title: Elevated objectively measured but not self-reported energy intake predicts future weight gain in adolescents.
abstract: BACKGROUND
  Although obesity putatively occurs when individuals consume more calories than needed for metabolic needs, numerous risk factor studies have not observed significant positive relations between reported caloric intake and future weight gain, potentially because reported caloric intake is inaccurate.
  
  
  OBJECTIVE
  The present study tested the hypothesis that objectively measured habitual energy intake, estimated with doubly labeled water, would show a stronger positive relation to future weight gain than self-reported caloric intake based on a widely used food frequency measure.
  
  
  METHODS
  Two hundred and fifty-three adolescents completed a doubly labeled water (DLW) assessment of energy intake (EI), a food frequency measure, and a resting metabolic rate (RMR) assessment at baseline, and had their body mass index (BMI) measured at baseline and at 1- and 2-year follow-ups.
  
  
  RESULTS
  Controlling for baseline RMR, elevated objectively measured EI, but not self-reported habitual caloric intake, predicted increases in BMI over a 2-year follow-up. On average, participants under-reported caloric intake by 35%.
  
  
  CONCLUSIONS
  RESULTS provide support for the thesis that self-reported caloric intake has not predicted future weight gain because it is less accurate than objectively measured habitual caloric intake, suggesting that food frequency measures can lead to misleading findings. However, even objectively measured caloric intake showed only a moderate relation to future weight gain, implying that habitual caloric intake fluctuates over time and that it may be necessary to conduct serial assessments of habitual intake to better reflect the time-varying effects of caloric intake on weight gain.
authors.affiliation: Oregon Research Institute, Eugene, OR, USA. Electronic address: estice@ori.org.
authors.forename: Eric
authors.initials: E
authors.lastname: Stice
authors.affiliation: Oregon Research Institute, Eugene, OR, USA.
authors.forename: Shelley
authors.initials: S
authors.lastname: Durant
mesh_terms: D000293:Adolescent; D001481:Basal Metabolism; D015992:Body Mass Index; D001835:Body Weight; D002149:Energy Intake; D005260:Female; D005500:Follow-Up Studies; D005544:Forecasting; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D009765:Obesity / Q000517:prevention & control; D064887:Observational Studies as Topic; D016032:Randomized Controlled Trials as Topic; D057566:Self Report; D015430:Weight Gain; D055815:Young Adult
keywords: Caloric intake; Doubly labeled water; Prospective; Weight gain