The obesity epidemic continues to escalate each year in the United States more than anywhere else in the world. The existing pharmaceutical and other nonsurgical treatments for morbid obesity produce suboptimal physiologic outcomes compared with those of Roux-en-Y gastric bypass (RYGB) surgery. RYGB has been the gold standard of bariatric surgery because the beneficial long-term outcomes, which include sustainable weight loss and type 2 diabetes mellitus (T2DM) resolution, are far superior to those obtained with other bariatric surgeries. However, the current understanding of RYGB's mechanisms of actions remains limited and incomplete. There is an urgent need to understand these mechanisms as gaining this knowledge may lead to the development of innovative and less invasive procedures and/or medical devices, which can mirror the favorable outcomes of RYGB surgery. In this review, we highlight current observations of the metabolic and physiologic events following RYGB, with a particular focus on the role of the anatomical reconfiguration of the gastrointestinal tract after RYGB.


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