Department of Psychology, Lund University, Lund, Sweden; Childhood Obesity Unit, Skåne University Hospital, Malmö, Sweden. Electronic address: kajsa.jarvholm@psy.lu.se. National Childhood Obesity Centre, Karolinska University Hospital, Stockholm, Sweden; Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden. Finnish Institute for Health and Welfare, Helsinki, Finland. Department of Medicine, Solna, Clinical Epidemiology Division, Karolinska Institutet, Stockholm, Sweden. Department of Paediatrics, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden. Institute of Clinical Sciences, and Institute of Health and Care Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden; Department of Surgery, Region Västra Götaland, Sahlgrenska University Hospital, Gothenburg, Sweden. Department of Surgery, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden. Welsh Institute of Metabolic and Obesity Surgery, Morriston Hospital, Swansea, UK; Swansea University Medical School, Swansea University, Swansea, UK. Department of Paediatrics, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden; Regional Obesity Center, Region Västra Götaland, Sahlgrenska University Hospital, Gothenburg, Sweden. Childhood Obesity Unit, Skåne University Hospital, Malmö, Sweden; Department of Biomedical and Clinical Sciences and Wallenberg Center for Molecular Medicine, Linköping University, Linköping, Sweden.