title: Observations in energy and macronutrient intake during prolonged bed-rest in a head-down tilt position.
abstract: OBJECTIVE
  to report observations in energy and macronutrient intakes, and body weight during prolonged bed-rest in a head down tilt (HDT) position.
  
  
  METHODS
  open study, each subject was his own control, and was studied during 14 days of baseline, 42 days of -6 degrees HDT bed-rest, and 12 days of recovery.
  
  
  METHODS
  eight healthy young man were recruited, one dropped out.
  
  
  METHODS
  energy and macronutrient content of the diet were calculated from weighed amounts of food consumed and French food composition tables.
  
  
  RESULTS
  body weight declined during HDT (74.0+/-3.2 to 71.8+/-3.2 kg, P<< 0.001) and increased during recovery (72.7+/-3.2 kg, P<< 0. 001). Energy intake decreased during HDT (by 17% after 4-5 weeks) and increased during recovery but remained lower than during baseline (P<< 0.001). During HDT fat intake, expressed by a percentage of energy, decreased (P<< 0.01) while carbohydrate increased (P= 0.04); protein intake did not change (P= 0.08). The reverse trends were observed during recovery.
  
  
  CONCLUSIONS
  the present study reports a spontaneous reduction in energy and relative fat intake during prolonged HDT bed rest. We believe that these findings have implications for the clinical setting.
authors.affiliation: Centre de Recherche en Nutrition Humaine, Clermont-Ferrand Cedex 1, 63009, France.
authors.forename: P
authors.initials: P
authors.lastname: Ritz
authors.forename: A
authors.initials: A
authors.lastname: Maillet
authors.forename: S
authors.initials: S
authors.lastname: Blanc
authors.forename: R J
authors.initials: RJ
authors.lastname: Stubbs
mesh_terms: D000328:Adult; D001066:Appetite; D001510:Bed Rest; D001835:Body Weight; D004040:Dietary Carbohydrates / Q000008:administration & dosage / Q000378:metabolism*; D004041:Dietary Fats / Q000008:administration & dosage / Q000378:metabolism*; D004044:Dietary Proteins / Q000008:administration & dosage / Q000378:metabolism*; D002149:Energy Intake; D006801:Humans; D008297:Male; D009747:Nutritional Physiological Phenomena; D011187:Posture
chemical_list: D004040:Dietary Carbohydrates; D004041:Dietary Fats; D004044:Dietary Proteins