Anorexia's Roots in the Brain
Obsessed with food
It began innocently enough with an hour a day of exercising to a Jane Fonda workout tape, but once Wendy Headrick began losing weight in eighth grade, she could not stop. Soon she quit eating candy, then fat and meat. By the end of the year, she says, "I was drinking water, eating cucumbers and other vegetables, and chewing gum to curb my appetite." Within 18 months, the 5-foot, 6-inch teen had dropped from 145 to 84 pounds.
Headrick had anorexia nervosa, the eating disorder that afflicts millions of American teenagers, most of them girls. Once thought to be entirely the result of cultural pressures on girls to be thin, anorexia and bulimia (also an eating disorder) are now thought to be related as well to changes in the brain that occur at puberty.
Headrick says the idea to lose weight occurred to her at age 13, when neighborhood children began teasing her for being overweight. Most pubescent girls find themselves gaining weight suddenly because their bodies must have a certain percentage of fat in order to mature sexually, says Sarah Leibowitz, a neurobiologist at Rockefeller University in Manhattan. As a girl enters puberty, her hypothalamus, a part of the brain that controls basic functions like sex and eating, starts churning out high levels of a neurochemical that stimulates appetite.
Obsessed. While all girls put on fat at puberty, only a fraction become focused on losing weight to the point of harming themselves. Headrick, now a 20-year-old junior at Ohio State, in Columbus, recalls, "I was obsessed with food. I would cook and cook and cook but not eat. I would watch what everybody else put in their mouths."
That obsessiveness may hold a clue to what's going on in an anorexic's brain, says Walter Kaye, director of the Eating Disorders Clinic at the University of Pittsburgh, where Headrick took part in a study. He has found that girls with eating disorders have higher than average levels of serotonin, a brain chemical that helps transmit electrical signals between neurons. People with high levels, says Kaye, "tend to be obsessive, anxious perfectionists. They are the best little girls in the world." This need to be perfect may start them on the road to starvation, but what keeps them going, Kaye suspects, is the discovery that starving themselves makes them feel better. Food contains a component of a protein that's necessary for the body to manufacture serotonin. Starving themselves may ease their anxieties by lowering the levels of serotonin in their brains.
This story appears in the August 9, 1999 print edition of U.S. News & World Report.
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