Department of Nutritional Sciences, King's College London, London, United Kingdom; Department of Nutrition and Dietetics, Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom; Adult Inherited Metabolic Diseases, Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom. Electronic address: sarah.firman@gstt.nhs.uk. Department of Nutritional Sciences, King's College London, London, United Kingdom; Centre for Human and Applied Physiological Sciences, King's College London, London, United Kingdom. Department of Nutritional Sciences, King's College London, London, United Kingdom; School of Food and Nutritional Sciences, University College Cork, College Road, Cork, Ireland. Adult Inherited Metabolic Diseases, Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom.