Obesity increases risk for numerous metabolic and cardiovascular diseases, and even certain forms of cancer. Much of this increased risk is mediated by a resistance to the normal actions of insulin (i.e. insulin resistance), and related complications. Despite significant effort to develop effective pharmaceuticals to combat insulin resistance, lifestyle intervention (e.g. diet modification and increased physical activity) remains the gold-standard treatment. To this end, my research is aimed at elucidating the mechanisms underlying improved insulin sensitivity following lifestyle modification – particularly exercise activity. This work involves the study of lipids as mediators of insulin resistance and the ability of exercise to significantly enhance insulin sensitivity via altered skeletal muscle lipid metabolism. The long-term goal of this work is to develop novel and effective therapeutic intervention strategies for the treatment of insulin resistance in humans.