title: Validation of a pre-coded food diary used among 13-year-olds: comparison of energy intake with energy expenditure.
abstract: OBJECTIVE
  To validate energy intake (EI) estimated from pre-coded food diaries against energy expenditure (EE) measured with a validated position-and-movement monitor (ActiReg) in groups of 13-year-old Norwegian schoolchildren.
  
  
  METHODS
  Two studies were conducted. In study 1 the monitoring period was 4 days; participants recorded their food intake for four consecutive weekdays using food diaries and wore the ActiReg during the same period. In study 2 the monitoring period was 7 days; participants recorded their food intake for four consecutive days but wore the ActiReg for a whole week.
  
  
  METHODS
  Participants were recruited from grade 8 in a school in and one outside Oslo (Norway).
  
  
  METHODS
  Forty-one and 31 participants from study 1 and 2, respectively, completed the study.
  
  
  RESULTS
  The group average EI was 34% lower than the measured EE in study 1 and 24% lower in study 2. The width of the 95% confidence limits of agreement in a Bland-Altman plot for EI and EE varied from -0.2 MJ to 8.2 MJ in study 1 and from -2.3 MJ to 6.9 MJ in study 2. The Pearson correlation coefficients between reported energy intake and expenditure were 0.47 (P=0.002) in study 1 and 0.74 (P<0.001) in study 2.
  
  
  CONCLUSIONS
  The data showed that there was substantial variability in the accuracy of the food diary at the individual level. Furthermore, the diary underestimated the average energy intake. The ability of the food diary to rank individuals according to energy intake was found to be good in one of the studies and moderate in the other.
authors.affiliation: Department of Nutrition, University of Oslo, POB 1046 Blindern, Norway. l.f.andersen@medisin.uio.no
authors.forename: Lene F
authors.initials: LF
authors.lastname: Andersen
authors.forename: Magnhild L
authors.initials: ML
authors.lastname: Pollestad
authors.forename: David R
authors.initials: DR
authors.lastname: Jacobs
authors.forename: Arne
authors.initials: A
authors.lastname: Løvø
authors.forename: Bo-Egil
authors.initials: BE
authors.lastname: Hustvedt
mesh_terms: D000293:Adolescent; D001481:Basal Metabolism / Q000502:physiology; D015930:Diet Records; D004034:Diet Surveys; D002149:Energy Intake / Q000502:physiology*; D004734:Energy Metabolism / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009664:Norway; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012737:Sex Factors