1. Medical Psychology and Medical Sociology; Leipzig University Medical Center, Integrated Research and Treatment Center Adiposity Diseases, Philipp-Rosenthal-Strasse 27; Leipzig 04103 Germany
2. Department of General Surgery; Asklepios Clinic, Suurheid 20; Hamburg 22559 Germany
3. Schön Klinik Hamburg Eilbek Bariatric Clinic, Dehnhaide 120; Hamburg 22081 Germany
4. Department of General, Visceral, Vascular and Pediatric Surgery; University Hospital, University of Würzburg, Oberdürrbacher Strasse 6; Würzburg 97080 Germany
5. Department of Visceral, Pediatric and Vascular Surgery; Hospital Konstanz, Luisenstrasse 7; Konstanz 78464 Germany
6. Core Unit Nutrition and Clinical Phenotyping; Leipzig University Medical Center, Integrated Research and Treatment Center Adiposity Diseases, Philipp-Rosenthal-Strasse 27; Leipzig 04103 Germany