title: Effect of diet composition on energy expenditure during weight loss: the POUNDS LOST Study.
abstract: BACKGROUND
  Weight loss reduces energy expenditure, but the contribution of different macronutrients to this change is unclear.
  
  
  OBJECTIVE
  We tested the hypothesis that macronutrient composition of the diet might affect the partitioning of energy expenditure during weight loss.
  
  
  METHODS
  A substudy of 99 participants from the Preventing Overweight Using Novel Dietary Strategies (POUNDS LOST) trial had total energy expenditure (TEE) measured by doubly labeled water, and resting energy expenditure (REE) measured by indirect calorimetry at baseline and repeated at 6 months in 89 participants. Participants were randomly assigned to one of four diets with either 15 or 25% protein and 20 or 40% fat.
  
  
  RESULTS
  TEE and REE were positively correlated with each other and with fat-free mass and body fat, at baseline and 6 months. The average weight loss of 8.1 ± 0.65 kg (least-square mean ± s.e.) reduced TEE by 120 ± 56  kcal per day and REE by 136 ± 18 kcal per day. A greater weight loss at 6 months was associated with a greater decrease in TEE and REE. Participants eating the high-fat diet (HF) lost significantly more fat-free mass (1.52 ± 0.55 kg) than the low-fat (LF) diet group (P<0.05). Participants eating the LF diet had significantly higher measures of physical activity than the HF group.
  
  
  CONCLUSIONS
  A greater weight loss was associated with a larger decrease in both TEE and REE. The LF diet was associated with significant changes in fat-free body mass and energy expenditure from physical activity compared with the HF diet.
authors.affiliation: Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA. brayga@pbrc.edu
authors.forename: G A
authors.initials: GA
authors.lastname: Bray
authors.forename: S R
authors.initials: SR
authors.lastname: Smith
authors.forename: L
authors.initials: L
authors.lastname: DeJonge
authors.forename: R
authors.initials: R
authors.lastname: de Souza
authors.forename: J
authors.initials: J
authors.lastname: Rood
authors.forename: C M
authors.initials: CM
authors.lastname: Champagne
authors.forename: N
authors.initials: N
authors.lastname: Laranjo
authors.forename: V
authors.initials: V
authors.lastname: Carey
authors.forename: E
authors.initials: E
authors.lastname: Obarzanek
authors.forename: C M
authors.initials: CM
authors.lastname: Loria
authors.forename: S D
authors.initials: SD
authors.lastname: Anton
authors.forename: D H
authors.initials: DH
authors.lastname: Ryan
authors.forename: F L
authors.initials: FL
authors.lastname: Greenway
authors.forename: D
authors.initials: D
authors.lastname: Williamson
authors.forename: F M
authors.initials: FM
authors.lastname: Sacks
mesh_terms: D000328:Adult; D000368:Aged; D050218:Body Fat Distribution; D018752:Diet, Fat-Restricted; D059305:Diet, High-Fat; D004734:Energy Metabolism; D005260:Female; D006801:Humans; D015141:Los Angeles / Q000453:epidemiology; D008297:Male; D008404:Massachusetts / Q000453:epidemiology; D008875:Middle Aged; D009765:Obesity / Q000178:diet therapy* / Q000453:epidemiology / Q000503:physiopathology; D012146:Rest; D015431:Weight Loss