Becoming a vegetarian.  Avoiding meat is only one part of the picture.  A healthy vegetarian diet should be chock-full of foods with known benefits.
D002318:Cardiovascular Diseases / Q000517:prevention & control; D003924:Diabetes Mellitus, Type 2 / Q000517:prevention & control; D014676:Diet, Vegetarian; D019587:Dietary Supplements; D005247:Feeding Behavior; D007722:Health Knowledge, Attitudes, Practice; D006304:Health Status; D006801:Humans; D009369:Neoplasms / Q000517:prevention & control