The Effects of COVID-19 Lockdown on Bodyweight Status and Lifestyle Behaviors Among US Adults: Evidence from the Behavioral Risk Factor Surveillance System 2018-2020

The COVID-19 pandemic has impacted the lives of individuals living in the U.S. in a variety of ways. The combination of various effects caused by the pandemic and social distancing measures (SDMs) are likely to jointly determine individual health outcomes like body weight during the pandemic. In this paper, we use data from the 2018-2020 waves of the Behavioral Risk Factor Surveillance System (BRFSS) to estimate the COVID-19 pandemic’s effect on Body Mass Index (BMI) and the probability of obesity among adults living in the U.S. We use the introduction of initial COVID-19 lockdown as an indicator of when individuals’ lifestyles were likely changed by the pandemic, controlling for indicators of the economy reopening post-initial-lockdown, the contemporaneous presence of other social distancing measures, and the state COVID-19 cases per 1000 individuals. We estimate the overall effects of interest within a difference-in-differences (DID) framework, relying on the plausibly exogenous timing of COVID-19 lockdown initiation. We find a statistically significant association between the COVID-19 lockdown and body weight, with the initial lockdown leading to a 0.18 unit increase in BMI and 1.4 percentage point increase in the probability of obesity. Results for an event study suggest that adults experienced a temporary decrease in body weight in the first month of lockdown, then an increase in body weight as the time since lockdown progressed. Our findings are robust to a variety of sensitivity analysis and falsification tests. We find that COVID-19 lockdown’s effects on body weight was larger and more stable among men, non-white adults, individuals with lower levels of educational attainment, and adults living in more densely populated states. Analyzing the potential mechanisms driving our effects, while we did not find significant effects of COVID-19 on BRFSS-defined variables such as physical activity and mentally unhealthy days, we find that COVID-19 potentially impacted adult diets with increases in Google search intensity for the terms of food delivery and some specific high calorie foods. Similarly, we find that individuals may have engaged in more sedentary behaviors during the pandemic as implied by increased Google search intensity for most major video streaming platforms. Our study provides valuable results for researchers, policy makers, and other interested stakeholders concerned with the pandemic’s potential impacts on body weight.