 " Lisa the Vegetarian " is the fifth episode of the seventh season of the American television series The Simpsons . It originally aired on the Fox network in the United States on October 15 , 1995 . In the episode , Lisa decides to stop eating meat after bonding with a lamb at a petting zoo . Her schoolmates and family members ridicule her for her beliefs , but with the help of Apu , Paul , and Linda McCartney , she commits to vegetarianism . 
