The threat of a piece of pumpkin pie.

Some people with the eating disorder anorexia nervosa may have an actual fear of food, according to a new study. Alan J. Strohmayer of the North Shore University Hospital in Manhasset, N.Y., and his colleagues found that people with anorexia nervosa experienced a stress response, detected by activation of their sweat glands, when simply viewing photos of pizza, pasta, ice cream, and other foods. People with bulimia, who deliberately vomit after eating, didn't react in the same way.

The researchers tested five women with anorexia nervosa and five with bulimia. On average, sweat gland activity in those with anorexia nervosa increased by 52 percent when they saw the images of a dozen different foods.

Many psychologists argue that anorexia nervosa stems from a fear of gaining weight, which causes people to avoid eating and, in some cases, to starve themselves to death. A food phobia, says Strohmayer, hasn't been considered before. It's not surprising that people with bulimia don't share this phobia, since they don't refrain from eating, he adds.

Strohmayer notes that current psychological treatments for anorexia nervosa often prove unsuccessful. He suggests that people with the eating disorder might be treated with desensitization therapy. Patients would be gradually exposed to their phobia--food--more often. This approach has worked for people with fears of flying and spiders, for example.