Based on current knowledge of the cost of disease treatment, future costs to the government National Health Service are projected. The model is developed in three steps: a regression analysis to project the future distribution of risk factors in the population, a microsimulation model to project the future disease burden associated with these risk factors, and an ex-post calculation to estimate public expenditures in current dollars associated with the projected future disease burden. The equations were then used to predict the future distribution of BMI categories from 2008 to 2050.