A frequent late complication of RYGB is the dumping syndrome and a rare late complication is hyperinsulinaemic hypoglycemia (HH). Reported incidences of dumping syndrome range from 20 to 70% of the patients. Dumping is a condition where food enters the small bowel too rapidly and can be divided into early and late dumping. Early dumping is due to rapid gastric emptying and comprises intestinal and vasomotor symptoms within minutes after food ingestion. Late dumping occurs 1 to 3 hours after a meal and the symptoms are partly caused by hypoglycemia.