Christine Stier, MD, specialist in surgery and general medicine with an additional qualification in nutritional medicine. The physician was jointly responsible for the establishment of several obesity centers and has introduced innovative bariatric endoscopic techniques in Germany. Dr. Stier has already been honored with numerous awards for her scientific publications.Sonja Chiappetta, MD, specialist in surgery, section head of the Center of Excellence in Bariatric and Metabolic Surgery at the Ospedale Evangelico Betania, Naples.Christine Stier, MD, and Sonja Chiappetta, MD, are internationally recognized and scientifically renowned bariatric surgeons. They have worked and researched together in Frankfurt and Offenbach at the first German Center of Excellence for Metabolic and Bariatric Surgery under the direction of Prof. Rudolf Weiner. Today, they both head their own excellence-certified departments - Dr. Stier in Mannheim and Dr. Chiappetta in Naples (Italy).