title: Energy and macronutrient intake after gastric bypass for morbid obesity: a 3-y observational study focused on protein consumption.
abstract: BACKGROUND
  The effect of a Roux-en-Y gastric bypass (RYGB) on body weight has been amply documented, but few studies have simultaneously assessed the evolution of energy and macronutrient intakes, energy expenditure, and changes in body composition over time after an RYGB.
  
  
  OBJECTIVE
  We evaluated energy and macronutrient intakes, body composition, and the basal metabolic rate (BMR) in obese female patients during the initial 3 y after an RYGB.
  
  
  METHODS
  Sixteen women with a mean ± SEM body mass index (in kg/m(2)) of 44.1 ± 1.6 were included in this prospective observational study. The women were studied on 6 different occasions as follows: before and 1, 3, 6, 12 (n = 16), and 36 (n = 8) mo after surgery. On each occasion, food intake was evaluated from 4- or 7-d dietary records, body composition was assessed with the use of bio-impedancemetry, and energy expenditure was measured with the use of indirect calorimetry.
  
  
  RESULTS
  Body weight evolution showed the typical pattern reported after an RYGB. Total energy intake was 2072 ± 108 kcal/d at baseline and decreased to 681 ± 58 kcal/d at 1 mo after surgery (P < 0.05 compared with at baseline). Total energy intake progressively increased to reach 1240 ± 87 kcal/d at 12 mo after surgery (P < 0.05 compared with at 1 mo after surgery) and 1448 ± 57 kcal/d at 36 mo after surgery (P < 0.05 compared with at 12 mo after surgery). Protein intake was 87 ± 4 g/d at baseline and ± 2 g/d 1 mo after surgery (P < 0.05 compared with at baseline) and increased progressively thereafter to reach 57 ± 3 g/d at 36 mo after surgery (P < 0.05 compared with at 1 mo after surgery). Carbohydrate and fat intakes over time showed similar patterns. Protein intake from meat and cheese were significantly reduced early at 1 mo after surgery but increased thereafter (P < 0.05). The BMR decreased from 1.12 ± 0.04 kcal/min at baseline to 0.93 ± 0.03, 0.86 ± 0.03, and 0.85 ± 0.04 kcal/min at 3, 12, and 36 mo after surgery, respectively (all P < 0.05 compared with at baseline).
  
  
  CONCLUSIONS
  Total energy, carbohydrate, fat, and protein intakes decreased markedly during the initial 1-3 mo after an RYGB, whereas the BMR moderately decreased. The reduction in protein intake was particularly severe at 1 mo after surgery, and protein intake increased gradually after 3-6 mo after surgery. This trial was registered at clinicaltrials.gov as NCT01891591.
authors.affiliation: Cardio-Metabolic Centre, Hôpital of Broye, Estavayer-le-Lac, Switzerland;
authors.forename: Vittorio
authors.initials: V
authors.lastname: Giusti
authors.affiliation: Department of Physiology, University of Lausanne, Lausanne, Switzerland; and.
authors.forename: Fanny
authors.initials: F
authors.lastname: Theytaz
authors.affiliation: Service of Endocrinology, Diabetes and Metabolism, and.
authors.forename: Véronique
authors.initials: V
authors.lastname: Di Vetta
authors.affiliation: Service of Endocrinology, Diabetes and Metabolism, and.
authors.forename: Muriel
authors.initials: M
authors.lastname: Clarisse
authors.affiliation: Department of Surgery, Lausanne University Hospital, Lausanne, Switzerland.
authors.forename: Michel
authors.initials: M
authors.lastname: Suter
authors.affiliation: Cardio-Metabolic Centre, Hôpital of Broye, Estavayer-le-Lac, Switzerland; Department of Physiology, University of Lausanne, Lausanne, Switzerland; and Service of Endocrinology, Diabetes and Metabolism, and luc.tappy@unil.ch.
authors.forename: Luc
authors.identifier: http://orcid.org/0000-0001-8469-4692
authors.initials: L
authors.lastname: Tappy
mesh_terms: D000328:Adult; D001481:Basal Metabolism; D004032:Diet; D004040:Dietary Carbohydrates / Q000008:administration & dosage*; D004041:Dietary Fats / Q000008:administration & dosage*; D004044:Dietary Proteins / Q000008:administration & dosage*; D002149:Energy Intake; D005260:Female; D015390:Gastric Bypass / Q000009:adverse effects*; D006801:Humans; D009767:Obesity, Morbid / Q000601:surgery*; D011446:Prospective Studies
chemical_list: D004040:Dietary Carbohydrates; D004041:Dietary Fats; D004044:Dietary Proteins
keywords: body composition; energy intake; gastric bypass; protein intake; weight loss