Obesity is a heterogeneous group of disorders in terms of etiology; time of development; adipose tissue characteristics; metabolic abnormalities; and associated morbidity and mortality from coronary disease. The typical patient at risk for coronary artery disease in middle age develops abdominal obesity with hypertrophic fat cells in young adulthood, has hypertension, hyperglycemia, hypertriglyceridemia, hypercholesterolemia, and decreased high density lipoprotein (HDL)-cholesterol levels. Two common genetic metabolic disorders--noninsulin-dependent diabetes and familial combined hyperlipidemia--both conform to the prototype, accounting perhaps for a substantial amount of the coronary artery disease associated with obesity.