Best Plant-Based Diets. Plant-based diets are good for the environment, your heart, your weight and your overall health. U.S. News defines plant-based as an approach that emphasizes minimally processed foods from plants, with modest amounts of fish, lean meat and low-fat dairy, and red meat only sparingly. The experts who rated the 11 diets below put the Mediterranean diet at the top of the list. Among the qualities considered were each diet’s ability to deliver weight loss, provide good nutrition and safety, and be relatively easy to follow.