title: [Energy expenditure and body composition in severe and morbid obese women after gastric bypass].
abstract: BACKGROUND
  The effects of gastric bypass (GBP) on resting energy expenditure (REE) are not well known.
  
  
  OBJECTIVE
  To evaluate the changes in REE and its relationship with body composition in severe and morbid obese women before and six and twelve months after GBP.
  
  
  METHODS
  Twenty three women aged 37+/-10 years, with a body mass index of 44+/-4 kg/m(2), were evaluated before, six and twelve months after GBP. REE was measured in a Deltatrac indirect calorimeter and expressed as kcal/day Fat mass (EM), and fat free mass (EEM) were determined by double beam X-ray densitometry (DEXA).
  
  
  RESULTS
  Body weight reduction six and twelve months after GBP was 29.0+/-4.3 and 35.8+/-6.9%, respectively. The best predictor of weight reduction was initial weight (p <0.01). At six and twelve months, REE decreased by 291.7+/-260.0 and 353.8+/-378.4 kcal/day, respectively. In the same periods REE/kg body weight increased by 3.3 and 4.8 kcal/kg respectively, compared to baseline. REE/kg EEM was unchanged.
  
  
  CONCLUSIONS
  GBP was associated with significant changes in body composition after six and twelve months. However, despite weight reduction, resting energy expenditure per fat free mass unit did not change significantly.
authors.affiliation: Departamento de Nutrición, Facultad de Medicina, Universidad de Chile, Santiago, Chile. fcarrasc@med.uchile.cl
authors.forename: Fernando
authors.initials: F
authors.lastname: Carrasco
authors.forename: Pamela
authors.initials: P
authors.lastname: Rojas
authors.forename: Manuel
authors.initials: M
authors.lastname: Ruz
authors.forename: Anabella
authors.initials: A
authors.lastname: Rebolledo
authors.forename: Juana
authors.initials: J
authors.lastname: Codoceo
authors.forename: Jorge
authors.initials: J
authors.lastname: Lnostroza
authors.forename: Claudio
authors.initials: C
authors.lastname: Mizón
authors.forename: Karin
authors.initials: K
authors.lastname: Papapietro
authors.forename: Attila
authors.initials: A
authors.lastname: Csendes
authors.forename: Jorge
authors.initials: J
authors.lastname: Rojas
authors.forename: Fernando
authors.initials: F
authors.lastname: Pizarro
authors.forename: Manuel
authors.initials: M
authors.lastname: Olivares