In the ongoing debates surrounding the metabolic syndrome, perhaps the key issue is whether this cluster of medical disorders arises from obesity or insensitivity to insulin. The lack of consensus on the principal underlying unifying factor of the syndrome is illustrated by the history of its name: ‘plurimetabolic syndrome’, ‘syndrome X’, ‘deadly quartet’, ‘insulin resistance syndrome’, and ‘dysmetabolic syndrome’ are some of the attempts to label this multi-factorial condition. Gaetano Crepaldi and Stefania Maggi tell the story of the metabolic syndrome and of the many attempts to develop standardized diagnostic criteria to identify and treat it. As the authors point out, the many controversial issues surrounding this debate look set to ensure that this story is an unfinished one.