Effects of Posture and Meal Volume on Gastric Emptying, Intestinal Transit, Oral Glucose Tolerance, Blood Pressure and Gastrointestinal Symptoms After Roux-en-Y Gastric Bypass

Nam Q. Nguyen, Tamara L. Debreceni, Carly M. Burgstad, Judith M. Wishart, Max Bellon, Chris K. Rayner, Gary A. Wittert, Michael Horowitz

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28 Citations (Scopus)


Background: The purpose of this study is to determine the effects of posture and drink volume on gastric/pouch emptying (G/PE), intestinal transit, hormones, absorption, glycaemia, blood pressure and gastrointestinal (GI) symptoms after gastric bypass (Roux-en-Y gastric bypass (RYGB)). Methods: Ten RYGB subjects were studied on four occasions in randomized order (sitting vs. supine posture; 50 vs. 150 ml of labelled water mixed with 3 g 3-O-methyl-d-glucose (3-OMG) and 50 g glucose). G/PE, caecal arrival time (CAT), blood glucose, plasma insulin, glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), peptide YY (PYY), 3-OMG, blood pressure, heart rate and GI symptoms were assessed over 240 min. Controls were ten volunteers with no medical condition or previous abdominal surgery, who were studied with the 150-ml drink in the sitting position. Results: Compared to controls, PE (P < 0.001) and CAT (P < 0.001) were substantially more rapid in RYGB subjects. In RYGB, PE was more rapid in the sitting position (2.5 ± 0.7 vs. 16.6 ± 5.3 min, P = 0.02) and tends to be faster after 150 ml than the 50-ml drinks (9.5 ± 2.9 vs. 14.0 ± 3.5 min, P = 0.16). The sitting position and larger volume drinks were associated with greater releases of insulin, GLP-1 and PYY, as well as more hypotension (P < 0.01), tachycardia (P < 0.01) and postprandial symptoms (P < 0.001). Conclusions: Pouch emptying, blood pressure and GI symptoms after RYGB are dependent on both posture and meal volume.

Original languageEnglish
Pages (from-to)1392-1400
Number of pages9
JournalObesity Surgery
Issue number8
Publication statusPublished or Issued - 1 Aug 2015


  • Gastric emptying
  • Gastrointestinal hormones
  • Glucose absorption
  • Posture
  • Pouch
  • Roux-en-Y gastric bypass

ASJC Scopus subject areas

  • Surgery
  • Endocrinology, Diabetes and Metabolism
  • Nutrition and Dietetics

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