Dean Ornish, MD, was a founder of the Preventative Medicine Research Institute in California and was considered revolutionary in the early ’90s when he suggested that a basically vegetarian diet can reverse symptoms of heart disease and published The Ornish Spectrum Diet based on 35 years of research.  He ranks foods from healthiest ("Group 1") to the most indulgent ("Group 5").   In general, the more you stick with foods toward the Group 1 end of the spectrum, the more benefits you'll reap in terms of weight loss and overall health.  In addition to strong recommendations for exercise, stress management with yoga and meditation and eating smaller meals, this diet emphasizes

• Eating all the beans, legumes, fruits, grains, and vegetables needed to feel full.
• Using low- or nonfat dairy products such as milk, cheese, and yogurt in moderation.  Only 10% of calories should come from fat.
• Meats (both red and white) should be avoided along with oils and products containing oils, including avocados, olives, nuts, seeds, full-fat dairy, and sugar.