http://static.tvtropes.org/pmwiki/pub/images/run-fat-boy-run01_1797.jpg

-> ''I'm not fat! I'm just... unfit...''

Dennis Doyle (Creator/SimonPegg) is a clueless and slightly overweight ManChild who left his pregnant fiancée Libby (Creator/ThandieNewton) at the altar five years earlier. He constantly tries to persuade the woman he loves to accept him back into her life, but when he discovers that Libby has found a new partner in the form of American Whit (Creator/HankAzaria), frustration grows, and Dennis vows that for once in his life, he will finish something. This something ends up being the Nike River Run in London. With his friend Gordon ([[Series/BlackBooks Dylan Moran]]) and landlord Mr. Goshdashtidar by his side, Dennis begins training for the marathon he must finish to win the respect of both Libby, and himself.

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!!This film provides examples of:

* TheAce: Whit; "[[WesternAnimation/WackyRaces Peter Perfect]]" as Dennis calls him.
* ActorAllusion: David Walliams' cameo is similar to his ''LittleBritain'' character who goes into shops asking for oddly specific things.
* AddedAlliterativeAppeal: "[[AlliterativeName Dennis Doyle]] from downstairs"
* AskAStupidQuestion: [[spoiler: After explicitly pointing out that Dennis is running on a broken ankle, the reporter then asks:]]
--> '''Reporter''': Sir! Sir! How do you feel?\\
'''Dennis''': (in ''tears'', barely cognizant) '''How the [[PrecisionFStrike fuck]] do you think I feel?!'''
* {{Blackmail}}: When Dennis refuses Maya's ultimatum to kick him out if he quits the race and pay his back rent if he doesn't, she whips away his ModestyTowel and takes a polaroid of his naked body. "Deal?" "...Deal."
* CreatorCameo: Director David Schwimmer can be seen giving a water bottle to Dennis in the race.
* CrankyLandlord: Played with; Mr. G is a cheerful, forgiving type, but [[UglyGuysHotDaughter his daughter]] Maya takes it upon herself to chase Dennis up for the rent.
* ChampionsOnTheInside
* CheatersNeverProsper: [[spoiler:Whit trips Dennis up, only to be sent to hospital himself while Dennis limps on, and later to get caught out by an action replay.]]
* ConsequenceCombo: There are a lot of carrots and sticks in play, but the clearest example of the trope is Maya's ultimatum - if Dennis finishes the race, she'll call off his back rent. If he doesn't, she'll kick him out.
* {{Crossdresser}}: who enjoys terrorizing Dennis the security guard, and is later shown [[ChekhovsSkill running the marathon.]]
* DerailingLoveInterests: Whit, who starts off TheAce and gets gradually more {{Control Freak}}y and competitive in direct contrast to Dennis getting more responsible and mature.
* DownToTheLastPlay: Hugely averted. [[spoiler:Whit is taken out of the race very early, and Dennis severely injured, and the rest of the marathon is spent limping in last place, [[ImplacableMan determined to finish]].]] All of which makes Jake's "[[CompletelyMissingThePoint dad, you won!]]" utterly heartwarming.
* EnforcedMethodActing: in the scene where Creator/SimonPegg and Hank Azaria are talking in the locker room, Simon's shocked reaction to Hank dropping his towel was very real. Apparently, Hank was supposed to wear a modesty patch over his genitals, but it didn't fit, so he did the scene without it.
* ExcitedShowTitle!
* TheFamilyForTheWholeFamily: A low-rent LondonGangster who appears to run a betting syndicate and fence stolen goods, who ''nearly'' breaks Gordon's hand in a piano lid, and who when his bet is threatened hijacks a taxi, drives to the race and... runs alongside Dennis taunting him and ineffectually trying to trip him up. Lampshaded after Mr. G rescues Gordon from the piano incident;
-->'''Mr. G.:''' Your friend is man of honour. He promised to beat shit out of you ''later''!
* FirstFatherWins
* GracefulLoser: Even the NeighbourhoodFriendlyGangsters who bet against Dennis are cheering him on when he crosses the finish line.
* GroinAttack
* GuessWhoImMarrying
* HeartIsWhereTheHomeIs
* IGaveMyWord: Somewhat justified despite the HonorBeforeReason, since his ability to keep a promise is what Dennis is ''really' trying to prove.
* ImplacableMan[=/=]TheDeterminator: Dennis, [[strike:running]] limping the best part of a ''marathon'' on a sprained, implied to be ''broken'' ankle because [[IGaveMyWord he promised he would, dammit!]]
