"Lisa the Vegetarian" is the fifth episode of the seventh season of the animated series The Simpsons, originally aired on the Fox network in the United States on October 15, 1995. In the episode, Lisa Simpson stops eating meat after a trip to a petting zoo. Initially ridiculed by her family and friends for her decision, she commits to vegetarianism after advice from Apu and from Paul and Linda McCartney. The McCartneys guest-starred as themselves, appearing on condition that Lisa would remain a vegetarian for the rest of the series. The episode contains references to Paul's musical career, and his song "Maybe I'm Amazed" plays over the closing credits. Directed by Mark Kirkland, "Lisa the Vegetarian" is the first full episode of The Simpsons written by David X. Cohen. It was watched by 14.6 million viewers and received positive reviews from television critics. For its themes on animal issues, it won an Environmental Media Award and a Genesis Award.