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.