title: Resting metabolic rate and postabsorptive substrate oxidation in morbidly obese subjects before and after massive weight loss.
abstract: OBJECTIVE
  To investigate the changes of resting metabolic rate (RMR) and postabsorptive oxidation of carbohydrates (CHO), lipids (LIP) and proteins (PT) in morbidly obese subjects after long-term stable massive weight reduction.
  
  
  METHODS
  Longitudinal, intervention study of a bilio-pancreatic by-pass.
  
  
  METHODS
  Ten (Four men, six women) obese subjects (BMI: 53.7 +/- 2.1 kg/m2, mean +/- s.e.m.) and 12 (three men, nine women) control subjects (BMI: 21.4 +/- 1.0 kg/m2).
  
  
  METHODS
  RMR and substrates oxidation (indirect calorimetry), body composition (bioelectrical impedance), plasma concentrations of glucose, FFA, insulin and thyroid hormones before (T0, prior to surgery), during (T1: 1-3 months, and T2: 9-16 months following surgery) and after (T3: 36-42 months following surgery) massive weight loss.
  
  
  RESULTS
  At T3 BMI proved to be stably reduced to 32.9 +/- 1.3 (P < 0.0001). The RMR progressively reduced both in absolute value (T3: -2566 kJ/24 h; P < 0.0001 vs T0) and normalized for fat-free mass (FFM; T0: 123 +/- 3.8, T1: 109 +/- 3.3, T2: 112 +/- 7.1, T3: 105 +/- 4.6 kJ/kg-FFM.24 h; P < 0.05). At T3 the normalized RMR became significantly lower than the corresponding value of a control group (118 +/- 2.5 kJ/kg-FFM.24 h; P < 0.01). The long term trend in substrates oxidation showed that CHO oxidation increased while LIP oxidation decreased; PT oxidation did not significantly change for the whole of the study.
  
  
  CONCLUSIONS
  Previously morbid obese subjects have an energy sparing metabolism and a normal postabsorptive oxidation of LIP and CHO.
authors.affiliation: Institute of Clinica Medica, University of Palermo, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Buscemi
authors.forename: G
authors.initials: G
authors.lastname: Caimi
authors.forename: S
authors.initials: S
authors.lastname: Verga
mesh_terms: D000042:Absorption; D000328:Adult; D001481:Basal Metabolism; D015904:Biliopancreatic Diversion; D015992:Body Mass Index; D002153:Calorimetry, Indirect; D050260:Carbohydrate Metabolism; D005260:Female; D006801:Humans; D007700:Kinetics; D050356:Lipid Metabolism; D008137:Longitudinal Studies; D008297:Male; D009767:Obesity, Morbid / Q000378:metabolism* / Q000601:surgery*; D010084:Oxidation-Reduction; D015431:Weight Loss