1 Department of Nutrition & Dietetics, Guy's & St Thomas' NHS Foundation Trust, Westminster Bridge Road, London SE1 7EH, UK. Electronic address: elizabeth.weekes@gstt.nhs.uk.
2 Diabetes and Nutritional Sciences Division, Franklin-Wilkins Building, King's College London, Stamford Street, London SE1 9NH, UK. Electronic address: christine.baldwin@kcl.ac.uk.