title: Effect on Nitrogen Balance, Thermogenesis, Body Composition, Satiety, and Circulating Branched Chain Amino Acid Levels up to One Year after Surgery: Protocol of a Randomized Controlled Trial on Dietary Protein During Surgical Weight Loss.
abstract: BACKGROUND
  Bariatric surgery (BS), the most effective treatment for severe obesity, typically results in 40-50 kg weight loss in the year following the surgery. Beyond its action on protein metabolism, dietary protein intake (PI) affects satiety, thermogenesis, energy efficiency, and body composition (BC). However, the required amount of PI after surgical weight loss is not known. The current daily PI recommendation for diet-induced weight loss is 0.8 g/kg ideal body weight (IBW) per day, but whether this amount is sufficient to preserve fat-free mass during active surgical weight loss is unknown.
  
  
  OBJECTIVE
  To evaluate the effect of a 3-month dietary protein supplementation (PS) on nitrogen balance (NB), BC, energy expenditure, and satiety in women undergoing either gastric bypass or vertical sleeve gastrectomy.
  
  
  METHODS
  In this randomized prospective study, participants will be randomized to a high protein supplementation group (1.2 g/kg IBW per day) or standard protein supplementation group (0.8 g/kg IBW per day) based on current guidelines. Outcome measures including NB, BC, circulating branched chain amino acids, and satiety, which will be assessed presurgery, and at 3-months and 12-months postsurgery.
  
  
  RESULTS
  To date, no studies have examined the effect of dietary PS after BS. Current guidelines for PI after surgery are based on weak evidence.
  
  
  CONCLUSIONS
  The results of this study will contribute to the development of evidence-based data regarding the safe and optimal dietary PI and supplementation after BS.
  
  
  BACKGROUND
  Clinicaltrials.gov NCT02269410; http://clinicaltrials.gov/ct2/show/NCT02269410 (Archived by WebCite at http://www.webcitation.org/6m2f2QLeg).
authors.affiliation: Institut Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.
authors.forename: Violeta
authors.identifier: http://orcid.org/0000-0001-8954-1206
authors.initials: V
authors.lastname: Moizé
authors.affiliation: Obesity Research Center, Department of Medicine, Columbia University, New York, NY, United States.
authors.forename: Xavier
authors.identifier: http://orcid.org/0000-0003-2207-2008
authors.initials: X
authors.lastname: Pi-Sunyer
authors.affiliation: Institut Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.
authors.forename: Josep
authors.identifier: http://orcid.org/0000-0002-4564-4518
authors.initials: J
authors.lastname: Vidal
authors.affiliation: Queens College, City University of New York, New York, NY, United States.
authors.forename: Patricia
authors.identifier: http://orcid.org/0000-0002-3718-0119
authors.initials: P
authors.lastname: Miner
authors.affiliation: Unité de Nutrition Humaine, Clermont Universite, Université d'Auvergne, Clermont-Ferrand, France.
authors.forename: Yves
authors.identifier: http://orcid.org/0000-0002-3999-1599
authors.initials: Y
authors.lastname: Boirie
authors.affiliation: Obesity Research Center, Department of Medicine, Columbia University, New York, NY, United States.
authors.forename: Blandine
authors.identifier: http://orcid.org/0000-0001-8255-3175
authors.initials: B
authors.lastname: Laferrère
keywords: BCAA; bariatric surgery; body composition; nitrogen balance; protein intake; satiety