This paper adds to the “costs of recessions” literature by examining whether the Great Recession caused an increase in body mass index (BMI) among economically insecure working age adults. Using a difference-in-differences (DiD) design and two panels of the Canadian National Population Health Survey, we compare the pre-recession era (2004–2005) with the Great Recession (2008–2009). In addition to stratifying by gender, quantile regressions examine BMI changes at different points along the outcome distribution, and we extend our DiD model to examine how effects vary across income, education, and age. Our results suggest that the increased economic stress of job insecurity or joblessness during the Great Recession caused a 2-point increase in BMI for females, and a 3-point increase for males aged 45–64. Results weakly suggest that lower educated males who were economically insecure during the Great Recession also gained 3 BMI points. For working age Canadians of average height, this translates to a 12 and 20 lb (5.44 and 9.07 kilogram) increase for vulnerable females and males respectively.