When the thermometer rises, the scales tip: Extreme temperature exposure and obesity

Obesity is a global public health issue, with over 1.9 billion adults reported to be either overweight or obese. Despite the high financial and health costs associated with obesity, the global prevalence of obesity across all age groups has been on the rise. Using the Household, Income and Labour Dynamics in Australia (HILDA) Survey, we provide evidence of the causal relationship between extreme temperature exposure and obesity. We show that there is a positive association between high temperatures (above 30°C) and obesity. Specifically, an additional day of exposure to temperatures above 30°C in a year is associated with a 0.02 percent increase in BMI and a 0.2 percent increase in the probability of being obese. We find these effects to be pronounced for older cohorts, and robust to alternative specifications and falsification of our extreme temperature exposure measure. We provide evidence that the underlying mechanisms for our baseline relationship are reduced physical activities and low internal locus of control due to extreme temperature exposure.