Kelly Clarkson once suffered from bulimia.The 'American Idol' winner developed the eating disorder after missing out on a role in her high school musical. She told Cosmo Girl magazine: "I thought if I came back and I was cuter and thinner - then I'll get the role."Kelly, 25, struggled with bulimia for six months until friends discovered her secret and begged her to get help. She said: "One of my guy friends caught on to it, and I just felt so ashamed and embarrassed. I literally went cold turkey and snapped out of it."Since beating the eating disorder, the singer vowed to be more positive about her body and promote healthy eating to her fans. Kelly said: "I've got a butt, I'm Greek - I can't help that. And I think it's good for people to see normal. I love food far too much!"