THERE was not a minute in the day Claire Mysko didn’t think about what she put in her mouth.

"One of the things that I think about a lot, is the amount of time that I wasted in my life because I was so consumed with thoughts about food," says the 24-year-old, of suffering from anorexia and bulimia.

Mysko’s path to eating disorders was typical. She embarked on her first diet in the eighth grade, with a group of friends. In high school, she became anorexic, dieting herself down from 110 pounds to 90 pounds on a 5-foot-2-inch frame.

"I got a thrill from losing all the weight," says Mysko, now Administrative Director of the American Anorexia Bulimia Association. "It was difficult to stop."

One out of every one hundred young women between the ages of 10 and 20 is voluntarily starving herself, and four percent of college women are refusing to keep down the food they ingest, according to Anorexia and Related Eating Disorders. Though eating disorders have existed for centuries, their causes are complex and still debated by experts.