Dr. Grundy's major research area is in cholesterol and lipoprotein metabolism. He has published over 300 original papers, and numerous solicited articles and chapters. Notable research accomplishments include the development of methods for measuring cholesterol balance and biliary lipid secretion in humans, identifying the metabolic causes of cholesterol gallstones, defining effects of saturated and unsaturated fats, especially monounsaturated fatty acids, on cholesterol and lipoprotein metabolism, uncovering genetic defects underlying hypercholesterolemia and other forms of dyslipidemia, identifying metabolic defects in hypercholesterolemia, hypertriglyceridemia, hypoalphalipoproteinemia, and defining mechanisms of action of several lipid-lowering drugs, notably fibrates and HMG CoA reductase inhibitors (statins).