Best Friend is a common sidekick to The Protagonist. There are three variants of this trope:
The Big Fun, brash character. This character is usually the jokester, and more extroverted compared to the protagonist. While the protagonist is uptight and tactful, the fat friend is funny and/or confrontational. They know that they're fat and they don't care about losing weight and will throw their weight around, so to speak.
They can also have some qualities to the Shrinking Violet. They know they're fat and it's one of their biggest insecurities. They are shy, awkward and generally have low-self esteem. Cue the protagonist being their ego booster, letting them know they're special and valued, and they're beautiful/handsome. In contrast to Type A, the protagonist is highlit as a caring, non-judgmental character.
In comedic works, they can also be The Ditz/Cloud Cuckoolander type. This type can be profoundly stupid or simply airheaded as it can hence the Fat Idiot title or are just plain weird otherwise. They can have some Type A traits, particularly being extroverted. They always speak slowly or walk slowly, as they can also provide comic relief from a ponderous element they exhibit as well.
What makes this different from most of the other Fat tropes is that this character is always a Satellite Character and we rarely see things from their perspectives. They're there to enhance the protagonist's traits and to simply be a friend. A possible reason for this trope's existence is a desire to be more realistic and less discriminatory by showing that not everybody in the world has a generically attractive body shape (therefore avoiding Hollywood Pudgy, perhaps), but still avoid having a fat main character.
- Ganke is the best friend of the new Ultimate Spider-Man, and he's more intelligent and extroverted than Miles.
- Though he has some Cloud Cuckoo Lander tendencies, like going to the seedy part of town to buy some collectible Lego and nearly getting killed.
- Tubby from Little Lulu would be a Type A, as he mostly tries to play pranks on Lulu. Despite this, he is a good friend to Lulu.
- Wonder Woman has Etta Candy, who was originally introduced as an outgoing prankster and boisterous sidekick during the 1940s. She became more a Type B in the Silver Age, but was mostly restored an outgoing personality in Wonder Woman (1987), where she is Wonder Woman's best friend and Steve Trevor's new Love Interest, and has come fully back to her boisterous self in Wonder Woman (Rebirth).
- The Crowd: Played with. Fat, jolly Bert seems like the prototypical jolly Type A sidekick to handsome protagonist John. However, it eventually becomes clear that John is a loser and a failure in life. Meanwhile, Bert actually works hard at his job and winds up far more successful than John does.
- Mare Nostrum: Handsome, square-jawed sea captain and protagonist Ulysses has as his first mate the jolly, spherical-shaped Caragol. Caragol is the only crewman who goes with Ulysses when he joins the French Navy along with his ship during World War I.
- In The Sorcerer's Apprentice, Dave is shown to have two different best friends at different times in his life - the first in the prologue from his childhood, the second in the 'present day' - and both of them are fat. Though they barely even count as minor characters, the second turns up long enough to seem to be a Type A. As an added bonus, he is also black.
- Tiny Cooper in Will Grayson, Will Grayson
- Zane starts out in Dinoverse as this to popular Will. It's actually a calculated relationship - Zane comes up with plans and pranks that can be attributed to Will, and Will can protect him from bullies, making himself look better still.
- Bree in the Viridian Saga is a popular theater student who seems to be eating in every scene, compared to her rather plain friend Andi. Also, her full name, Bridget Fifan, is an anagram of "fat best friend". Actually a parody of this trope.
- Fun Jungle: Xavier Gonzalez is probably the second-fattest member of the regular cast, and one of the first and most reliable friends that Teddy makes.
- Larry Mondello, Beaver's best friend during the first three seasons of Leave It to Beaver.
- Piper, the best friend of Anna on short-lived TeenNick series, Gigantic.
- Kim Parker, Moesha's best friend. She later broke out the mold and got her very own show.
- Mo Maskour from Degrassi, along with Bruce the Moose.
- Ivy from Good Luck Charlie.
- Trish from Austin & Ally.
- Eddie from That's So Raven, though his weight doesn't come up at all really.
- Noah's Arc: Alex, one of Noahs 4 main friends and the loud, fun, outspoken and confrontational one of the group.
