Jennifer Lawrence doesn’t really diet for films, but she did for her new movie Red Sparrow.

“Red Sparrow was the first time that I was really hungry, and disciplined,” she told Vanity Fair. “I can’t be in character as an ex-ballerina and not feel like an ex-ballerina.” She added, “I can’t work on a diet. I’m hungry. I’m standing on my feet. I need more energy. I remember having a meltdown, freaking out that I had eaten five banana chips.”

“She really trained a tremendous amount,” director Francis Lawrence said. “She worked with a ballet coach for three months and did a lot of exercise.”

“I’ve always wondered what it would take to get me to really diet, to really be hungry, because I’ve never done it for a movie,” she said. “For Hunger Games, they told me to lose weight, and then I discovered Jack in the Box.”