But the actress, 23, says she's learned to love her body, no matter what bloggers say about her looks.
"I wouldn't change my body, and I couldn't anyway," she tells Cosmopolitan UK's May issue. "The only way to be happy and be a more enjoyable person to be around is to embrace what you've got. I feel confident now."
Barton, who stripped down for the magazine's cover shoot, says it's "human nature to want to pick on other people, but I find it a little shallow ... Surely there are more important issues than if someone has cellulite?"
Of her split from The Kooks rocker Luke Pritchard, Barton says she's better off single.
"I've grown so much in the past six months," she says. "It's because I've been single. I've forced myself to grow up – I really felt like it was time. And nothing makes you grow like finding out that somebody or something isn't good for you."
Barton, recently cast in the CW pilot A Beautiful Life, says she is currently "happy and healthy" – and not looking for a new romance just yet.
"I've had great relationships and my exes have all been friends," she says. "For now, I'm happy being single."
