Over recent decades, there has been a worldwide increase in the number of people with obesity – currently around 300 million according to the International Obesity Task Force – and there are no signs of a slow-down. Furthermore, rates of overweight and obesity in adults and children are rising dramatically in developing countries. A large and growing body of evidence points to the transformation of lifestyles worldwide – over-consumption of energy-dense food and decreased physical activity – as the driving force behind this pandemic.