Effectiveness of Policies and Programs to Combat Adult Obesity: a Systematic Review

Background This systematic review identifies programs, policies, and built-environment changes targeting prevention and control of adult obesity and evaluates their effectiveness. Methods We searched PubMed, CINAHL, PsycINFO, and EconLit from January 2000 to March 2018. We included natural experiment studies evaluating a program, policy, or built-environment change targeting adult obesity and reporting weight/body mass index (BMI). Studies were categorized by primary intervention target: physical activity/built environment, food/beverage, messaging, or multiple. Two reviewers independently assessed the risk of bias for each study using the Effective Public Health Practice Project tool. Results Of 158 natural experiments targeting obesity, 17 reported adult weight/BMI outcomes. Four of 9 studies reporting on physical activity/built environment demonstrated reduced weight/BMI, although effect sizes were small with low strength of evidence and high risk of bias. None of the 5 studies targeting the food/beverage environment decreased weight/BMI; strength of evidence was low, and 2 studies were rated high risk of bias. Discussion We identified few natural experiments reporting on the effectiveness of programs, policies, and built-environment changes on adult obesity. Overall, we found no evidence that policies intending to promote physical activity and healthy eating had beneficial effects on weight/BMI and most studies had a high risk of bias. Limitations include few studies met our inclusion criteria; excluded studies in children and those not reporting on weight/BMI outcomes; weight/BMI reporting was very heterogeneous. More high-quality research, including natural experiments studies, is critical for informing the population-level effectiveness of obesity prevention and control initiatives in adults.