Background/Aims: Prior to the introduction of statins, the most salient intervention for lowering cholesterol and preventing cardiovascular disease involved changes in lifestyle behaviors (such as diet and exercise). This study investigates whether statin drugs diminish incentives for healthy lifestyle behaviors and lead to worsened diets and/or lower levels of exercise. Although statins are highly effective in reducing cardiovascular disease risk, lifestyle improvements can garner significant health benefits in addition to lowering cholesterol. Methods: An empirical investigation is conducted through a causal inference analysis of the introduction of statins on diet and exercise behaviors. The conceptual framework is derived from a dynamic economic model based on human capital and decision theory. A detailed longitudinal survey on health behaviors administered to a panel of 8,000 individuals from a Minnesota-based HMO is linked with statin prescription (claims) data for the analysis. Key to causal inference, the timing of this survey corresponds with rapid secular trends in statin adoption. The corresponding significant intrapersonal heterogeneity in observed treatment (i.e., statin use) allows for several analytical identification strategies to correct for endogeneity bias—including fixed effects, Hausman-Taylor, and (physician/clinic-based) instrumental variable methods—and improves the robustness of results. Outcome measures include likelihood of engaging in regular exercise, intensity of physical activity, eating fewer calories or less fat to lose weight, level of fruit and vegetable consumption, and frequency of between-meal snacking on candy and other sweets. Results: Preliminary results show an effect that is ostensibly counter-intuitive: a new statin prescription tends to improve health behaviors. However, this result can be reconciled—particularly, in the short-run—as a signaling response induced by the need for a pharmaceutical intervention. The study design limits inference to short-run impacts, but a cardiovascular disease simulation model is used to quantify the health and cost-impact on the U.S. population under various long-run scenarios. Conclusions: Rather than competing with healthy lifestyle behaviors, statin drugs appear to generally complement lifestyle improvements—at least in the short-term. However, behavioral theory suggests further empirical investigation on long-term effects is warranted.