Validation of a pre-coded food diary with energy expenditure, comparison of under-reporters v. acceptable reporters

The objective of the present study was to compare energy intake (EI) assessed from a pre-coded food diary (PFD) with energy expenditure (EE) measured by a validated position-and-movement monitor (ActiReg®; PreMed AS, Oslo, Norway) in a group of Norwegian 9-year-olds. Moreover, we examined whether and how under-reporters (UR), identified with ActiReg®, differed from acceptable reporters (AR) according to food intake and BMI. A total of fifty-one 9-year-olds completed PFD and ActiReg®. The present study showed that on average EI was underestimated by 18 % compared with EE measured by ActiReg®. The 95 % confidence limits of agreement in a Bland–Altman plot for EI and EE varied from 1·97 MJ to −4·23 MJ (sd 2) among the girls and from 0·74 MJ to −5·26 MJ (sd 2) among the boys. The Pearson correlation coefficient between EI and EE was 0·28 (P=0·05) for males and females combined. Fifty-seven per cent of the participants were classified as AR, 39 % as UR and 4 % as over-reporters with the PFD. Under-reporting of energy remains a problem with the PFD method used in a group of 9-year-olds, especially among boys. However, UR and AR did not show a systematic misreporting related to macronutrients, unhealthy foods or BMI.