Confocal Laser Endomicroscopy Based Diet in Functional Dyspepsia (CLEFD)

Inclusion Criteria: Age 18-70 y/o (70 years included) Male or female subjects FD (PDS, EPS or overlap) according to Rome IV criteria Provide written informed consent to participate in the study Women of child-bearing potential agree to apply a highly effective method of birth control during the entire duration of the trial. Highly effective birth control is defined as those which result in a low failure rate (i.e., less than 1% per year) when used constantly and correctly such as implants, injectables, combined oral contraceptive method, or some intrauterine devices (IUDs), sexual abstinence, or vasectomized partner. Women of non-childbearing potential may be included if surgically sterile (tubal ligation or hysterectomy) or postmenopausal with at least 2 year without spontaneous menses. Subjects who are capable to understand the study and the questionnaires, and to comply with the study requirements. Exclusion Criteria: Pregnant or breastfeeding women History of major surgery of the gastrointestinal tract (cholecystectomy and uncomplicated appendectomy are allowed) Symptoms predominantly associated with irritable bowel syndrome or gastro-esophageal reflux disease IgE-mediated food allergies identified by immunocaps blood tests Known underlying organic gastrointestinal disease Current use of NSAIDs, proton-pump inhibitors, systemic histamine-receptor antagonists, mast cell stabilizers, corticosteroids, opioids (need to be stopped at least 2 weeks). Use of antibiotics in the past 6 weeks. Allergy to Fluorescein or Propofol Known celiac disease Following a diet, interfering with the study diet in opinion to the investigators