Actors are known for sometimes going to extremes to prepare for a role.

Certain actors have gone through extreme weight loss transformations to prepare for a role.

And oftentimes, the lengths they go to are unhealthy andborderline dangerous.

Christian Bale

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And for more celeb news, read8 Best Healthy Snacks That Celebs Love.

Mila Kunis took up smoking again for ‘Black Swan.’

“Twelve hundred calories and I smoked…I don’t advocate this at all.

Mila Kunis

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It was awful.”

Anne Hathaway ate oatmeal paste for ‘Les Mis.’

Hathaway lost a total of 25 pounds for her role as Fantine in “Les Miserables.”

Anne Hathaway

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According to Vogue, Hathaway ate only two pieces of oatmeal paste a day to drop the weight.

“I had to be obsessive about itthe idea was to look near death,” she tells Vogue.

Christian Bale ate an apple a day for ‘The Machinist.’

Christian Bale

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Bale may be one of the most extreme actors when it comes to transforming his body for a role.

In fact, Bale now admits that his past methods of transforming for a role have to stop.

He toldThe Sunday Timesin 2019 that “I can’t keep doing it.

Zoe Kravitz

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I really can’t.

My mortality is staring me in the face.”

I ended up drinking clay, because it cleans out your body and fills you up.

Matthew McConaughey

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I was eating like a Mason jar of pureed vegetables a day and running."

Matthew McConaughey ate tapioca pudding for ‘Dallas Buyers Club.’