Although overweight and obesity are increasingly seen as the key 'risk factors' for Type 2 diabetes mellitus (T2DM), the relationship between them is complex and not well understood. There are many 'risk factors' for T2DM, including ageing, genetics, previous gestational diabetes, a family history of the disease, etc. the interplay of which is not entirely clear. While weight gain is a common symptom of T2DM and the disease appears to be more prevalent among 'obese' people, individuals from a broad range of weights (including those considered 'healthy') can develop the disease. However, in recent years, the idea that fatness is the risk factor and/or central cause of T2DM has become increasingly prevalent and naturalized in popular, academic, and public health discourses in Australia. In these convergences, the complex etiology of the disease and limitations in current knowledge are blurred or reconstituted. To date, the potency of overweight and obesity as cultural signifiers for T2DM and its consequences has received little attention. Drawing on an analysis of government reports, journal articles, and media coverage published since 1998, this article sets out to trace and unpack some of the contours of these convergences, while recognizing their entanglement in earlier moralizing discourses, which continue to have considerable salience.