1. Department of Medicine, Centre for Obesity Research, Rayne Institute, University College London, London, UK
2. Bariatric Centre for Weight Management and Metabolic Surgery, University College London Hospital (UCLH) Bariatric Centre for Weight Management and Metabolic Surgery, University College London Hospital, London, UK
3. Bariatric Centre for Weight Management and Metabolic Surgery, National Institute of Health Research, UCLH Biomedical Research Centre, London, UK