The present invention is directed at substituted heteroaryl- and phenylsulfamoyl compounds, pharmaceutical compositions containing such compounds and the use of such compounds as peroxisome proliferator activator receptor (PPAR) agonists. PPAR alpha activators, pharmaceutical compositions containing such compounds and the use of such compounds to elevate certain plasma lipid levels, including high density lipoprotein-cholesterol and to lower certain other plasma lipid levels, such as LDL-cholesterol and triglycerides and accordingly to treat diseases which are exacerbated by low levels of HDL cholesterol and/or high levels of LDL-cholesterol and triglycerides, such as atherosclerosis and cardiovascular diseases, in mammals, including humans. The compounds are also useful for the treatment of negative energy balance (NEB) and associated diseases in ruminants.