A metabolic-epidemiological microsimulation model to estimate the changes in energy intake and physical activity necessary to meet the Healthy People 2020 obesity objective

Objectives. We combined a metabolic and an epidemiological model of obesity to estimate changes in calorie intake and physical activity necessary to achieve the Healthy People 2020 objective of reducing adult obesity prevalence from 33.9% to 30.5%. Methods. We used the National Health and Nutrition Examination Survey (1999-2010) to construct and validate amicrosimulation model of the US population aged 10 years and older, for 2010 to 2020. Results. Obesity prevalence is expected to shift toward older adults, and disparities are expected to widen between White, higher-income groups and minority, lowerincome groups if recent calorie consumption and expenditure trends continue into the future. Although a less than 10% reduction in daily calorie intake or increase in physical activity would in theory achieve the Healthy People 2020 objective, no single population-level intervention is likely to achieve the target alone, and individual weight-loss attempts are even more unlikely to achieve the target. Conclusions. Changes in calorie intake and physical activity portend rising inequalities in obesity prevalence. These changes require multiple simultaneous population interventions.