PPARδ stimulation or over-expression in adipocytes leads to increased fatty acid oxidation, improved exercise tolerance, and resistance to obesity. GW 501516 is the first highly selective synthetic PPARδ agonist available. GW 501516 binds to human PPARδ with an IC50 value of 1 nM, and is at least 100-fold selective for PPARδ compared to PPARα and PPARγ. In obese primates, GW 501516 increases high density lipoprotein cholesterol and apolipoprotein A-1 specific reverse cholesterol transport. GW 501516 is therefore a model compound for a new type of obesity therapeutic, as well as a selective pharmacological tool for understanding lipid metabolism.