Department of Surgery, Møre and Romsdal Hospital trust, Ålesund, Norway. Centre for Obesity Research, Clinic of Surgery, St. Olav's University Hospital, Trondheim, Norway. Department of Clinical and Molecular Medicine, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway. Faculty of Social Science and History, Volda University College, Volda, Norway. Clinic of Surgery, Namsos Hospital, Nord-Trøndelag Hospital Trust, Namsos, Norway. Department of Research and Innovation, Møre and Romsdal Hospital Trust, Ålesund, Norway. Norwegian National Advisory Unit on Advanced Laparoscopic Surgery, Clinic of Surgery, St. Olav's University Hospital, Trondheim, Norway. Department of Psychology, Norwegian University of Science and Technology, Trondheim, Norway.