The Institute of Economic Affairs, a UK think tank, raised an important issue yesterday (18 August) when it insisted a decline in physical activity is the "root cause" of the obesity epidemic. The IEA research aims to debunk the widespread belief that our widening girths can largely be attributed to calorie consumption. However, while lifestyle factors are central to the obesity issue, Katy Askew suggests that a holistic approach - in which the food industry plays a central role - is needed to combat the problem.