title: The Impact of Early Bedtimes on Adolescent Caloric Intake Varies by Chronotype.
abstract: OBJECTIVE
  Adolescent sleep restriction is common and can lead to overeating. Here, we test whether lengthening sleep via early bedtimes affects dietary intake differently for adolescents accustomed to a later sleep phase ("night owls") versus an earlier sleep phase ("morning larks").
  
  
  METHODS
  Using a randomized cross-over design, 67 adolescents changed bedtimes to create five-night periods of sleep restriction (6.5 hours in bed) versus healthy sleep (10 hours in bed). Caloric intake was measured via validated interviews. Phase preference was based on participants' premanipulation sleep.
  
  
  RESULTS
  Actigraphy verified that the manipulation altered sleep regardless of phase preference. Phase preference moderated the effect of the manipulation on cumulative caloric intake (p = .01-.03). Night owls showed little effect, but morning larks reduced their evening intake during healthy sleep.
  
  
  CONCLUSIONS
  An "early to bed" approach confers little dietary benefit for night owls but may have a protective effect for adolescents who gravitate toward earlier bedtimes.
authors.affiliation: Division of Behavioral Medicine and Clinical Psychology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; University of Cincinnati College of Medicine, Cincinnati, Ohio. Electronic address: dean.beebe@cchmc.org.
authors.forename: Dean W
authors.initials: DW
authors.lastname: Beebe
authors.affiliation: University of Cincinnati College of Medicine, Cincinnati, Ohio.
authors.forename: Amy
authors.initials: A
authors.lastname: Zhou
authors.affiliation: Division of Behavioral Medicine and Clinical Psychology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; University of Cincinnati College of Medicine, Cincinnati, Ohio.
authors.forename: Joseph
authors.initials: J
authors.lastname: Rausch
authors.affiliation: Boston College, Boston, Massachusetts.
authors.forename: Olivia
authors.initials: O
authors.lastname: Noe
authors.affiliation: Children's Hospital Colorado, University of Colorado School of Medicine, Aurora, Colorado.
authors.forename: Stacey L
authors.initials: SL
authors.lastname: Simon
mesh_terms: D056044:Actigraphy; D000293:Adolescent; D000294:Adolescent Behavior / Q000523:psychology*; D002909:Chronobiology Phenomena / Q000502:physiology*; D018592:Cross-Over Studies; D004032:Diet / Q000523:psychology*; D002149:Energy Intake; D005247:Feeding Behavior / Q000523:psychology*; D005260:Female; D006801:Humans; D007407:Interviews as Topic; D008297:Male; D012890:Sleep / Q000502:physiology*; D012892:Sleep Deprivation / Q000523:psychology*; D013997:Time Factors
keywords: Adolescence; Caloric intake; Circadian preference; Dietary changes; Experimental sleep restriction; Sleep