Cohen, PhD, RD, a professor emerita at the University of Massachusetts in Amherst. 'This diet is rich in fruits and vegetables, whole grains, seafood, nuts and legumes, and olive oil,' says Nancy L. It’s a diet known for being heart-healthy. You’ll find that in their meals, Mediterranean dieters emphasize a plant-based eating approach loaded with vegetables and healthy fats, including olive oil and omega-3 fatty acids from fish.