Impact of Bariatric Surgery on the Gut Environment

The purpose of this study is to investigate the impact of bariatric surgery on the gut health. Patients operated with Roux-en-Y gastric bypass or sleeve gastrectomy and obese patients who want too loose weight with a traditional weight-loss program, will be followed up for 1 year. In these patients, the investigators will measure toxicity parameters to understand better the health status of their colon after surgery. In a next phase, the measured toxicity will be linked with certain players that might cause this toxicity. Protein metabolites, formed from undigested protein by microbiota in the colon, are expected to be toxic agents for the colon. Therefore, the investigators will investigate the fate of ingested protein once the surgery patients are metabolically stabilized.