Sadaf Farooqi has fundamentally altered our understanding of human obesity. Her work was key to the discovery of the first mutations that cause human obesity, defining and characterising a range of previously undescribed genetic obesity syndromes, and establishing that the principal driver of obesity in these monogenic syndromes was a failure of the central control of appetite and satiety. She has been greatly committed to the translation of her research into patient benefit and has helped to change clinical attitudes and diagnostic practice world-wide. Obesity is one of the major public health threats facing the international community and Farooqi’s research has been critical in bringing real biological insights where these were previously lacking.