Economic insecurity is a common term in popular discourse and the focus of much, if not most, social policy, but uninsurable, unavoidable downside risk fits poorly with neo-classical economics. Defined as: “the anxiety produced by a lack of economic safety, i.e. by an inability to obtain protection against subjectively significant potential economic losses.”, it is worth studying because (1) measurement of economic (in)security should be part of measurement of economic well-being; (2) individuals insure and/or change behaviour to mitigate costs of uninsurable hazards; (3) economic security has been defined as a basic human right and (4) the nativism of the economically insecure has important political economy implications in contemporary societies. This seminar focusses on the implications of economic insecurity for individual mental health and obesity. After discussing the importance of economic insecurity for the Index of Economic Well-Being, it surveys a series of papers which use panel data and the natural experiments, individual fixed effects, Diff-in-Diff econometric methodology to find a causal role for greater economic insecurity in: (1) obesity prevalence due to Unemployment Insurance cuts in Canada in the 1990s; (2) mental and physical health in Australia in the 2000s and (3) child obesity in families affected by the end of the Iron Rice Bowl in China, due to State Owned Enterprise reform. Notably, adverse health impacts are heavily gendered, larger for the less educated but important for all but the most affluent, experienced both by adults who actually suffer income losses and whose probability of loss increases and by children in affected families and somewhat mitigated by social insurance payments.