In the latest attempt by a Hollywood superstar to Oscar grub by radically transforming their physical appearance, former hard-body Colin Farrell is rapidly downsizing for his upcoming part as a war photographer in Triage. And while Farrell could use some credibility in the acting department following his recent string of flops, hacking off all these pounds doesn't look like the healthiest way to do it. But admittedly, dieting your way towards industry approval has been a Hollywood go-to trick for quite a while. We took a look back at some of his peers' most drastic weight losses, and as scary as the morphing process made them look, each part did bolster their respective careers dramatically:

Playing a prisoner of war in last year's critically acclaimed Rescue Dawn meant Steve Zahn, until then just another token funny buddy actor, was forced to lose 40 pounds on a diet of vegetables and nuts. As he put it, "I never cheated but it was tough - I'm a meat and potatoes kind of guy." As for Renee Zellweger, earning Oscar noms for both Chicago and Cold Mountain meant losing twice that much: "I lost 80 pounds for those two roles...my tits disappeared so I had to stuff socks into my bra cup!." And Matt Damon lost 30 to play the nerdy swindler star of 1999's bold-faced name-packed but Oscarless update of The Talented Mr. Ripley.

As a crack addict with a heart of gold in Half Nelson, Ryan Gosling went from Rachel McAdams' cute boyfriend to Oscar nominee by transforming into a gaunt tweaker. But of course, the most frightening metamorphosis of all time has got to be Christian Bale's unrecognizable appearance in The Machinist, a role which earned him just as many rave reviews as it did health problems. As Bale put it, going from 180 pounds to 120 caused "a massive shock to my body because of what I was trying to get it to do...My metabolism had to get back up to speed, because my heart had got used to a whole different way of living for some time."

• FARRELL GOES FROM TRIM TO THIN [The Sun]