Katherine Tucker, a professor of nutritional epidemiology at Northeastern University in Boston, said it’s possible that the low-fat Ornish plan might be more beneficial for those with heart disease. “People who have had heart attacks might have a genetic predisposition to having more damaging effects on their arteries from higher fat diets,” she said, but more research is needed to confirm this.

She recommends following the Mediterranean diet for heart disease prevention, however, because it’s easier for most people to stick with permanently.