title: Effects of a very low calorie diet in the preoperative stage of bariatric surgery: a randomized trial.
abstract: BACKGROUND
  Preoperative bariatric patients can follow very low calorie diets (VLCD), reducing surgical risks. However, possible advantages of a liquid diet over one of normal consistency are controversial. This study investigated the effect of a liquid VLCD compared with one of normal consistency considering visceral fat (VF) loss and metabolic profile in preoperative clinically severe obese patients.
  
  
  METHODS
  This was a randomized, open-labeled, controlled clinical trial. Patients were divided into 2 groups: liquid diet and normal diet. Data were collected at baseline and 7 and 14 days after intervention. Information gathered was analyzed for loss of weight and VF, biochemical data, anthropometric data, and energy intake.
  
  
  RESULTS
  Fifty-seven patients consumed the liquid diet and 47 consumed the normal consistency diet. The liquid diet group lost significantly more weight (P<.0290) and VF (P<.0410) than the normal diet group. An inverse correlation occurred between VF loss and surgical time among the liquid diet group (r2=-.1302, P=.001). Additionally, there was a positive correlation between the percentage of excess weight loss and ketonuria (P=.0070). No between-group difference occurred regarding calorie intake.
  
  
  CONCLUSIONS
  Patients that consumed a liquid diet presented a positive effect on reducing VF and greater weight loss than the normal diet group. Both VLCDs presented benefits offering a protective effect during the preoperative stage.
authors.affiliation: Graduate Program in Human Nutrition, University of Brasilia, Brasilia, Brazil; Gastrocirurgica Clinic, Brasilia, Brazil. Electronic address: silvialeitefaria@brturbo.com.br.
authors.forename: Silvia Leite
authors.initials: SL
authors.lastname: Faria
authors.affiliation: Gastrocirurgica Clinic, Brasilia, Brazil.
authors.forename: Orlando Pereira
authors.initials: OP
authors.lastname: Faria
authors.affiliation: Graduate Program in Human Nutrition, University of Brasilia, Brasilia, Brazil; Gastrocirurgica Clinic, Brasilia, Brazil.
authors.forename: Mariane
authors.initials: M
authors.lastname: de Almeida Cardeal
authors.affiliation: Graduate Program in Human Nutrition, University of Brasilia, Brasilia, Brazil.
authors.forename: Marina Kiyomi
authors.initials: MK
authors.lastname: Ito
mesh_terms: D050153:Abdominal Fat / Q000000981:diagnostic imaging; D000328:Adult; D031204:Caloric Restriction; D004044:Dietary Proteins / Q000008:administration & dosage; D005260:Female; D015390:Gastric Bypass; D006801:Humans; D006815:Hunger; D010535:Laparoscopy; D008297:Male; D009767:Obesity, Morbid / Q000178:diet therapy* / Q000601:surgery*; D061646:Operative Time; D010349:Patient Compliance; D011300:Preoperative Care; D014463:Ultrasonography; D015431:Weight Loss
chemical_list: D004044:Dietary Proteins
keywords: Bariatric surgery; Liquid diet; Obesity; Very low calorie diet; Visceral fat