Professor Gerhard Prager is a highly experienced bariatric surgery specialist with over 3,000 operations for obesity treatment. He is the head of the Obesity Outpatient Clinic in Vienna General Hospital and head of the Metabolic Surgery Center in Confraternitaet Private Hospital. He is a member of several organizations such as the IFSO-European Chapter, the Austrian Obesity Association, the International Federation for the Surgery of Obesity and Metabolic Disorders, the Austrian Society of Surgery, the Austrian Society of Bariatric Surgery, and the American Society for Metabolic & Bariatric Surgery.