Imagine you're a relatively thin young woman who thinks she has no issues with food or dieting—certainly no eating disorder. You see a picture of a swimsuit-clad woman with chunky thighs, a noticeable belly and arms that could benefit from a regular triceps routine. Suddenly your brain starts whirring anxiously and you wonder, do I look like that?
Now imagine you're a slim guy, also with no history of eating problems. You see a picture of a man in a swimsuit who looks like he's enjoyed more than his share of fries, beer, and double cheeseburgers. Your reaction is quite different from the woman's—at least according to researchers at Brigham Young University who conducted an experiment just like this.
Neuroscientist Mark Allen and his colleagues used imaging technology to watch brain activity in 19 men and women as they looked at computer-generated pictures of fat people in swimsuits. The nine male subjects in his study didn't appear to make any comparison between a picture of a fat guy and their own bodies. But the part of the brain involved in self-reflection (the medial prefrontal cortex) jumped into action when the 10 women looked at images of fat women, Allen says.
Are any women truly comfortable in their own skin? This admittedly small experiment can't answer that question for everyone, but it does raise some provocative issues, particularly about the influence of media images. Women are constantly barraged by complex and sometimes even bizarre messages about what constitutes attractiveness. The current female ideal is clearly not found in nature: big boobs, tiny waist, long slender legs, and perfectly symmetrical features. We may sneer at Heidi Montag’s plastic surgery, but a part of our brain is unconsciously doing a little comparison. Chubby male stars like Alec Baldwin can still be considered sexy, but a woman with a little heft gets her best shot at fame as a contestant on The Biggest Loser.
The result is a culture in which women are afraid of even a little fat, as though it were some virulent plague. That attitude is messing with our heads, as this study demonstrates. Allen's research, published in the May issue of the Personality and Individual Differences journal, grew out of work that he and his colleague Diane Spangler, a psychologist, were conducting on bulimics. Their goal was to establish a biological marker for healthy women's brains that they could compare to the brains of bulimic patients before and after treatment. So they set out to find a control group of women who appeared to have a healthy body image—which wasn't an easy task. "It was kind of hard to find women who were really thin but had no history of an eating disorder," Allen says.
The women who were ultimately selected were shown the images and then asked, "How would you feel if somebody said you looked like that?" The brain-imaging results were startling, Allen says. "Their activations were really close to the bulimics," Allen says. Bulimics did have some additional activity in a part of the brain involved in extreme negative thinking (the ventral anterior cingulate gyrus), but otherwise there wasn't a whole lot of difference between the supposedly "normal" women and the bulimics, Allen says.
One of his graduate students, Tyler Owens, suggested looking at men's brains as well because they generally have fewer problems with body image than women. "We saw absolutely no activity in the medial prefrontal cortex," as we did with women, Allen says. But he doesn't think that there's something special about men's brains that immunizes them from body issues. "I don't think it suggests a biological difference," he says. In fact, he originally included a few men in the study who were "obvious bodybuilders—big muscles, very low body fat." Their brains behaved much like those of the bulimic women (they were removed from the study). "They have that same obsession that the bulimic might have," Allen says. "They are highly vigilant about their intake. They will purge and do all sorts of things. That kind of suggests that it's not a genetic disposition but is just a social and cultural environment."
Figuring out the causes of eating disorders like bulimia is still a relatively new science. Much of the research so far has focused on the impact of culture on body image, says Rachel Marsh, assistant professor of clinical psychology at Columbia University's division of child and adolescent psychiatry. But Marsh adds that there's also good evidence that bulimia is a multifaceted disorder, and that genetics plays a role. "We know there is a familial component," Marsh says. "Daughters of bulimic mothers are more likely to develop bulimia than others, but we don't know if that's because of genetic or environmental factors since they are both living in the same home." The different responses by men and women in the BYU study echo other gender differences. Bulimia affects about four times as many females as males, although researchers don't know why. Bulimics tend to be more impulsive than the general population, Marsh says, "not just in the way they eat, but their impulsivity can also play out as shoplifting and cutting themselves." Girls with self-regulation control issues seem more likely to develop bulimia, while boys are more likely to develop Tourette's syndrome or obsessive-compulsive disorder. "We don't why any of this is," says Marsh.
Aside from cultural influences, brain development also plays a role in the development of bulimia. The brain's capacity for controlling impulses typically increases dramatically through adolescence and young adulthood. Based on the brain scans she's done, Marsh says there's good reason to think that abnormal development of the brain's self-regulatory control system increases an individual's vulnerability to binging and purging. She is hoping to begin a longitudinal brain-scan study of adolescents to monitor both the progression of the brain's self-regulation control system and eating disorders to better understand that relationship.
Someday that research may help unravel why men and women respond so differently to cultural messages. But until then, we have to do a better job of learning to love that woman in the mirror.