title: Effects of inactivity and diet composition on human energy balance.
abstract: OBJECTIVE
  To investigate the influences of inactivity and dietary macronutrient composition on energy and fat balance and to look for interactions between them.
  
  
  METHODS
  Two-day measurements of energy expenditure and substrate oxidation on five occasions; ad libitum food intake from diets of 35% and 60% energy as fat, with and without imposed activity, and a fixed overfeeding at 35% fat with free activity.
  
  
  METHODS
  Eight normal-weight male volunteers.
  
  
  METHODS
  Energy expenditure and substrate oxidation by indirect whole-body calorimetry, and macronutrient intakes from food consumption on ad libitum regimens.
  
  
  RESULTS
  Subjects consumed the same energy, mean 11.6 MJ/d, regardless of activity level, on the 35% diet. Subjects consumed more energy on the 60% than the 35% diet, mean 14 vs. 11.6 MJ/d. Inactivity induced a strong positive energy balance: 5.1 (60% diet), and 2.6 MJ/d (35% diet). Energy balance with activity was not significantly different between diets, nor significantly different from zero: 1.1 MJ/d (60% diet), and -0.2 MJ/d (35% diet). When intentionally overfed, subjects failed to compensate by raising voluntary activity.
  
  
  CONCLUSIONS
  Energy intake was not regulated over a 2-day period in response to either imposition of inactivity or a high-fat diet. Activity proved essential to the avoidance of significant positive energy balance.
authors.affiliation: MRC Dunn Clinical Nutrition Centre, Cambridge, UK. Peter.Murgatroyd@mrc-dunn.cam.ac.uk
authors.forename: P R
authors.initials: PR
authors.lastname: Murgatroyd
authors.forename: G R
authors.initials: GR
authors.lastname: Goldberg
authors.forename: F E
authors.initials: FE
authors.lastname: Leahy
authors.forename: M B
authors.initials: MB
authors.lastname: Gilsenan
authors.forename: A M
authors.initials: AM
authors.lastname: Prentice
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D002151:Calorimetry; D004032:Diet; D004040:Dietary Carbohydrates / Q000378:metabolism*; D004041:Dietary Fats / Q000378:metabolism*; D002149:Energy Intake; D004734:Energy Metabolism; D015444:Exercise; D006801:Humans; D008297:Male
chemical_list: D004040:Dietary Carbohydrates; D004041:Dietary Fats