. CONCLUSIONS: In developed countries, highly active subjects could be assessed by a simple questionnaire. However, the questionnaire should be improved to clarify the sedentary to moderately active subjects by assessing carefully very light to moderate physical activity.