Modeling US adult obesity trends: a system dynamics model for estimating energy imbalance gap.
OBJECTIVE
We present a system dynamics model that quantifies the energy imbalance gap responsible for the US adult obesity epidemic among gender and racial subpopulations.


METHODS
We divided the adult population into gender-race/ethnicity subpopulations and body mass index (BMI) classes. We defined transition rates between classes as a function of metabolic dynamics of individuals within each class. We estimated energy intake in each BMI class within the past 4 decades as a multiplication of the equilibrium energy intake of individuals in that class. Through calibration, we estimated the energy gap multiplier for each gender-race-BMI group by matching simulated BMI distributions for each subpopulation against national data with maximum likelihood estimation.


RESULTS
No subpopulation showed a negative or zero energy gap, suggesting that the obesity epidemic continues to worsen, albeit at a slower rate. In the past decade the epidemic has slowed for non-Hispanic Whites, is starting to slow for non-Hispanic Blacks, but continues to accelerate among Mexican Americans.


CONCLUSIONS
The differential energy balance gap across subpopulations and over time suggests that interventions should be tailored to subpopulations' needs.
At the time of the study, Saeideh Fallah-Fini was with Johns Hopkins Global Center on Childhood Obesity, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD. Hazhir Rahmandad is with the Industrial and Systems Engineering Department, Virginia Tech, Falls Church, VA. Terry T.-K. Huang is with Department of Health Promotion, Social and Behavioral Health, University of Nebraska Medical Center, College of Public Health, Omaha. Regina M. Bures is with Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD. Thomas A. Glass is with Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health. Regina M. Bures is also a guest editor for this theme issue.
Saeideh
S
Fallah-Fini
Hazhir
H
Rahmandad
Terry T-K
TT
Huang
Regina M
RM
Bures
Thomas A
TA
Glass
D000328:Adult; D015992:Body Mass Index; D004032:Diet; D002149:Energy Intake; D004734:Energy Metabolism; D005260:Female; D006306:Health Surveys; D006801:Humans; D008297:Male; D008962:Models, Theoretical; D009765:Obesity / Q000453:epidemiology* / Q000208:ethnology; D044469:Racial Groups; D012737:Sex Factors; D014481:United States / Q000453:epidemiology