A 77-year-old woman presented with unstable angina and had severe three-vessel coronary artery disease, but declined coronary bypass graft surgery. Instead, she chose to adopt a whole-food plant-based diet, which consisted of vegetables, fruits, whole grains, potatoes, beans, legumes and nuts, in addition to medical therapy. Her symptoms and exercise capacity improved rapidly. Several months later, she resumed a Western diet. Her angina returned and she underwent coronary bypass graft surgery. Plant-based diets have been associated with a reduction of plasma lipids, improvement of diabetes control, reduced weight, regression of atherosclerotic cardiovascular disease and increased survival, while consuming animal products including meat, dairy and eggs has been associated with worsened cardiovascular risk factors, clinical cardiovascular endpoints and increased mortality. Adoption of a whole-food plant-based diet and a reduction of animal product consumption should be among the first recommendations for patients with atherosclerotic cardiovascular disease.