Send to:

Choose Destination
See comment in PubMed Commons below
J Clin Endocrinol Metab. 2013 Sep;98(9):3776-84. doi: 10.1210/jc.2013-1087. Epub 2013 Jul 3.

Enhanced thermic effect of food after Roux-en-Y gastric bypass surgery.

Author information

  • 1Obesity Center, Cantonal Hospital 9016 St. Gallen, 9016 St. Gallen, Switzerland.



The mechanisms of weight loss after Roux-en-Y gastric bypass (RYGB) surgery are incompletely understood.


Our objective was to investigate changes in metabolic processing of ingested food that may contribute to the weight-reducing effect of RYGB surgery.


This was a cross-sectional case-control study at the Interdisciplinary Obesity Center, Cantonal Hospital St. Gallen, St. Gallen, Switzerland.


Ten formerly obese women (mean ± SEM body mass index [BMI] = 26.6 ± 0.9 kg/m(2)) who had undergone RYGB surgery 41.9 ± 9.7 months before, 8 severely obese women (BMI = 40.8 ± 2.0 kg/m(2)), and 10 lean women (BMI = 20.9 ± 0.6 kg/m(2)).


Intervention was a standardized liquid meal test.


The thermic effect of food (TEF), respiratory quotient, and circulating levels of glucose, insulin, and C-peptide were assessed before and repeatedly during the first 90 minutes after the ingestion of a standardized liquid mixed meal containing 39.2 g carbohydrates, 15.4 g protein, and 2.8 g fat.


TEF area under curve (0-90 minutes) was significantly greater in RYGB patients than in severely obese and lean women (both P < .01). After ingestion of the mixed meal, the respiratory quotient increased to significantly greater values in the RYGB patients than in the severely obese and lean group (P < .001 for ANOVA time × group interaction). Also, the postprandial rise in circulating glucose, insulin, and C-peptide levels was remarkably higher in the RYGB patients than in the other 2 groups (all P < .001 for ANOVA time × group interaction).


Data demonstrate an enhanced TEF after RYGB surgery. Although this observation likely contributes to the weight-reducing effects of the surgery, data also point to an altered metabolic processing of food in RYGB patients characterized by an enhanced glucose absorption and postprandial carbohydrate oxidation.

[PubMed - indexed for MEDLINE]
PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Atypon
    Loading ...
    Write to the Help Desk