Commentary All editorial matter in CMAJ represents the opinions of the authors and not necessarily those of the Canadian Medical Association.

Many countries around the world — Canada is noexception — are alarmed at the rising incidenceof type 2 diabetes and are especially concerned about its earlier age of onset.1 The underlying reason for this dire predicament appears to be the increasing preva-lence of obesity in the population and, more precisely, the dysfunctional state of the adipose tissue associated with obesity.2 It is critical to implement strategies for safe and ef-fective prevention or treatment of obesity in order to reduce metabolic and vascular disease.3,4 For a better understanding of the epidemiologic relation between obesity and type 2 diabetes, many clinical investiga-tors have turned to the detailed databases generated by prospective cohort studies. With such large-scale study popu-lations, “gold-standard ” approaches to assess the amount and location of body fat, such as underwater weighing and magnetic resonance imaging, are not practical. Instead, co