4. Jared Leto
If you have watched Dallas Buyers Club, you will know that Jared Leto has also worked hard to play an emaciated and dangerously thin character. It has been reported that he lost 30 lbs and weighed only 116 lbs during the shoot, and this could prove to be dangerous for his health. He even confessed of not eating anything so that he could lose weight to fit into the delicate and fragile character. However, Jared put on a lot of weight for other roles later on. Leto is an infamous method actor who’s always willing to go the extra mile.