Lisa the Vegetarian/References

Trivia

 * This episode establishes Lisa's status as a vegetarian, an idea that was first hinted in the episode "Lisa's Wedding". One of Paul McCartney's stipulations for doing the guest spot was that Lisa's conversion to vegetarianism be a permanent one. Thus, it is an instance of continuity in the Simpsons universe that has been strictly held to.
 * When Lisa flashes back to scenes of friends and family eating meat, Kent Brockman chews a turkey leg during a newscast. The sound byte of his speech in between bites comes from his line in the "Attack of the 50 ft. Eyesores" segment of that year's "Treehouse of Horror:" ["Lock your doors,] bar your windows, [because] the next [ad you see could destroy your house and eat your family!"]

Goofs

 * Strangely, Apu attends Homer's all-meat BBQ, even though he is a revealed vegetarian at the end of the episode.
 * Didn't Clancy Wiggum and his wife inform that Ralph can't be trusted with scissors in a prior episode, yet he's entrusted with scalpels.

Cultural references

 * The pig that Homer roasts and blasts into the air, flying over the nuclear power plant, is a direct reference to the cover of the Pink Floyd album Animals, which shows a pig flying over London's Battersea Power Station.
 * I Spit on Your Grave, a notorious exploitation film, is listed on the billboard for the drive-in cinema.

Beatles references

 * Numerous references to The Beatles are present in the episode. Apu claims to have met Paul during the Maharshi period. The Beatles' visit to this guru in India was a big media story in 1967. Apu then claims to have been called "The Fifth Beatle" (mispronouncing it to rhyme with "Seattle"), a claim which Paul does not seem to agree with. The way Apu pronounces Beatles is a reference to how the antagonists in the movie Help! say it.
 * Paul McCartney asks, "She's leaving home?", referencing the song of the same title from The Beatles' Sgt. Pepper's Lonely Hearts Club Band.
 * Lisa's remark, "Wow! Paul McCartney. I learned about you in history class", is a joke about the enormous cultural importance of the Beatles.
 * When Linda McCartney says "whenever we're in Springfield, we like to spend time in Apu's garden in the shade!" paraphrasing a lyric from the song "Octopus' Garden" (from the album Abbey Road).
 * The version of "Maybe I'm Amazed" that plays over the end credits is an original mix by the Simpsons staff that, when played backwards, contains snippets of Paul McCartney reciting a recipe for lentil soup – a throwback to an earlier gag. The recited recipe in forward speed can be found on the "Extras" section on Disc 1 of The Simpsons: Complete Season 7.
 * One of the backwards snippets says "Oh, and by the way, I'm alive." - a reference to the Paul is dead conspiracy theory.