- Liv is this to Marnie in Mustangs FC. Liv knows that she is overweight, doesn't care, and goes out of her way to enjoy life. She is generally more levelheaded than Marnie as well.
- The Big Friends Forever described in "B.F.F.!" by The Aquabats! are said to be jolly, and to help the protagonist walk through fights.
- A famous example, perhaps the Trope Codifier for western culture, is John Falstaff from Shakespeare's Henry IV, Part 1 and Henry IV, Part 2, where he is the best friend of Prince Hal. At one point, Hal amicably refers to his friend as "this bed-presser, this horseback-breaker, this huge hill of flesh..."
- Gee from Kulipari: An Army of Frogs. He prefers eating over fightinig and is one of the show's main source of comic relief, but he's a very loyal friend to Darel, and when the situation calls for it, he does take certain events seriously.
- Heffer from Rocko's Modern Life. He loves to eat, is brash and annoying, but he is a good friend to Rocko.
- LeShawna from Total Drama is this to Gwen.
- Toby is this to Jim in Trollhunters.
- In The Familiar of Zero, Malicorne is this to resident Bishōnen Guiche. He has a huge appetite and has a hard time getting dates until he falls for Irukukwu.
- Slam Dunk: Mikio Kawata.
- Franklin "Foggy" Nelson, Matt Murdock's best friend and law partner in Daredevil.
- Plutona: Diane is one to Mie, but without the expected returned respect from Mie. Diane's just trying to orbit someone cool and Mie's happy for the attention.
- Gaz's best friend, Dave, in The Full Monty is a tubby bastard and he hates it. He's always trying to lose weight and he feels so bad about it he can't even get it up for his wife. Of course Gaz pushes him into stripping to earn a bit of cash; nothing can go wrong there.
- Julie, the titular character's best friend in Lady Bird, is very shy and is insecure about her weight.
- Samwell Tarly in A Song of Ice and Fire is a good friend of hero Jon Snow and is a very extreme Type B, having terrible self esteem due to being constantly demeaned by his abusive father. Jon and others have tried to make him feel better about himself but it hasn't really taken yet.
- Terri Macgregor from Degrassi. She is friend to both the Alpha Bitch and Lovable Alpha Bitch in the show and their personalities just completely dominate hers. She's shy and withdrawn and thinks she could never get a boyfriend, until a cute boy named Rick came along who then proceeded to be an abusive prick who would later place her into a coma...
- Game of Thrones: As in the books on which it is based, Samwell Tarly is a Shrinking Violet with terrible self-esteem issues due to his abusive upbringing.
- Daredevil (2015): Foggy Nelson is pudgy compared to the very athletic Matt. He is self aware of this, and thinks this might be the reason why Matt is so good at wooing girls in spite of being blind.
- Hyung Suk, The Protagonist of Lookism is fat every 12 hours, and is very insecure because of bullying and harassment he has experienced due to it. He has two best friends in this form, Duk Hwa who's one himself (a mix of A and B) and Ji Ho, a thin guy with no muscle. He eventually also becomes best friends with Jae Yeol who in turn might be his Gay Best Friend.
- Westeros: An American Musical: Among Jon Snow's Night's Watch colleagues, Sam is the one to whom he's shown to be the closest. In "First Watch", Jon is seen encouraging Sam to not let Pyp and Grenn use him as a Butt-Monkey because of his Soldiers at the Rear position.
- The whole trope is inverted with King of the Hill, with fat kid Bobby and his satellite friend, Joseph. Joseph is especially awkward around girls as opposed to Bobby. Bill is a example played straight.
- Max's friend PJ from Goof Troop and A Goofy Movie is painfully shy and unassertive, primarily for reasons other than his weight (though as he points out in the second movie, it doesn't help). However, when he's alone with Max or after his Character Development in An Extremely Goofy Movie, he can engage in occasional confident behavior. Though Max is highlit as non-judgmental most of the time, caring is... harder to say—Max Zig-Zags No Sympathy with PJ.
- Leonard from Teacher's Pet. He is bullied, has no friends other than his best friend, Spot/Scott, and hated at school and is humiliated by his teacher who is his mother. He wants to be normal and is shy around Leslie who he loves. He also can't talk around Leslie. He dislikes being called "tubby" due to the fact he is fat and he goes psycho when he is called this.
