Yankovic came up with the idea for Fat while watching the Bad music video, when he had an epiphany that a parody of that song titled Fat would be a good sequel to Eat It (a previous Weird Al Michael Jackson parody). As he watched the Bad video, he imagined an obese version of himself trying to get through the turnstiles on a subway, and resolved that he would do it.
When performing in concert, Yankovic wears a fat suit and a mask that makes his face appear fat. Due to undergoing laser vision correction surgery, he no longer needs to wear glasses, though he wears glasses with non-prescription plastic lenses in order to help hold on the mask.
Directed by Jay Levey, the video for "Fat" parodies various elements of the "Bad" video by Jackson; Yankovic was able to get permission from Michael Jackson to use the same subway set from "Bad" for the video. Jackson had built an exact replica of the original set for the movie Moonwalker to be used in the segment called "Badder", and before striking it, he offered to allow Yankovic to use it. Here is a list depicting some parody elements:
The lighting in Jackson's video is much darker. Yankovic filmed his parody video with much brighter lighting, and it appears as though it was filmed in the daytime.
The video starts off with a non-musical black-and-white scene, as in the original, but the scene is shortened. We begin at the subway station where a trio of obese men played by Lou B. Washington, who later joined the cast of Al's 1989 film UHF criticized Al for not eating much unhealthy food lately. Possibly, a parody of real gangsters pressuring unsuspecting kids to try drugs. They try to get Al to eat a hamburger, a slice of pizza, and finally, a Ding Dong, which they pull out of their pockets. The original video consisted of Jackson coming back from high school and his old street friends bugging him about going to school and becoming soft.
The lines "Are you fat, or what?" and "You ain't fat, you ain't nothing!" mimicking lines in the original, only using the word "fat" instead of "bad". Then the scene changes to color.
After the non-musical black-and-white scene, the dancers can be seen goofing off. Two of them lost a high five, while another can be seen waving and mouthing the words "Hi, Mom" over and over again, and is pulled away from the camera by another of the dancers by his nose. As a whole the group looks disorganized and fidgety, as a parody of the precise choreography in Michael Jackson's video.
The song's music video consisted of Yankovic with a group of six dancers. The original video consisted of Jackson with a group of twenty dancers.
The six dancers from Jackson, which are now with Yankovic in the video are obese instead of skinny. They are also dressed similarly to the dancers in "Bad." In order to get the dancers Yankovic simply advertised for "very fat dancers" in a trade journal, and his hunch that such people might exist was soon proven right. Yankovic stated in the liner notes for Permanent Record: Al in the Box that one of the dancers was actually a pizza delivery man who delivered pizzas to the casting office. He was put in the video because he had the "perfect physique", according to Yankovic.
Instead of a troupe of dancers sliding along the ground, the video for "Fat" shows Yankovic being transformed into a fat guy. The dancers are making a shush gesture as the music starts playing.
Yankovic's black outfit looks just like Jackson's, but the buckle and zipper ornamentation is exaggerated. This is the same outfit that Jackson wore in the video.
Yankovic does Jackson's famous "crotch-grab", but with humorous sound effects added, such as a "boing" and a cowbell.
In the original video, Jackson said "Shamone, shamone, lay it on me, all right". In "Fat", Yankovic said "Ham on, ham on, ham on whole wheat, all right", and Yankovic is shown eating his food very fast.
When Yankovic tries to jump over the turnstiles on the first bridge of the song, he can't get over. Jackson, by contrast, easily jumps on then off.
In one musical interlude, Yankovic jumps on a dancer and crushes him while Jackson merely jumps on his shoulder.
In the middle-end, the dancers and Yankovic are moving in a line close together trying to go fast and slightly succeed in doing so, while in "Bad", the dancers are doing the same thing but slower and easier.
In "Bad", Jackson moves in a circle while the camera follows him. In "Fat", Yankovic moves in a circle while the camera follows him, but for much longer. Eventually, Yankovic moves too fast, and begins to fly. He grabs a hold of the tripod to not fly away, but loses his grip, and flies off with a startled cry.
When Yankovic flings his arms around, sound effects are heard. This is direct reference to the noises heard when Jackson flings his arms. Yankovic acts confused testing out the sound effect movements, and moves other parts of his body, making other sound effects. Al's dancers also appear confused.
In "Bad", Jackson and his dancers scream loudly for no reason at random times. Yankovic parodies this by having a scene where he and his dancers scream "Ho!" every now and then. One of the dancers hands Yankovic a gardening hoe, and Yankovic comments on it by saying "Hoe!" This also occurs when the song is performed live, though, occasionally, a man in a Santa Claus suit comes on stage and is belly-bumped or, as seen on "Weird Al" Yankovic Live!, punched in the face by Al. In the Straight Outta Lynwood tour, in keeping with the "gangsta" theme of the latest album, the man dressed as Santa was replaced by a man dressed as a promiscuous woman. Al points at the visitor and shouts "Ho!"
The camera follows Yankovic and the other dancers as they run through the station, when Yankovic is handed the gardening tool. And Yankovic said "Hoe!" to the dancers. After a brief pause, he and the others realize the camera is still moving, and they start to run again, moving even faster to try to get into the camera's viewpoint now yelling "Ho!" to get the camera to slow down. Eventually they disappear off-camera. Then, the camera pans back. Upon returning to where they left off it's discovered that they are now catching their breath from the running that Jackson and his troupe are able to do easily. Yankovic leans against a pillar and tilts it.
When Yankovic runs up the steps and removes the air vent cover, he spins and flourishes excessively in a parody of Jackson's dancing advance towards the vent. Also, the wind in this video is much stronger. Several dancers get blown away, and Yankovic holds up a small pinwheel-type fan, and stays standing as his dancers are blown out of sight. A chicken is seen passing by the camera.
At one point near the end, Jackson whoops three times in a row. The third time, Yankovic holds up a speech bubble containing the word, "Woo!" instead of actually singing it, satirizing the voice synchronization of Michael Jackson's video, in which several scenes are seen with Jackson mouthing words that are not heard.
Instead of dancers dancing near the end, we see the dancers bumping their stomachs, and falling into each other. In this scene, the word "FAT" is spray painted on the wall, instead of "BAD".
The wanted poster near the end is different. Instead of, "Wanted for Sacrilege", with the word "BAD" below, it reads, "Wanted for Gluttony", with the word "FAT" underneath.
The man in the roller skates walks very slowly and with much difficulty, instead of smoothly. In "Bad", one of the dancers is seen doing a version of the moonwalk where he is not moving at all.
When Jackson and his group run up the stairs nearing the end one of the dancers does a continuous amount of backflips, in "Fat" one of Al's dancers tries to do a single cartwheel and barely makes it. Although he celebrates as though this is a great success.
In "Bad", Jackson screams at the end of the video for no apparent reason. In "Fat", Yankovic screams at the end of the video: his fingers are caught in a mousetrap that seemingly came out of nowhere. The same sound effect is used for the trap as from earlier, when Yankovic was waving his arms around.
Finally, at the very end, Yankovic says "Who's fat?", while Jackson says "Who's bad?". The video freezes with a closeup shot of Yankovic holding his fist. In "Bad", it freezes with Jackson a foot away from the screen, although on the full version of the video, he sings a bit longer, as the parts are in the original song, while the parts are not in "Fat".