http://news.discovery.com/human/women-body-image.html
Body Image Concerns Hardwired Into Women's Brains
...While hooked up to brain scanners, the women looked at images of avatar-like models in skimpy bikinis: some overweight, some skinny. With each image, the women were told to imagine that someone else was saying the model looked like her.
When overweight images popped up, the medial prefrontal cortex lit up in all of the women, the scientists reported in the journal Personality and Individual Differences. Simply imagining that they might be overweight seemed to make the women question their sense of self, even though they claimed afterward that the test was boring or meaningless.
"Women are actually engaging in an evaluation of who they are and whether they are worthwhile as a person," Allen said. "Even though women might claim to be well adjusted and not care about body issues, subconsciously they might care."
Correction
Women don't LIKE TO think of themselves as fat...