1. Department of Endocrinology, University of Groningen; University Medical Center Groningen; Groningen The Netherlands
2. Department of Bariatric and Metabolic Surgery; Medical Center Leeuwarden; Leeuwarden The Netherlands
3. European Center for Nutrition and Health (CENS); University of Lyon, 1 Civil Hospices of Lyon; Lyon France
4. Department of Gastroenterology; University Hospital Gasthuisberg; Leuven Belgium