More from EW
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Gained for: The Five-Year Engagement
Lost for: Guardians of the Galaxy
Pratt added a little padding to his schlubby, tubby Parks and Rec body to play a chef in the 2012 rom-com, but he had to drop the recreational booze to convincingly embody superheroism in Guardians. The star credited a beer-free diet for his cut-from-marble and Marvel-ready physique.
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Gained weight for: Magic Mike
Lost weight for: The Dallas Buyer's Club
Playing on his reputation for shirtlessness, McConaughey played Dallas, the owner of a male dance revue in Steven Soderbergh's 2012 stripper flick (pictured, left). But paparazzi shots from the set of another Dallas—Dallas Buyers Club, for which McConaughey dropped 47 pounds to play a renegade AIDS survivor—created major buzz. In March 2014, McConaughey publicly gained 8.5 pounds in the form of a Best Actor Oscar statuette.
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Gained weight for: American Psycho
Lost weight for: The Machinist
Though his most dramatic physical feats came in the form of American Psycho's body-obsessed Master of the Universe Patrick Bateman (left) and The Machinist's haunted insomniac Trevor Reznik (for which he lost 63 pounds; right), those films didn't do big box office. It was another thinnification — a 30-pound drop to portray real-life boxer-turned-heroin-addict Dicky Eklund in 2010's The Fighter — that netted him an Oscar and proved that, from Batman to Bateman, there's Method to Bale's madness.
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Gained weight for: Monster
Lost weight for: Sweet November
After shedding 16 pounds to play a woman with terminal cancer in the 2001 melodrama misfire (right), the former model went a step further — shedding her vanity and packing on 30 pounds to embody prostitute serial killer Aileen Wuornos in Monster (left). Well, make that 38.5 pounds if you factor in the Oscar she gained.
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Gained weight for: Body of Lies
Lost weight for: Gladiator
Losing has been a winning formula for Crowe, who has publicly addressed his battles of the bulge over Twitter. Though his 63-pound puff-up for Lies (left) was a critical hit, the ripped and roaring role of Maximus in Gladiator (right) was the one that got him the gold.
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Robert De Niro
Gained — and Lost — weight for: Raging Bull
Chronicling the life of boxer Jake LaMotta in the 1981 Scorsese classic, De Niro's weight may have fluctuated by as much as 60 pounds, but his focus was unwavering. The benchmark performance earned him his first Best Actor Oscar.
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Gained weight for: Bridget Jones's Diary and Bridget Jones: The Edge of Reason
Lost weight for: Chicago
Loss or gain, Zellweger is second only to Robert De Niro in her ability to leverage weight shifts for Academy accolades. Upsizing by 30 pounds to play the British diarist in 2001 (left) earned her a nod, as did her lithe dancer's body (the product of a reported two-hour-a-day, six-day-a-week workout regimen) in Chicago (right).
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Gained weight for: The Informant!
Lost weight for: Courage Under Fire
For his role in Courage (right), Damon dropped 40 pounds to play a troubled war vet with a heroin habit. As he got more famous, the Ocean's Thirteen star enjoyed ribbing his co-star McConaughey for his penchant for shirtlessness. But the joke was on Damon when director Stephen Soderbergh told him to show off his 30-pounds-heftier gut for the 2009 film (left).
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Gained weight for: Chapter 27
Lost weight for: Dallas Buyers Club
Leto lived on a diet of ice cream and pizza to balloon 67 pounds for his portrayal of John Lennon's killer Mark David Chapman in 27 (left). Though he'd previously trimmed off 25 pounds to play a heroin junkie in 2000's Requiem for a Dream, Leto mirrored his Dallas Buyers costar Matthew McConaughey's extreme weight loss regimen—and his path to the Oscar podium—and shed 40 pounds to play drug-addicted AIDS sufferer Rayon.
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Gained weight for: Get Rich or Die Tryin'
Lost weight for: All Things Fall Apart
The rapper-actor shriveled his normally rippling physique by 54 pounds to play a cancer patient in 2011 (right). Even after blog buzz, though, the film went straight to DVD. Hopefully 50 (né Curtis Jackson) pumped back up with his much more profitable VitaminWater.
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Gained weight for: Alexander
Lost weight for: Triage
Farrell's 44-pound slim-down to play a PTSD-afflicted photojournalist (right) generated plenty of buzz as he was filming, but — like 50 Cent — it ended up being a bust when the film skipped theaters and headed straight to DVD in the U.S. Then again, going blonde and bulking up for 2004's Alexander (left) was another epic fail. Lesson for Farrell: We like you just the way you are.
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Gained weight for: Full Metal Jacket
Lost weight for: Adventures in Babysitting
D'Onofrio's no small fry to begin with, but his 70-pound uptick to play Private Pyle in Kubrick's war story (left) remains the biggest beef-up in film history. It took him nine months to take off the weight so he could suit up as Thor in Adventures (right).