Her schoolmates and family members ridicule her for her beliefs, but with the help of Apu as well as Paul and Linda McCartney, she commits to vegetarianism.

Directed by Mark Kirkland,[1] "Lisa the Vegetarian" is the first full-length episode David S. Cohen wrote for The Simpsons.

Former Beatle Paul McCartney and his wife Linda guest-star in the episode; their condition for appearing was that Lisa would remain a vegetarian for the rest of the series.

Reaction at school is no better: when Lisa objects to dissecting a worm in class and requests a vegetarian alternative to the cafeteria food, Principal Skinner labels her an "agitator".

After her second-grade class is forced to watch a Meat Council propaganda film starring Troy McClure that criticizes a vegetarian eating style, Lisa's classmates tease and shun her.

Lisa eventually succumbs to the pressure to eat meat and bites into a hot dog from the roller grill at the Kwik-E-Mart.

However, Apu, an avid vegan, reveals that she has eaten a tofu dog, and leads Lisa through a secret passageway to the Kwik-E-Mart roof, where they meet Paul and Linda McCartney.

On her way home, Lisa reunites with Homer, who is frantically searching for her, and apologizes to her, admitting that he and Bart went too far in picking on her for wanting to be a vegetarian.

[5] George Meyer, a writer known among the staff for his "bizarre physical jokes",[6] contributed the idea of the barbecue pig getting caught in the spillway and flying into the air.

[6] Cohen credits writer John Swartzwelder for inspiring the scene in which Homer finds it impossible to believe that bacon, ham, and pork chops could possibly come from the same animal.

John Lennon was murdered before the show was created, but Ringo Starr and George Harrison had guest-starred in 1991 ("Brush with Greatness") and 1993 ("Homer's Barbershop Quartet"), respectively.

[6] McCartney agreed to appear, but requested that Lisa remain a vegetarian for the rest of the series rather than revert to meat-eating in the next episode.

Mirkin enjoyed the joke enough to reuse parts of it in "Lisa the Vegetarian", adding new twists to further enhance the comedic effect.

[6] For instance, McCartney tells Lisa that playing his 1970 song "Maybe I'm Amazed" backwards will reveal "a recipe for a really rippin' lentil soup".

Pepper's Lonely Hearts Club Band",[5] to which the McCartneys snap along, and Lisa backs away slowly while cringing to Apu's off-key rendition.

[35] "Lisa the Vegetarian" has received widespread acclaim from television critics and is popular among the staff of The Simpsons; among them, Mirkin,[6] Kirkland,[25] Groening,[15] and writer Ian Maxtone-Graham list it as one of their favorite episodes.

[36] In the DVD audio commentary for the episode, Mirkin called the opening sequence at the petting zoo one of his favorite set pieces in the show's history.

[37] The Ventura County Reporter's Matthew Singer thought it was "overflowing with great individual scenes", particularly Troy McClure's Meat Council propaganda video, which he said "may be the funniest isolated segment in the history of the show".

[38] Today's Patrick Enwright, who listed the episode as his second favorite of the series, highlighted the "You don't win friends with salad!"

Todd Gilchrist of IGN said he thinks the key to The Simpsons' longevity is its "sentimental but not gooey" approach to storytelling and character development.

But rather than simply punctuating the episode with an iconic image of the porker soaring through the air, the writers actually develop a story into which the joke fits.

"[40] The Niagara Gazette's Phil Dzikiy said that "the character development and storytelling is perfect", noting that the episode was "equally hilarious, touching and satirical".

Warren Martyn and Adrian Wood, the authors of the book I Can't Believe It's a Bigger and Better Updated Unofficial Simpsons Guide, called it a "superb" performance.