Abstract for: Modeling Obesity Trends among U.S. Children: A System Dynamics Model for Estimating the Energy Imbalance Gap

This paper presents a population-level system dynamics model that quantifies the energy imbalance gap responsible for the obesity epidemic among U.S. children during the past four decades. Our system dynamics model divides the U.S. child population into subpopulations by gender and ethnicity. Each subpopulation is then further divided into four age groups and each age group into 14 body mass index (BMI) classes. Transition rates between these BMI classes are defined as a function of pediatric metabolic dynamics within each class according to existing validated models. The energy intake in each BMI class at any point in time within the last decades is estimated as a multiplication of the reference energy intake (the energy needed for normal growth) for children in that class by an energy gap multiplier. Through calibration, the energy gap multiplier for each gender-ethnicity-age-BMI subgroup is estimated by matching simulated BMI distributions for each subpopulation against data from NHANES using maximum likelihood estimation. Our results shed light on differential energy imbalance gaps across different subpopulations over time. The system dynamics approach creates a modeling platform to better understand intervention targets in different segments of children and upon which intervention strategies can be modeled and tested.