 He has said his main reason for becoming vegetarian was health concerns, including avoiding parasites and heart disease, and he emphasizes the environmental benefits of vegetarianism.His transition was made easier because he had eaten little meat for aesthetic reasons as a child, and he readily adopted his wife's vegetarianism because she does much of the cooking in their household.Speaking in 1990, he said that with the increasing availability of meat substitutes, "It might take 20 years.