* InconvenientItch: When he first starts working out, Dennis gets a nasty, itchy rash on his crotch that he absolutely has to scratch... as he is at work as a security guard in a lingerie shop. One can guess what this [[AccidentalPervert looks like]].
* IResembleThatRemark: in Libby's bakery;
-->'''Libby:''' You can't even finish your sentence! \\
'''Dennis:''' Oh... don't... don't... don't be... what's the word?
* IronicEcho: "No, but you can watch me do it."
* JerkJock: Whit.
* JerkWithAHeartOfGold: Gordon. He steals from people and bets everything on Dennis. However, he cares about him, Libby and Jake. Just look at the scene where [[spoiler: Jake has run away and Dennis tells Gordon about this.]]
* KentBrockmanNews: The overexcitable reporter. "He ''deliberately'' tripped him! ''Bastard!'' Sorry, got carried away again..."
** "And, what's that? ''[overjoyed]'' He's got a ''son!'' I didn't know he had a son! Did you know he had a son!?"
* LawyerFriendlyCameo: Dennis and Whit are running in an annual marathon in London on a Sunday, with space for a number of charity runners to enter after the general closing date, that is most definitely ''not'' the London Marathon.
* ManChild: Dennis's whole problem.
* ModestyTowel: Played with twice. Whit drops his in the changing room, giving Dennis an eyeful, and Maya whips Dennis' away after he gets out of the shower in order to take a blackmail photo.
* NeverMyFault: Dennis blames his problems that he caused on other people.
* NewscasterCameo: BBC Breakfast presenter Chris Hollins AsHimself, commentating on the race with Denise Lewis.
* NoodleIncident: Gordon's one serious relationship somehow ended with "a broken collarbone and a dead meerkat."
* OverAndUnderTheTop: Gordon basically exists to make lazy slacker Dennis look almost ambitious in comparison. But comparing him to Whit isn't quite so favourable.
* OverlyNarrowSuperlative: "That's the second most disgusting fluid I've ever had in my eye!"
* PantsFree: When Gordon invites Dennis into his apartment, he's leaning over the balcony. At the end of the conversation we see him shot from behind, revealing that he's naked from the waist down. At the end of the movie, he invites two beautiful girls onto his boat... again, no pants.
* ParentWithNewParamour: Averted at first, Jake is pretty impressed with Whit, which to Dennis just makes him even more [[AlwaysSomeoneBetter depressingly superior]]. However, they're never as close as he is with his dad, and when Jake really starts going off Whit you know the guy's doomed...
* PrecisionFStrike: Jake on Whit: "what a shithead..."
* ProductPlacement: For Nike, shamelessly. The "Nike River Run" is sponsored by Nike, there are Nike banners every 20 feet of the race, and the commentators and journalists keep saying "Nike." [[SelfDemonstratingArticle Nike.]]
* PleasePutSomeClothesOn: the locker room scene. See EnforcedMethodActing.
* RawEggsMakeYouStronger: As part of his TrainingMontage, Dennis attempts to drink about six raw eggs at once, but immediately spits them back up.
* ReactiveContinuousScream: Dennis and Gordon, when Dennis wakes up with an hour to get to the starting line.
* TheReasonYouSuckSpeech: Whit takes that relationship-as-marathon metaphor and drags it right out of the subtext to slap it in Dennis' stunned face.
* RunawayBride: Dennis is a runaway groom.
* ShoutOut:
** Dennis refers to Whit as "[[WesternAnimation/WackyRaces Peter Perfect]]".
** The reporter refers to ''The Loneliness Of The Long-Distance Runner'', a short story by Alan Sillitoe.
* TheyWastedAPerfectlyGoodSandwich: The spaghetti bolognese, becomes a plot point later on.
* TitleDrop: By the crossdresser, and later by Whit as he pulls away in the race.
* TrainingMontage: Parodied and played straight side-by-side.
* UglyGuysHotDaughter: Maya.
* TheUnpronounceable: Mr Gostust... Goshdash... Mr G. [[AllThereInTheScript For the record: Goshdashtidar.]]
* VisualPun: Whit and Dennis edge their way past a pair of runners dressed as a tortoise and a hare.
* WimpFight: [[http://www.youtube.com/watch?v=nUJS7OyOK2U A stellar example]].
* YaoiFangirl: the guys are in the middle of a NotWhatItLooksLike moment in a taxi when it stops in front of an attractive woman, who seems to like what she sees.
* YouAreFat: The TitleDrop, courtesy of the transsexual kleptomaniac. Dennis is really a [[HollywoodPudgy fairly scrawny guy with a beer gut]], but that doesn't stop him being self-conscious about it.
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