Bariatric Surgery By Adrienne Youdim, MD, David Geffen School of Medicine at UCLA Reviewed / Revised Aug 2021 | Modified Sep 2022 View Patient Education Indications Procedures Preoperative Evaluation Risks Prognosis Follow-up Key Points Topic Resources Body Mass Index (Quetelet's... Roux-en-Y gastric bypass... Adjustable gastric banding Bariatric surgery is the surgical alteration of the stomach, intestine, or both to cause weight loss.