The nutrition transition occurring in the World Health Organization South-East Asia Region, as a result of rapid urbanization and economic development, has perhaps made this region one of the epicentres of the diabetes epidemic. This review attempts to evaluate the role of diet and physical inactivity in the South-East Asia Region in promoting this epidemic and points to strategies to slow it down by lifestyle modification. The emerging new food-production technologies and supermarkets have made energy-dense foods more easily available. This includes refined carbohydrate foods like those with added sugars, and refined grains and unhealthy fats. In addition, increased availability of modern technology and motorized transport has led to decreased physical activity. South Asian diets tend to be based on high-carbohydrate foods, with a predominance of refined grains. All of these accentuate the risk of diabetes in people of this region, who already have a unique "south Asian phenotype". However, there is increasing evidence that altering diet by replacing refined cereals like white rice with whole grains (e.g. brown rice) and increasing physical activity can help to prevent diabetes in high-risk individuals. An urgent, concerted effort is now needed to improve diet quality and encourage physical activity, by introducing changes in policies related to food and built environments, and improving health systems to tackle noncommunicable diseases like diabetes.