Bariatric surgery of morbid obesity was first located at Førde Central Hospital, but it is now an established treatment at several other hospitals in the health region (Voss Hospital (Helse Bergen), Haugesund Hospital (Helse Fonna) Stavanger University Hospital ((SUS) Helse Stavanger). Surgical methods vary between hospitals: Voss: sleeve gastrectomy, Haugesund: gastric bypass (Roux-en Y),SUS: gastric bypass (Roux-en Y); Førde: biliopancreatic diversion with duodenal switch (BPD / DS) and sleeve gastrectomy . The investigators have then in Helse-Vest a unique opportunity to examine the various clinical and metabolic effects from different surgical methods.