A vegetarian diet supplies the most antioxidants, fiber, vitamins and minerals with the least amount of calories. Those brightly colored foods have a bonus added to this - they fight disease! They are abundant in health-giving nutrients.
Are you worried about Protein? Don't need to. It can be obtained from many sources that do not bring disease. Peas, beans, nuts, whole grains, even some vegetables contain protein. A diet high in meat and animal fats stimulates atherosclerosis that leads to heart disease. We must not forget that large quantities of protein overload the kidneys and can produce disease.
Furthermore I highly recommend you to watch the "Forks over knives" documentary. There is a high chance it will challenge your view on health and diet!