Simon Heales is a University College London Professorial Research fellow, Consultant Clinical Scientist and Director of the Neurometabolic Unit based at the National Hospital (UCLH), Queen Square. His NHS laboratory provides highly specialised diagnostic and monitoring services for a range of conditions including disorders affecting mitochondrial and neurotransmitter metabolism. Previously, Professor Heales has also held positions, at Great Ormond Street Children’s Hospital as Head of the Enzyme Lab, Director of Newborn Screening and Chief of Laboratory Medicine. Underpinning his NHS activities, Professor Heales has an active research (basic and translational) programme focussing on development of better diagnostic methods, identification of new disease mechanisms and establishing new treatment strategies, e.g.by elucidating mechanisms responsible for the efficacy of medium chain fatty acid based ketogenic diets and their relationship to brain energy metabolism.