5. Renee Zellewegger
In order to portray the role of Bridget Jones in Bridget Jones Diary, Renee added 30 lbs to her figure in just three months. Although, the doctors told her that such a transformation can be very unhealthy, Renee was determined to fit into her character as best as shoe could. To put on the excessive weight, Renee had to be on a disgusting diet every day, binge eating and gorging on junk food without any exercise.