title: Medical weight loss versus bariatric surgery: does method affect body composition and weight maintenance after 15% reduction in body weight?
abstract: OBJECTIVE
  The aim of this study was to investigate body composition changes in fat mass (FM) to lean body mass (LBM) ratios following 15% body weight loss (WL) in both integrated medical treatment and bariatric surgery groups.
  
  
  METHODS
  Obese patients (body mass index [BMI] 46.6 ± 6.5 kg/m(2)) who underwent laparoscopic gastric bypass surgery (BS), were matched with 24 patients undergoing integrated medical and behavioral treatment (MT). The BS and MT groups were evaluated for body weight, BMI, body composition, and waist circumference (WC) at baseline and after 15% WL.
  
  
  RESULTS
  Following 15% body WL, there were significant decreases in %FM and increased %LBM (P < 0.0001). Additionally, both groups saw 76% of WL from FM, and 24% from LBM indicating a 3:1 ratio of FM to LBM loss during the first 15% reduction in body weight. Finally, no significant differences (P = 0.103) between groups for maintenance of WL at 1 y were found. For both groups, baseline FM was found to be negatively correlated with percentage of weight regained (%WR) at 1 y post-WL (r = -0.457; P = 0.007). Baseline WC and rate of WL to 15% were significant predictors of %WR only in the BS group (r = 0.713; P = 0.020).
  
  
  CONCLUSIONS
  If followed closely by professionals during the first 15% body WL, patients losing 15% weight by either medical or surgical treatments can attain similar FM:LBM loss ratios and can maintain WL for 1 y.
authors.affiliation: Department of Individual, Family, and Community Education, University of New Mexico, Albuquerque, New Mexico, USA. Electronic address: mkulovi@unm.edu.
authors.forename: Michelle G
authors.initials: MG
authors.lastname: Kulovitz
authors.forename: Deborah
authors.initials: D
authors.lastname: Kolkmeyer
authors.forename: Carole A
authors.initials: CA
authors.lastname: Conn
authors.forename: Deborah A
authors.initials: DA
authors.lastname: Cohen
authors.forename: Robert T
authors.initials: RT
authors.lastname: Ferraro
mesh_terms: D000328:Adult; D000368:Aged; D001823:Body Composition / Q000502:physiology*; D015992:Body Mass Index; D005260:Female; D015390:Gastric Bypass; D006801:Humans; D010535:Laparoscopy; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D009516:New Mexico; D009765:Obesity / Q000601:surgery; D012189:Retrospective Studies; D015431:Weight Loss / Q000502:physiology*
keywords: Bariatric surgery; Body composition; Fat mass; Lean mass; Obesity; Weight loss; Weight maintenance