title: Weight loss and body composition during the first postoperative year of a laparoscopic Roux-en-Y gastric bypass.
abstract: BACKGROUND
  Weight loss in patients undergoing gastric bypass should be primarily from fat mass (FM), minimizing the fat-free mass (FFM) loss. The aim of this study was to analyze changes in body weight and body composition during the first postoperative year in 50 morbidly obese patients undergoing a Laparoscopic Roux-en-Y gastric bypass (LRYGBP) at the Obesity Clinic of the ABC Medical Center.
  
  
  METHODS
  Patient's weight and body composition were obtained before surgery and 1 year later using bioelectrical impedance analysis (BIA). Weight, FM, FMM, and total body water (TBW) were measured before and 1 year after surgery. Changes in body composition were particularly analyzed.
  
  
  RESULTS
  There were 29 females and 21 males with mean age of 41 +/- 12 years. Mean BMI before surgery and 1 year after surgery was 44.4 +/- 7.4 kg/m(2) and 28.3+/-4.3 kg/m(2), respectively. The percentage of excess body weight loss at the 1-year period was 86% for women and 79.6% for men. The percentage of FM before surgery was 47.7 +/- 5.1, and 1 year later it was 28.8 +/- 8. The percentage of FFM was 66.5 +/- 16.5 before surgery and 58.3 +/- 13 at 1 year.
  
  
  CONCLUSIONS
  There is a significant weight loss in patients undergoing LRYGBP. Weight loss mainly occurs as a consequence of reduction in the FM with less impact on the FFM.
authors: The Obesity Clinic, American British Cowdray Medical Center, Sur 136 # 116 Colonia Las Américas, 01120, Mexico City, Mexico, herreram@quetzal.innsz.mx.
authors: Tatiana
authors: T
authors: Palazuelos-Genis
authors: Maureen
authors: M
authors: Mosti
authors: Sofía
authors: S
authors: Sánchez-Leenheer
authors: Rocío
authors: R
authors: Hernández
authors: Olivia
authors: O
authors: Garduño
authors: Miguel F
authors: MF
authors: Herrera
mesh_terms: D000328:Adult; D001823:Body Composition; D005260:Female; D015390:Gastric Bypass; D006801:Humans; D010535:Laparoscopy; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000503:physiopathology* / Q000601:surgery; D013997:Time Factors; D015431:Weight Loss