The study evaluates the gastric emptying by scintigraphy in patients that had bariatric surgery (RYGB of gastric sleeve) comparing patients with successful and unsuccessful weight loss and in patients before and after the placement of a duodenal-jejunal bypass liner.

Additional, after bariatric surgery gut hormones that influence the gastric emptying rate are determined.

Bariatric surgery reduces stomach volume and passage of foods through the gastrointestinal tract is altered. The satiety level often increases, which is probably caused by gut hormones. Patients response on different bariatric procedures varies widely and it is difficult to predict which patient responds well. Possibly, patients who have successful excess weight loss (EWL) two years after surgery have different gastric emptying rates compared to unsuccessful patients.

Changes in gut hormones after implantation of a duodenal-jejunal bypass liner were demonstrated in other studies. However, gastric emptying before and after placement of this liner is unknown.

Inclusion Criteria:

• Patients must be able to adhere to the study visit schedule and protocol requirements
• Patients must be able to give informed consent and the consent must be obtained prior to any study procedures
• Patients who had a follow-up period up till 2 years after bariatric surgery without any complications or
• Patients are eligible for DJBL implantation

Exclusion Criteria:

• Binge-eating or associated eating disorder
• Active drug or alcohol addiction
• Pregnancy or giving breast feeding
• Gluten allergy
• Inability to stop medication that affects the motility of the upper GI tract (anti-cholinergic drugs, prokinetics, theophylline, calcium blocking agents, opioids)
• Endocrine disease influencing gastric emptying (diabetes mellitus, hyper- or hypothyroidism). Type 2 diabetes mellitus is not an exclusion criterium for patients receiving the DJBL.