BACKGROUND Animal experiments and epidemiological studies have suggested that coronary disease could be prevented, arrested, or even reversed by maintaining total serum cholesterol levels below 150 mg/dL (3.88 mmol/L). In 1985, we began to study how effective one physician could be in helping patients achieve this cholesterol level and what the associated effect of achieving and maintaining this cholesterol level has on coronary disease. METHODS The study included 22 patients with angiographically documented, severe coronary artery disease that was not immediately life threatening. These patients took cholesterol-lowering drugs and followed a diet that derived no more than 10% of its calories from fat. Disease progression was measured by coronary angiography and quantified with the percent diameter stenosis and minimal lumen diameter methods. Serum cholesterol was measured biweekly for 5 years and monthly thereafter. RESULTS Of the 22 participants, 5 dropped out within 2 years, and 17 maintained the diet, 11 of whom completed a mean of 5.5 years of follow-up. All 11 of these participants reduced their cholesterol level from a mean baseline of 246 mg/dL (6.36 mmol/L) to below 150 mg/dL (3.88 mmol/L). Lesion analysis by percent stenosis showed that of 25 lesions, 11 regressed and 14 remained stable. Mean arterial stenosis decreased from 53.4% to 46.2% (estimated decrease = 7%; 95% confidence interval [CI], 3.3 to 10.7, P < .05). Analysis by minimal lumen diameter of 25 lesions found that 6 regressed, 14 remained stable, and 5 progressed. Mean lumen diameter increased from 1.3 mm to 1.4 mm (estimated increase = 0.08 mm; 95% CI, -0.06 to 0.22, P = NS). Disease was clinically arrested in all 11 participants, and none had new infarctions. Among the 11 remaining patients after 10 years, six continued the diet and had no further coronary events, whereas the five dropouts who resumed their prestudy diet reported 10 coronary events. CONCLUSIONS A physician can influence patients in the decision to adopt a very low-fat diet that, combined with lipid-lowering drugs, can reduce cholesterol levels to below 150 mg/dL and uniformly result in the arrest or reversal of coronary artery disease.