In an attempt to contain rising trends in obesity and associated chronic diseases, many governments have implemented a range of policies to promote healthy lifestyles. Evaluations of the cost-effectiveness and distributional impacts of such interventions are rare and narrow in terms of numbers of options considered. In this report, an economic analysis was developed jointly by the OECD and the WHO with the aim of strengthening the existing evidence-base on the efficiency of interventions to tackle unhealthy diets and sedentary lifestyles.