Effects of environmental exposures on weight-related health behaviors and outcomes

The US obesity rate has increased alongside an increase in extreme weather events, such as heatwaves, which may influence an individual's desired bodyweight, dietary habits, and level of physical activity. In this paper, we provide evidence on the role of environmental exposures in shaping weight-related health behaviors and outcomes. Using data from the Behavioral Risk Factor Surveillance System and an identification strategy leveraging temperature deviations from local seasonal norms, we show that adults were less likely to report trying to lose weight, dieting to lose weight, and exercising to lose weight when temperatures fell below 20–25 °C (68–77 °F). We then show that temperature increases were associated with increases in respondents' weekly servings of fruits and vegetables and the number of minutes they spent engaged in moderate or vigorous physical activity. Despite these behavioral changes, we find no evidence of a relationship between temperature and BMI. Therefore, despite concerns that rising global temperatures may increase the prevalence of overweight and obesity, our findings suggest that it is in fact cooler days that reduce the likelihood individuals engage in weight management behaviors.