Inclusion Criteria:  Age 18-65 years; BMI ≥40 kg/m2 or BMI ≥35 kg/m2 with obesity related comorbidity; Weight regain or insufficient weight loss (EWL<50% or TWL<20%)15,16 following RYGB; Multidisciplinary team screening at one of the bariatric centres; Informed consent and willing to enter the follow-up program.  Exclusion Criteria:  Failed Roux-en-Y gastric bypass due to anatomic, surgical reasons (gastric pouch dilatation >50 mL, gastro-gastric fistula, gastro-jejunostomy); Distalisation of RYGB is technical infeasible (judgment by surgeon); Inflammatory bowel disease, celiac disease, irritable bowel syndrome and other causes of chronic diarrhea; Severe concomitant disease (such as carcinomas and neurodegenerative disorders); Pregnant women; Noncompliance in follow-up or unwilling to undergo surgery; Inability of reading/understanding and filling out questionnaires.