Validity of Weighed Dietary Analysis in Teenage Emirate Males

Abstract

Recall of dietary history and weighed dietary analysis carried out by the subject have been shown to under estimate energy intake when validated against total energy expenditure measured by doubly labelled water (Rothenberg et al., 1998: Eur J Clin Nut, 52, 832-838). PURPOSE: To compare weighed dietary analysis, performed by the investigator, with energy expenditure measured by doubly labeled water in teenage Emirate males. METHODS: Thirty male students (age 16.5 ± 1.1 yrs, body mass 83.2 ± 20.1 kg, height 1.68 ± 0.05 m) from the Al Ain Military High school were monitored over 10 days. Total energy intake (EI) was measured using three-day weighed dietary analysis carried out by the investigator for each meal and both daily snacks. Furthermore, students were asked to report any additional food consumed. Energy expenditure (EE) was measured using the doubly labeled water method. RESULTS: Daily EE from the doubly labelled water was 3495 ± 446 kcal.d-1 (range 2434 - 4261 kcal.d-1) and estimated daily EI from the dietary analysis (n=27) was 2889 ± 702 kcal.d-1 (range 1599 - 4421 kcal). Breakfast, lunch and evening meal contributed 2206 ± 326 kcal.d-1 and the two snacks contributed the remaining 702 ± 123 kcal.d-1. There were no changes in the average body mass over the 10 day monitoring period (0.0 ± 0.8 kg). There was no relationship between energy deficit and body mass (r = 0.31, p=0.82) or age (r = 0.15, p=0.29). CONCLUSIONS: The EE and EI data may indicate that students were in energy deficit (568 ± 647 kcal.d-1) during the three-day dietary analysis period. However, maintenance of 10-day body mass suggests that the students were under-reporting or under-eating. Under-reporting was considered less likely as students were resident at the school for the entire study and all opportunities for obtaining food were monitored by the investigators. Weighed dietary analysis by the investigator may be the most accurate way to determine energy intake, although the results from this study suggest that changes to eating habits, whether conscious or not, can lead to a misrepresentation of dietary intake. This work was sponsored by the United Arab Emirates Armed Forces.