title: Sleep curtailment is accompanied by increased intake of calories from snacks.
abstract: BACKGROUND
  Short sleep is associated with obesity and may alter the endocrine regulation of hunger and appetite.
  
  
  OBJECTIVE
  We tested the hypothesis that the curtailment of human sleep could promote excessive energy intake.
  
  
  METHODS
  Eleven healthy volunteers [5 women, 6 men; mean +/- SD age: 39 +/- 5 y; mean +/- SD body mass index (in kg/m(2)): 26.5 +/- 1.5] completed in random order two 14-d stays in a sleep laboratory with ad libitum access to palatable food and 5.5-h or 8.5-h bedtimes. The primary endpoints were calories from meals and snacks consumed during each bedtime condition. Additional measures included total energy expenditure and 24-h profiles of serum leptin and ghrelin.
  
  
  RESULTS
  Sleep was reduced by 122 +/- 25 min per night during the 5.5-h bedtime condition. Although meal intake remained similar (P = 0.51), sleep restriction was accompanied by increased consumption of calories from snacks (1087 +/- 541 compared with 866 +/- 365 kcal/d; P = 0.026), with higher carbohydrate content (65% compared with 61%; P = 0.04), particularly during the period from 1900 to 0700. These changes were not associated with a significant increase in energy expenditure (2526 +/- 537 and 2390 +/- 369 kcal/d during the 5.5-h and 8.5-h bedtime periods, respectively; P = 0.58), and we found no significant differences in serum leptin and ghrelin between the 2 sleep conditions.
  
  
  CONCLUSIONS
  Recurrent bedtime restriction can modify the amount, composition, and distribution of human food intake, and sleeping short hours in an obesity-promoting environment may facilitate the excessive consumption of energy from snacks but not meals.
authors.affiliation: Department of Medicine, The University of Chicago, Chicago, IL 60637, USA.
authors.forename: Arlet V
authors.initials: AV
authors.lastname: Nedeltcheva
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Kilkus
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Imperial
authors.forename: Kristen
authors.initials: K
authors.lastname: Kasza
authors.forename: Dale A
authors.initials: DA
authors.lastname: Schoeller
authors.forename: Plamen D
authors.initials: PD
authors.lastname: Penev
mesh_terms: D000328:Adult; D001066:Appetite / Q000502:physiology; D001823:Body Composition / Q000502:physiology; D001835:Body Weight / Q000502:physiology; D018592:Cross-Over Studies; D004435:Eating / Q000502:physiology; D002149:Energy Intake / Q000502:physiology*; D004734:Energy Metabolism / Q000502:physiology; D005260:Female; D054439:Ghrelin / Q000097:blood*; D006801:Humans; D020738:Leptin / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood / Q000209:etiology*; D012892:Sleep Deprivation / Q000097:blood* / Q000503:physiopathology*
chemical_list: D054439:Ghrelin; D020738:Leptin