Self-reported dietary energy intake of normal weight, overweight and obese adolescents.

OBJECTIVE

The purpose of the present paper was to assess dietary energy reporting as a function of sex and weight status among Ontario and Alberta adolescents, using the ratio of energy intake (EI) to estimated BMR (BMRest).

DESIGN

Data were collected using the FBQ, a validated web-based dietary assessment tool (including a 24 h dietary recall, FFQ, and food and physical activity behavioural questions). BMI was calculated from self-reported height and weight and participants were classified as normal weight, overweight or obese. BMR was calculated using the WHO equations (based on weight). Reporting status was identified using the ratio EI:BMRest.

SETTING

Data were collected in public, Catholic and private schools in Ontario and Alberta, Canada.

SUBJECTS

A total of 1917 (n 876 male and n 1041 female) students (n 934 grade 9 and n 984 grade 10) participated.

RESULTS

The mean EI:BMRest ratio across all participants was 1.4 (sd 0.6), providing evidence of under-reporting for the total sample. Females under-reported more than males (t = 6.27, P < 0.001), and under-reporting increased with increasing weight status for both males (F = 33.21, P < 0.001) and females (F = 14.28, P < 0.001). After removing those who reported eating less to lose weight, the EI:BMRest was 1.56 (sd 0.6) for males and 1.4 (sd 0.6) for females.

CONCLUSION

The present study highlights methodological challenges associated with self-reported dietary data. Systematic differences in under-reporting of dietary intake by gender and weight status were observed using a web-based survey, similar to observations made using paper-based 24 h recalls and dietitian interviews.