Getting into character for a movie role isn't just about putting on a costume and memorizing lines. Celebrities sometimes need to gain or lose a couple of pounds too--or maybe 40 to 50 of them!

Matthew McConaughey recently lost 30 pounds to play the role of a character with HIV in the upcoming movie The Dallas Buyers Club, but that's not out of the ordinary in Hollywood. A-listers are often asked to go the extra mile for their mega-paychecks by gaining or losing crazy amounts of weights in a short period of time, which leads to a whole bunch of methods no doctor would ever advise! From Beyonce to Ryan Gosling, check out the 14 craziest celebrity weight losses and gains of all time!

What weight gaining actor had beer and McDonald's as a daily in-between meal while on set? Find out after the jump!