Since its conception, the metabolic syndrome has received worldwide recognition as a useful clinical aid for predicting cardiovascular risk. The earliest definition, which included risk factors such as insulin resistance, hyperglycemia, hypertension, and cholesterol, has undergone many transformations. Two revisions have focused on visceral adiposity as an essential component of the syndrome, particularly in Asian populations. The Japanese national guidelines have also suggested that abnormalities in adipose tissue metabolism are an underlying molecular cause of the syndrome. In addition, emerging evidence suggests that lowering the threshold of waist circumference in Asian populations increases the prevalence of the metabolic syndrome. Inevitably, this widening of the threshold will capture more patients at risk of cardiovascular events. The aim of this Article is to consider the country-specific impact of the metabolic syndrome, using the evolution of the definition in Japan as a model.