BACKGROUND:Early and late dumping are complications of gastric bypass surgery. Early dumping occurs within an hour after eating, when the emptying of food into the small intestine triggers rapid fluid shifts into the intestinal lumen and the release of gastrointestinal hormones, resulting in gastrointestinal and vasomotor symptoms. Late dumping occurs between 1 and 3 hours after carbohydrate ingestion and is caused by an exaggerated insulin release, resulting in hypoglycemia. Almost no data are currently available on the prevalence of early and late dumping or their impact on health-related quality of life (QoL). OBJECTIVES:To study the prevalence of early and late dumping in a large population of patients having undergone a primary Roux-en-Y gastric bypass (RYGB) and its effect on QoL. SETTING:Cross-sectional study at a single bariatric department in the Medical Center Leeuwarden, The Netherlands between 2008 and 2011. METHODS:In 2013, this descriptive cohort study approached by email or post all patients who underwent a primary RYGB in the setting between 2008 and 2011 in one hospital. These patients were asked to fill in standardized questionnaires measuring their QoL (RAND-36), anxiety and depression (HADS), fatigue (MFI-20) and any disease specific indicators of early and late dumping syndrome. RESULTS:The questionnaire was completed and returned by 351 of 613 patients (57.1%) and 121 nonobese volunteers. Participants were mostly female (80%), aged 42 (40-54 years), with an excess weight loss of 76.8% [IQR 61-95] after RYGB surgery 2.3 [ IQR 1.6-3.4] years earlier. Self-reported complaints of moderate to severe intensity suggestive of early and late dumping were present in 18.8% and 11.7% of patients, respectively. Patients with early and late dumping demonstrated significantly lower scores on the RAND-36 and HADS compared with patients without dumping. No differences were seen in the MFI-20 scores between patients with or without early and late dumping. CONCLUSION:In this descriptive cohort, self-reported complaints suggestive of early and late dumping of moderate-to-severe intensity were, respectively, 18.8% and 11.7% in a cohort after primary gastric bypass surgery. These complaints were associated with markedly reduced health-related QoL.