While some actors rely on prosthetics for movie transformations, some actually gain or lose weight to embody their characters.

Renée Zellweger famously gained 30 pounds to play the titular role in 2001’s Bridget Jones’s Diary, repeating the process again for the 2004 sequel, Bridget Jones: The Edge of Reason. By the time she filmed Bridget Jones’s Baby, however, the Oscar winner was tired of talking about her weight.

“I put on a few pounds. I also put on some breasts and a baby bump,” she told British Vogue in August 2016. “Bridget is a perfectly normal weight and I’ve never understood why it matters so much. No male actor would get such scrutiny if he did the same thing for a role.”

To Zellweger’s point, male stars more often make headlines when they lose a lot of weight for a role, as Matthew McConaughey did for the 2013 film Dallas Buyers Club. The Mud star shed nearly 50 pounds to play Ron Woodruff, a real-life Texan who founded an underground medication distribution group after being diagnosed with HIV. (McConaughey won a Best Actor Oscar for the role.)

Read Related Also: Fans convinced pregnant Jessie James Decker hinted at fourth baby’s sex

“I did it in as healthy a way as I found possible,” the Greenlights author told the BBC in February 2014, adding that he “chewed a lot of ice” during the shoot. “I met with a nutritionist. I gave myself four months to lose the weight. I had my programmed meals, lost 3.5 pounds a week — like clockwork — and got down to my desired weight, which turned out to be 47 pounds lighter.”

Keep scrolling to see which celebrities have gained or lost weight for movie roles: