Our "training" begins early. In a University of Central Florida study of three- to six-year-old girls, nearly half were already worried about being fat—and roughly a third said they wanted to change something about their body. "There are only so many times you can be hit with the message that your body isn't right'—whether you see it on TV, hear it from your mom or just feel it in the ether—before you internalize it and start beating yourself up for not being as perfect as you should' be," says Nichole Wood—Barcalow, Ph.D., a psychologist at the Laureate Eating Disorders Program in Tulsa, Oklahoma. As Maureen Dorsett, 28, of Washington, D.C., who counted 11 negative thoughts the day she did our experiment, puts it: "I always saw my negative thoughts as a way of improving myself—of calling attention to what I need to work on. If a guy said to me, Wow, your belly looks flabby today,' that would be really offensive. Somehow, these thoughts never seemed as degrading coming from my own mind. Maybe I had just gotten so used to having them."

To make matters worse, negative talk has become part of the way women bond. "Friends getting together and tearing themselves down is such a common thing that it's hard to avoid," says Kearney-Cooke. The chatter happens on Facebook and among coworkers, and is broadcast with surprising viciousness on shows like Real Housewives and Bridalplasty (on which one perfectly cute contestant declared, "I want this butt face fixed!"). And all that public bashing makes the internal insult-athon seem normal. As one woman told us, "When others make comments about their bodies, it makes me think about mine more."

Hmm. If our brains are virtually wired this way—and outside cultural forces aren't helping—how can we stop the self-hate? We were determined to find out.

When Glamour analyzed the data to look for a cause of these ruthless thoughts, a fascinating trend emerged: Respondents who were unsatisfied with their career or relationship tended to report more negative body thoughts than women who were content in those areas. What's more, feeling uncomfortable emotions of any sort—stress, loneliness, even boredom—made many women start berating their looks. "If we're having a bad day, we often take those negative emotions out on our body, rather than directing them at what's really troubling us, like our boss or boyfriend," says Wood-Barcalow. In fact—and this part's important—whether you're unhappy in general is a much larger factor in how you feel about your body than what your body actually looks like. In our survey, thin and average-weight women were just as likely to insult themselves as overweight ones. As Wood-Barcalow recites to her patients: "It's all about your body—and absolutely nothing about your body."

Consider: "Let's say you're in a meeting and you suddenly think, Ew, my arms are huge," says Kearney-Cooke. "Well, you've had those same arms all day. Why are you suddenly feeling bad about them now? Maybe it's because you don't think your professional ideas are being valued or you're not fulfilled in your job. Instead of focusing on the real issue, all you can think of is hating your arms. And it becomes a vicious cycle: All the push-ups in the world won't make you feel better, because your arms weren't the problem to begin with."

So how can you muzzle that insulting internal voice and get on with your life? "I'm way too hard on myself, but I don't know how to lessen my negative thoughts," admits Rebecca Illson, 25, of Birmingham, Michigan, who counted 50 of them over the course of the day. And that age-old advice to "love your body" is—let's be honest—trite and unhelpful. "It's not about achieving a perfect' body image. That's not realistic," says Wood-Barcalow. "Even the most confident women have doubts. But they've learned to combat those thoughts rather than allow them to take over."