Vegetarianism means the avoidance of animal products such as meat, fish, and chicken. It may or may not include other animal derivatives; some vegetarians consume dairy products and eggs while others do not. Vegetarianism is a practice adopted because of many different reasons. Religion and health are the two most common reasons people turn to vegetarianism; however, many important historical figures have been vegetarians due to ethics or environmental concerns.
Pythagoras is one of the earliest documented vegetarians. In the sixth century BC, he cited ethical grounds as his reasons for becoming a vegetarian. He is often quoted as saying "As long as Man continues to be the ruthless destroyer of lower living beings he will never know health or peace." Many famous scientists were also vegetarian, including Charles Darwin, Thomas Edison, Albert Einstein, Sir Isaac Newton, and Benjamin Franklin. All of them were also ardent defenders of animal rights. In fact, all of them wrote extensively about the importance of being a vegetarian.
Many present-time artists are also vegetarians. Fiona Apple has been a vegetarian for over a decade, while Christina Applegate and Pamela Anderson became vegetarians after joining forces with the PETA Foundation (People for the Ethical Treatment of Animals). In fact, many actors and actresses that are vegetarians have been somehow associated with animal protection agencies. Paul McCartney and his late wife Linda were involved in numerous animal charities, while Doris Day runs the Doris Day Animal League. Brigitte Bardot, the French sex symbol, produced a series of documentaries in the 1980s, with one episode completely dedicated to the issue of being a vegetarian.
Many famous people define themselves as "mostly vegetarians," which means they only occasionally eat meat. This is the case of Orlando Bloom, who was a vegetarian but went back to eating meat while filming Lord of the Rings. The same is true of Drew Barrymore, David Duchovny, and Demi Moore. People who are occasional vegetarians usually follow the diet because of health reasons rather than ethical ones.
Despite popular belief, many world-class athletes are also vegetarians. This includes bodybuilder Andreas Cahling, Olympic wrestling medalist Chris Campbell, WBC World Middleweight Champion Keith Holmes, and tennis champion Billie Jean King.