Current Obesity Reports

, Volume 4, Issue 2, pp 262–268 | Cite as

What is the Mechanism Behind Weight Loss Maintenance with Gastric Bypass?

  • Saurav Chakravartty
  • Daniele Tassinari
  • Angelo Salerno
  • Emmanouil Giorgakis
  • Francesco RubinoEmail author
Obesity Treatment (CM Apovian, Section Editor)
Part of the following topical collections:
  1. Topical Collection on Obesity Treatment


Obesity is an epidemic on the rise. With the failure of non-surgical strategies, bariatric surgery has emerged as the most effective therapeutic option for the treatment of severe obesity. Among various surgical options, Roux-en-Y gastric bypass (RYGB) results in sustained weight loss and profound metabolic improvements. The traditional view that gastric bypass and bariatric surgery in general works primarily through restriction/malabsorption of nutrients has become obsolete. It is now increasingly recognised that its mechanisms of action are primarily physiologic, not mechanic. In fact, clinical and translational studies over the last decade have shown that a number of gastrointestinal mechanisms, including changes in gut hormones, neural signalling, intestinal flora, bile acid and lipid metabolism can play a significant role in the effects of this procedure on energy homeostasis. The clinical efficacy and mechanisms of action of RYGB provide a compelling evidence for the role of the gastrointestinal tract in the regulation of appetite and satiety, body weight and glucose metabolism. This review discusses the physiologic changes that occur after RYGB and that contribute to its mechanisms of action.


Gastric bypass Weight loss Bariatric surgery Gut hormones Bile acids Microbiota Glucose metabolism 



The authors thank Ileana Geogloman, M.D. for her help with the review of recent literature.

Compliance with Ethics Guidelines

Conflict of Interest

Saurav Chakravartty, Daniele Tassinari, Angelo Salerno and Emmanouil Giorgakis declare that they have no conflict of interest.

Francesco Rubino serves as scientific advisory board member for NGM Biopharmaceutics and Fractyl. He also received consulting honoraria from Covidien and Ethicon Endosurgery.

Human and Animal Rights and Informed Consent

This article does not contain any studies with human or animal subjects performed by any of the authors.


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Copyright information

© Springer Science+Business Media New York 2015

Authors and Affiliations

  • Saurav Chakravartty
    • 1
  • Daniele Tassinari
    • 1
  • Angelo Salerno
    • 1
  • Emmanouil Giorgakis
    • 1
  • Francesco Rubino
    • 1
    Email author
  1. 1.Bariatric and Metabolic Surgery, Division of Diabetes and Nutritional SciencesKing’s College London and King’s College HospitalLondonUK

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