Weight loss surgery performed by experts in bariatric surgery: Dr. Hsin-Yi Chang and Dr. John Cheregi, the bariatric surgeon team at Advanced Bariatrics. Our offices in Barrington, Crystal Lake and Algonquin serve weight loss patients throughout Chicago and the surrounding suburbs. We perform Gastric Bypass surgery (Roux-en-Y), Gastric Sleeve surgery and Gastric Band surgery. Contact us today for a consultation or attend one of our seminars to learn more about the Advanced Bariatrics team and the life changing results we deliver for our medical weight loss patients.