A-list movie stars are very committed to their craft. And producers and casting directors are often looking for something very specific when they cast their movies. So it’s no wonder actors have drop 60 pounds in a couple of months to play the role of a skeletal, disturbed insomniac or drank melted pints of Häagen-Dazs mixed with olive oil to convincingly play the part of an overweight assassin.

While Christian Bale is the undisputed king of morphing his body for each new role, many actors have given up their favorite foods—or, alternatively, ate loads of cupcakes and cheeseburgers—to convince the audience that they are the character they’re playing. Here, we take a look at the most severe celebrity cases of weight loss and gain, and investigate the diets and workout regiments the actors followed to either bulk up or slim down for a movie role.

From eating 5,000 calories a day to eating nothing but lattes and apples, see how your favorite celebrities managed to bulk up or slim down for movie roles.