- Under Western Stars: Smiley Burnett was the chubby comic relief sidekick to handsome, purehearted protagonist Roy Rogers in this and many other B-Movie Westerns. In this film he does stuff like getting treed by hunting dogs after he rescues a fox from a fox hunt.
- Seth from American History X is the obese, brash and stupid "best friend" of thin, muscular and charismatic protagonist Derek. During his time as a Neo-Nazi Derek somewhat reluctantly keeps Seth around, however after his transformation in jail he tries to distance himself from Seth until he finally betrays their cause.
- Rowley from Diary of a Wimpy Kid.
- Ruprecht, Skippy's best friend in Skippy Dies is a highly eccentric Teen Genius Mad Scientist. He starts off as mainly nerdy and out of touch with social trends, but becomes increasingly obsessed with the speculative and supernatural as the book progresses, and especially after Skippy's death.
- Gibby from iCarly, who is so completely eccentric and odd that it dazzles the rest of the cast.
- Lorelai's best friend Sookie from Gilmore Girls, who is a lovable, a bit scatterbrained Cute Clumsy Girl.
- Woody from The Suite Life of Zack and Cody is mostly a Type C, with elements of Type A.
- Patrick Star, from Spongebob Squarepants.
- Heffer Wolfe from Rocko's Modern Life qualifies as this type as well.
- Juicy, Calvin's slow witted friend on The PJs.
- Barry, Steve's school friend in American Dad! is a Type C with shades of Type B. Granted his Kindhearted Simpleton persona is actually the result of some prescribed vitamins that mellow his personality, unknown to him, he is actually a ruthless conniving sociopath without them.
- Stimpy acts as a Type C with elements of Type B to Ren in The Ren & Stimpy Show, being compassionate and dim witted in comparison to the smart yet manic Ren.
- Tiger, Fievel's friend from An American Tail. How dim-witted he is depends on the writer. He's mostly just a Lovable Coward.
- Mikey on Recess, though he's more naive and a bit of a Cloudcuckoolander than stupid.
- Neil from ParaNorman is the indefatigable red oni to Norman's blue oni.
Neil: "Don't blow this for me, Mitch. Besides, Norman's not weird. He just talks to dead people."
- Soos from Gravity Falls is this to Dipper and Mabel.
- Sadie from Total Drama is this to Katie. Though she has more screentime than the latter, her label is "The Sweet Girl's Friend".
- Gunther Magnusson from Kick Buttowski.
Anime and Manga
- Kurita of Eyeshield 21 is a mix of all three. He's a lot friendlier then Hiruma, but also a lot less confrontational. He's also a bit of an airhead, but then again, about half of the team is too.
- Nikaidou, Rei's self-proclaimed rival from March Comes in Like a Lion, is boisterous and outgoing (Type A) but also a bit eccentric (type C).
- Tomohiro from A Silent Voice is a combination of all three. He's more energetic and extroverted than Shoya—acting as a foil to his buddy's angsty self-hatred—but he acts weird and awkward around most other people, and has no other friends until Shoya's old frenemies start reappearing. Most of the Comic Relief in this otherwise heavy series comes from Tomohiro's wackiness. His weight never really gets mentioned, but he's clearly the chubbiest character.
- Samwise Gamgee to Frodo Baggins in The Lord of the Rings, where he's a mix between Types A and B. Gollum even refers to him as the 'stupid fat Hobbit'. More apparent here than in the books because all Hobbits there are generally portly. In the films, however, Sam is the only portly Hobbit in the Fellowship while the rest of them are (somewhat) slender.
- Ned in Spider-Man: Homecoming is a cross between Types A and C.
- Chet Morton is the best friend of The Hardy Boys, and has been described as fat, plump, chubby, stout, heavy-set, etc. He has a huge appetite, and vacillates between types A, B and C as the plot dictates.
- Duk Hwa in Lookism manages to be a mix of A and B, being extroverted so he manages to speak his mind in front of others, and even rap. But he knows that the others think of him as gonk and wants to change it somehow, but that he doesn't have enough courage to. He's the best friend of both The Protagonist (who's also fat... every 12 hours) and Ji Ho, a thin weak guy.
