Assistance Publique Hôpitaux de Paris, Nutrition Department, Pitié-Salpêtrière Hospital, Paris, France; Sorbonne Université, INSERM, NutriOmics Research Unit, Paris, France. Division of Pediatric Endocrinology, Department of Pediatrics, Sophia Children's Hospital and Obesity Center CGG, Erasmus University Medical Center, Rotterdam, Netherlands. Department of Pediatrics and Pediatric Endocrinology, Universidad Autónoma de Madrid, University Hospital Niño Jesús, CIBER "Fisiopatología de la obesidad y nutrición" (CIBEROBN), Instituto de Salud Carlos III, IMDEA Institute, Madrid, Spain. Peel Memorial Hospital, Toronto, ON, Canada. Department of Pediatrics and Department of Medicine, Columbia University, New York, NY, USA. Rhythm Pharmaceuticals, Boston, MA, USA. Department of Pediatric and Adolescent Endocrinology, Ghent University Hospital, Ghent, Belgium. Wellcome-MRC Institute of Metabolic Science and NIHR Cambridge Biomedical Research Centre, University of Cambridge, Cambridge, UK. Université de la Réunion, Unité Transversale de Nutrition Clinique, CHU de la Réunion, Réunion, France. Division of Pediatric Endocrinology and Diabetes, Center for Rare Endocrine Diseases, Department of Pediatrics and Adolescent Medicine, University of Ulm, Ulm, Germany. Institute for Experimental Pediatric Endocrinology, Charité Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany; Department for Pediatric Endocrinology and Diabetology, Charité Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany. HonorHealth Bariatric Center, Scottsdale, AZ, USA. Division of Pediatric Endocrinology and Diabetes, Center for Rare Endocrine Diseases, Department of Pediatrics and Adolescent Medicine, University of Ulm, Ulm, Germany. Electronic address: martin.wabitsch@uniklinik-ulm.de. Institute for Experimental Pediatric Endocrinology, Charité Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany. Electronic address: peter.kuehnen@charite.de.