Question: What dramatic physical alteration to his body did Brad Pitt make for his role in Fight Club and why?
About the article "Fight Club", section "Casting".

Candidate passages:
Woodhall was a body double for Brad Pitt in a fight scene in the movie Snatch, directed by Guy Ritchie.
He trained Matthew Marsden for his role in the movie "Shiner". 
In 1999, Pitt portrayed Tyler Durden in "Fight Club", a film adaptation of Chuck Palahniuk's novel of the same name, directed by David Fincher.
Pitt prepared for the part with lessons in boxing, taekwondo, and grappling.
To look the part, Pitt consented to the removal of pieces of his front teeth which were restored when filming ended.
While promoting "Fight Club", Pitt said that the film explored not taking one's aggressions out on someone else but to "have an experience, take a punch more and see how you come out on the other end."
"Fight Club" premiered at the 1999 Venice International Film Festival.
Despite divided critical opinion on the film as a whole, Pitt's performance was widely praised.
Paul Clinton of CNN noted the risky yet successful nature of the film, while "Variety" remarked upon Pitt's ability to be "cool, charismatic and more dynamically physical, perhaps than ... his breakthrough role in "Thelma and Louise"".
In spite of a worse-than-expected box office performance, "Fight Club" became a cult classic after its DVD release in 2000.
Following "Fight Club", Pitt was cast as an Irish Gypsy boxer with a barely intelligible accent in Guy Ritchie's 2000 gangster film "Snatch".
Several reviewers were critical of "Snatch"; however, most praised Pitt.
Mick LaSalle of the "San Francisco Chronicle" said Pitt was "ideally cast as an Irishman whose accent is so thick even Brits can't understand him", going on to say that, before "Snatch", Pitt had been "shackled by roles that called for brooding introspection, but recently he has found his calling in black comic outrageousness and flashy extroversion;" while Amy Taubin of "The Village Voice" claimed that "Pitt gets maximum comic mileage out of a one-joke role".
The following year Pitt starred opposite Julia Roberts in the romantic comedy "The Mexican", a film that garnered a range of reviews but enjoyed box office success.
Pitt's next role, in 2001's $143 million-grossing Cold War thriller "Spy Game", was as Tom Bishop, an operative of the CIA's Special Activities Division, mentored by Robert Redford's character.
Mark Holcomb of Salon.com enjoyed the film, although he noted that neither Pitt nor Redford provided "much of an emotional connection for the audience".
On November 22, 2001, Pitt made a guest appearance in the eighth season of the television series "Friends", playing a man with a grudge against Rachel Green, played by Jennifer Aniston, to whom Pitt was married at the time.
For this performance he was nominated for an Emmy Award in the category for Outstanding Guest Actor in a Comedy Series.
In December 2001, Pitt had the role of Rusty Ryan in the heist film "Ocean's Eleven", a remake of the 1960 Rat Pack original.
He joined an ensemble cast including George Clooney, Matt Damon, Andy García, and Julia Roberts.
Well received by critics, "Ocean's Eleven" was highly successful at the box office, earning $450 million worldwide.
Pitt appeared in two episodes of MTV's reality series "Jackass" in February 2002, first running through the streets of Los Angeles with several cast members in gorilla suits, and participating in his own staged abduction in another episode.
In the same year, Pitt had a cameo role in George Clooney's directorial debut "Confessions of a Dangerous Mind".
He took on his first voice-acting roles in 2003, speaking as the titular character of the DreamWorks animated film "" and playing Boomhauer's brother, Patch, in an episode of the animated television series "King of the Hill". 
Producer Ross Bell met with actor Russell Crowe to discuss his candidacy for the role of Tyler Durden.
Producer Art Linson, who joined the project late, met with another candidate, Brad Pitt.
Linson was the senior producer of the two, so the studio sought to cast Pitt instead of Crowe.
Pitt was looking for a new film after the failure of his 1998 film "Meet Joe Black", and the studio believed "Fight Club" would be more commercially successful with a major star.
The studio signed Pitt and offered him a $17.5 million salary.
For the role of the unnamed narrator, the studio desired a "sexier marquee name" like Matt Damon to increase the film's commercial prospects; it also considered Sean Penn.
Fincher instead considered Edward Norton a candidate for the role, based on the actor's performance in the 1996 film "The People vs. Larry Flynt".
Other studios were approaching Norton for leading roles in developing films like "The Talented Mr. Ripley" and "Man on the Moon".
The actor was cast in "Runaway Jury", but the film did not reach production.
20th Century Fox offered Norton a $2.5 million salary to attract him to "Fight Club".
Norton could not accept the offer immediately since he still owed Paramount Pictures a film; he had signed a contractual obligation with Paramount to appear in one of the studio's future films for a smaller salary (Norton later satisfied the obligation with his role in the 2003 film "The Italian Job").
In January 1998, 20th Century Fox announced that Brad Pitt and Edward Norton were cast in the film.
The actors prepared for their roles by taking lessons in boxing, taekwondo, grappling, and soapmaking.
Pitt voluntarily visited a dentist to have pieces of his front teeth chipped off so his character would not have perfect teeth.
The pieces were restored after filming concluded.
Fincher's first choice for the role of Marla Singer was Janeane Garofalo, who objected to the film's sexual content.
The filmmakers considered Courtney Love and Winona Ryder as candidates early on.
The studio wanted to cast Reese Witherspoon, but Fincher objected that she was too young for the role.
He chose to cast Helena Bonham Carter based on her performance in the 1997 film "The Wings of the Dove".
Fight Club is a 1999 American film based on the 1996 novel of the same name by Chuck Palahniuk.
The film was directed by David Fincher and stars Edward Norton, Brad Pitt, and Helena Bonham Carter.
Norton plays the unnamed protagonist, an "everyman" who is discontented with his white-collar job.
He forms a "fight club" with soap maker Tyler Durden, played by Pitt, and they are joined by men who also want to fight recreationally.
The narrator becomes embroiled in a relationship with Durden and a dissolute woman, Marla Singer, played by Bonham Carter.
Palahniuk's novel was optioned by 20th Century Fox producer Laura Ziskin, who hired Jim Uhls to write the film adaptation.
Fincher was one of four directors the producers considered.
They hired him because of his enthusiasm for the film.
Fincher developed the script with Uhls and sought screenwriting advice from the cast and others in the film industry.
The director and the cast compared the film to "Rebel Without a Cause" (1955) and "The Graduate" (1967).
Fincher intended "Fight Club"s violence to serve as a metaphor for the conflict between a generation of young people and the value system of advertising.
The director copied the homoerotic overtones from Palahniuk's novel to make audiences uncomfortable and keep them from anticipating the twist ending.
Studio executives did not like the film and they restructured Fincher's intended marketing campaign to try to reduce anticipated losses.
"Fight Club" failed to meet the studio's expectations at the box office and received polarized reactions from critics.
It was cited as one of the most controversial and talked-about films of 1999.
However, the film over the years found critical and commercial success with its DVD release, which established "Fight Club" as a cult film.