Kathy Fariello loves Italian food, from fried meat balls to pizza rustica with ham and salami, and her favorite, mozzarella cheese wrapped in prosciutto.

But when the 69-year-old widow, who suffers from coronary artery disease, joined a clinical trial sponsored by NYU Langone Health to test a vegan diet on heart patients, she had to say ciao to all these dishes.

In came the kidney beans and dairy-free imitation cheese.

Out went the mozzarella and cold cuts. “All of that, forget about it,” says Mrs. Fariello, who lives on Staten Island in New York City. Yet she was determined to follow the diet, convinced it could save her. “I have four beautiful grandchildren, I will do whatever I have to do,” says Mrs. Fariello, who had a heart attack a couple of years ago.