- Carl Wheezer from The Adventures of Jimmy Neutron, is generally a straight mixture of a Type C (though not as big of a Cloudcuckoolander as Sheen) and a Type B (which one dominates depends on the episode), but can also be a Type A in occasional situations, generally as part of a facade.
- Atomic Betty has Penelope Lang's friend Megan. She's occasionally shown traits of all three types, but being a side character who barely talks she doesn't really get much development.
- Howard Weinerman of Randy Cunningham: 9th Grade Ninja is this to Randy, being a combo of "Big and Brash" and "Cloud Cuckoolander". However, his build isn't often pointed out; in fact, the one time it looked like they would (when he finds out that Randy didn't think he could climb the rope in gym class), it turns out Randy actually had his "dainty" hands in mind.
- Nikki in Sonic the Hedgehog has chubby best friend Little John who likes to eat.
- Patton Oswalt recounts an anecdote where he's at a Hollywood party and feeling depressed that he can't eat anything at the buffet because he's trying to lose weight and get more roles. Then he spots Brian Dennehy piling his plate with food and laughing, "Character actors! Who gives a fuck if we're fat?" Patton notes, "They're always going to need a fat best friend; that's never going out of style."
- In the "Blood and Ice Cream Trilogy," Nick Frost's characters play this role to Simon Pegg. None of them fit a type.
- In Shaun of the Dead, Ed is a boorish idiot and pot-dealing loser who becomes the group's Millstone when zombies attack.
- In Hot Fuzz, Danny Butterman is a sweet and naive young officer who desperately wants to be Action Hero.
- In The World's End, Andy is a former party animal turned straight-laced and successful professional who rediscovers his badassness.
- John Candy's character in Brewster's Millions (1985) to the protagonist played by Richard Pryor.
- John Candy's character in Splash to the protagonist played by Tom Hanks, who is also his brother.
- Charles in Super 8, who is the overweight best friend of the film's protagonist, Joe. He's the director of the group's amateur film.
- Fezzik in The Princess Bride to Inigo. It's not his fault that he's the biggest and the strongest. He doesn't even exercise.
- Vetch, Ged's best friend in Ursula K. Le Guin's Earthsea series, is fat but he is a more complex character.
- Jean Tannen in the Gentleman Bastard series is a fat guy, but also the main characters bodyguard and a Genius Bruiser.
- Seinfeld: Kramer's buddy and Jerry's antagonist Newman.
- Andy from According to Jim is Cheryl's brother and can be considered Jim's best friend.
- Friends: Monica was this to Rachel in high school. However its unclear which category she'd fit into, as she seems similar to present day: Dorky but also strong-willed and hard-working. (Neither of which fit the sterotype). Its also clear she did have friends outside of Rachel.
- Fima Korolyov from Guest from the Future, who is a teenage sci-fi geek.
- Jeremy's best friend Hector in Zits.
- Bobby Collins had a routine about the difficulties of the "Pretty Girl's Best Friend", a girl who is fat, unattractive, or otherwise off-putting that one has to be nice to if one wants to charm the target Pretty Girl, as the two are always together, but the PGBF's presence is enough to warp reality and cause small-scale mishaps.
- Nella is the BFF (Big Fat Friend) of the The Nostalgia Chick. She's been played as all three types, though her Type B tendencies have been played down over time. In fact she's sort of a Subversion: after a lot of heat from people who thought the Chick actually treated her like crap they put up a video revealing that she actually hired Nella to be her friend to boost her own fragile self-esteem.
- The Simpsons: Though Homer Simpson himself is quite overweight, his drunken buddy Barney Gumble is even more obese. He can be all three types Depending on the Writer (especially since quitting alcohol).
- Arthur, Lance's friend at Military School in the Whole Episode Flashback of Sym-Bionic Titan. He has traits of all three. Octus' Newton disguise could be seen as this to Lance and Ilana, although he doesn't really fall under any of the types.
- Angela Anaconda: Angela's best friend Gina Lash doesn't fit any of the categories. She's actually the smartest child in her grade, and her intelligence is her only other defining trait, other than being a Big Eater.
- Similar to the Gina Lash example, there's Sean from Ready Jet Go!, who's known for his intelligence and reluctance to go to space.