"Weight Gain 4000" is the 3rd episode of Season One, and the 3rd overall episode of South Park. It originally aired on August 27, 1997. This was the second episode produced and the third to air in the series.
Cartman wins the "Save Our Fragile Planet" essay contest and it is announced that Kathie Lee Gifford will be coming to South Park to present him with the award. This enrages Wendy, who believes Cartman cheated.
The town becomes a flurry of excitement as everyone prepares for Kathie Lee to arrive, including Mayor McDaniels, by organizing a large-scale event to highlight the town and further her career. Chef is asked to sing at the event and hopes this will enable him to have sex with Kathie Lee. (He is eventually successful).
Meanwhile, the children are asked to set up an Indian play in honor of Kathie Lee (which turns out to be completely violent) with Mr. Garrison as the director. However, Mr. Garrison has a long-standing grudge against Kathie Lee for upstaging him and Mr. Hat with a rendition of "If They Could See Me Now" during a national talent show when they were children. Mr. Hat tries to get Mr. Garrison to kill Kathie Lee, but Garrison initially refuses and tries to get on with the play, which turns out to be historically accurate but also extremely violent since the Pioneers and the Indians started to fight at the beginning of the play. The townspeople are outraged when they see a rehearsal of the play (as it is extremely violent even resulting in a fatality). Mayor McDaniels tells Mr. Garrison that Kathie Lee wouldn't like the play, to which Mr. Garrison responds "To hell with Kathie Lee Gifford!" shocking the towns people. Mr. Garrison is fired as the director. As a result, he agrees to let Mr. Hat carry out the murder.
While the town gears up for the Kathie Lee's visit, the Mayor tells Cartman that he needs to get in shape for Kathie Lee's visit. After he sees a commercial for Weight Gain 4000, a body building supplement and thinks he should use it to bulk up for the big day, so he purchases some. Cartman fails to note (or in his case refuses to note) that exercise must coincide with the consumption of the product in order to attain the desired results. Consequently, he suffers an exponential weight gain. While Cartman elevates his obesity to the next level, Mr. Garrison visits Jimbo Kern's gun store to purchase a rifle, with which he plans to kill Kathie Lee.
That night, Wendy discovers Mr. Garrison's plan while sifting through the essays in his files to confirm that Cartman cheated. As it turns out, Cartman simply procured a copy of Walden by Henry David Thoreau and wrote his name on it.
Kathie Lee arrives in a bubble of bulletproof glass the following day, and as she gets to the presentation stage, Chef sings an extremely graphic song about his desire to make "sweet love" to her. Wendy and Stan try to stop Mr. Garrison when he goes to the book depository to attempt assassination, and Wendy manages to talk Mr. Garrison down, but Stan messes things up by asking about how Kathie Lee upstaged him at the talent show contest, which causes Mr. Hat to take the shot anyway. At the same time, the stage collapses under Cartman's weight, throwing Kathie Lee to safety and moving Kenny into Mr. Hat's line of fire. The bullet hits Kenny and sends him flying into a flagpole, resulting in him being impaled in the head. Kathie Lee's security men then drive her out of South Park and away from the gunman, and Wendy tries to explain how Cartman cheated on the essay, but the townspeople really only cared about Kathie Lee and leave bummed.
The episode ends with Mr. Garrison in the mental hospital (with Mr. Hat in a straight jacket) and Cartman appearing on Geraldo because of his morbid obesity, where he comically states "Follow your dreams. You can reach your goals, I'm living proof... Beefcake, Beefcake!" Also, Chef succeeds in his goal of fornicating with Kathie Lee, although even he is somewhat taken aback by her sexual demands asking if she is trying to kill him.