Introduction As the prevalence of chronic diseases continues to climb, the challenges of quantifying the impact of this epidemic to inform decision makers becomes more urgent. Drawing on experiences of work in England, USA, Brazil, Mexico and Russian Federation we will demonstrate how the application of micro simulation modelling can lead to a systematic understanding of the associated morbidities, economic burden and inform policy makers form effective strategies and build the political will for change.

Method The application of micro-simulation modelling techniques to understand the future impact of changes in trends in tobacco consumption and obesity rates and the potential impact of policy interventions.

Results The work initially undertaken for the Foresight Tackling Obesities research was instrumental in galvanising a cross government strategy in England, Healthy Weight, Healthy Lives, subsequent outputs from the simulations in the USA, Brazil, Mexico and Russian Federation should also inform policy in those countries.

Conclusion Morbidity and the economic burden of chronic disease is a practical metric for comparative assessment of health risks, as exemplified by its use by international organizations such as the World Bank, the WHO and the Organisation Economic Co-operation and Development. Nonetheless, the applications for simulation models of morbidity consequences of chronic disease can well go beyond projecting the growth of the problem to the society. A modelling framework provides a useful infrastructure for the comparative evaluation of the effectiveness and return-on-investment of potential policies aimed to alter the drivers and determinants of obesity epidemic.