Sydney Sweeney is pulling back the curtain on how she was able to quickly lose the weight she gained for her role in the new film, Christy. "I had to be really strict with myself," the actress, 28, said of her dieting plan after wrapping Christy in an interview with People published on Monday, December 10. "When I was training, it was really hard to put on all the weight." Sweeney previously shared that she had gained 30 pounds while training to portray boxer Christy Martin. "I was eating so much food. Like, everything you could possibly imagine," she continued.