title: Metabolic efficiency and energy expenditure during short-term overfeeding.
abstract: OBJECTIVE
  To investigate whether efficiency of weight gain during a short period of overfeeding is related to adaptive differences in basal metabolic rate (BMR) and physical activity.
  
  
  METHODS
  Fourteen healthy females (age 25+/-4 years, BMI 22.1+/-2.3 kg/m2).
  
  
  METHODS
  Subjects were overfed with a diet supplying 50% more energy than baseline energy requirements for 14 days. Overfeeding diets provided 7% of energy from protein, 40% from fat and 53% from carbohydrates. Body composition was determined using hydrodensitometry and isotope dilution, total energy expenditure (TEE) with doubly labeled water and basal metabolic rate (BMR) with indirect calorimetry. Physical activity (PA) was recorded with a tri-axial accelerometer.
  
  
  RESULTS
  Body weight increased by 1.45+/-0.86 kg (mean+/-S.D.) (P<0.0001), fat mass increased by 1.05+/-0.75 kg. Energy storage was 57.0+/-17.9 MJ, which is the difference between energy intake (207.2 MJ) and energy expenditure (150.2 MJ) during overfeeding. There was no difference between metabolically efficient and metabolically inefficient subjects in changes in BMR and PA.
  
  
  CONCLUSIONS
  These results indicate that the metabolic efficiency of weight gain was not related to adaptive changes in energy expenditure.
authors.affiliation: Department of Human Biology, Maastricht University, P.O. Box 616 6200 MD Maastricht, The Netherlands. A.Joosen@HB.Unimass.NL
authors.forename: Annemiek M C P
authors.initials: AM
authors.lastname: Joosen
authors.forename: Arjen H F
authors.initials: AH
authors.lastname: Bakker
authors.forename: Klaas R
authors.initials: KR
authors.lastname: Westerterp
mesh_terms: D000222:Adaptation, Physiological; D000273:Adipose Tissue / Q000033:anatomy & histology; D000328:Adult; D001481:Basal Metabolism; D001823:Body Composition; D001835:Body Weight; D002149:Energy Intake; D004734:Energy Metabolism; D005260:Female; D006801:Humans; D009068:Movement; D013997:Time Factors