Although most of us love food, a growing number view it as the enemy. Take Leslie Lipton, one of the millions of women with eating disorders such as anorexia and bulimia.

In eighth grade, when Leslie’s body filled out before her friends, she began to refuse second helpings. Then she skipped food. Then she vomited every morsel she ate. “At one point I feared food as the ‘army of calories,'” she says.

When she grew gaunt, a teacher and a best friend sounded the alarm. Leslie entered a six-week treatment program. She reached her weight goal and later wrote a book, Unwell, based on her story.

More Americans than ever may mirror Leslie’s tale. In a recent poll, for instance, nearly one in five U.S. college students admitted to an eating disorder.

While disordered eating tends to start with girls ages 11 to 13, “we’re now seeing more kids as young as 8, as well as boys and midlife women,” says Richard L. Levine, MD, an eating disorders specialist in Hershey, Pa.

Borderline disorders

There also may be untold numbers with borderline eating disorders. Dubbed EDNOS—for “eating disorders not otherwise specified”—these fall outside the diagnostic criteria for eating disorders. With no diagnosis, treatment is harder to get, says Douglas Bunell, PhD, clinical director of the Renfrew Center in Connecticut. “Without intervention, these behaviors, like drug addiction, could become more serious.”

In February 2007, a Harvard study estimated binge eating affects more than eight million Americans in the course of their lives. Anorexia afflicts nearly two million and bulimia nearly three million. Women account for two out of three cases, the study found.

What’s behind the rise in eating disorders? For one thing, experts’ growing awareness may lead to more diagnoses. Another reason: A weight-obsessed culture bombarded by media “thin” messages. More than half of American women are trying to lose weight at any time. Many will develop an eating disorder, the National Eating Disorders Association says.

Whether you develop an eating disorder depends on a mix of “nature” vs. “nurture” factors. “Certain people appear to have brain chemistry that influences disordered eating,” says Timothy Walsh, MD, professor of psychiatry at Columbia University. Eating disorders run in families, especially among members with perfectionist, obsessive-compulsive traits. Adolescent stress plays a role, too.

The right mix of factors may lead to anorexia, marked by a distorted body image. People with anorexia severely restrict calories, usually by vomiting or excessive exercise, often to the point of extreme emaciation. The health toll can range from hair loss and missed periods to brittle bones, heart failure, and, in a third of cases, death.

Secretive behavior

Bulimia involves eating mass quantities of calories, then vomiting or using laxatives. “Detection is tricky because bulimics are normal weight and can keep their behavior secret,” says Dr. Bunell. The result can be tooth decay (from vomiting) and an electrolyte imbalance that can affect heart rhythm.

The antidepressant fluoxetine, along with other behavioral therapies, helps treat bulimia if it’s caught early. Also promising is the Maudsley Method, a “food is medicine” approach that involves nurturing, one-on-one supervision by parents. “There’s convincing data that the Maudsley Method can reverse anorexia in a relatively short amount of time,” says Dr. Walsh.

But the key to success in treating eating disorders is early detection and intervention. Here’s what parents can do:

  1. View dieting or excessive exercise as a red flag. “It’s normal and crucial for preteens to put on weight,” says Dr. Bunell. Make sure your child meets growth benchmarks. If picky eating lasts and your child is losing weight, see a pediatrician.
  2. Help children deal with the media flood of “thin is in” images. Teach them that a slender body doesn’t mean power, popularity, or perfection.
  3. Normalize eating. Have set mealtimes, don’t restrict food, and eat from all food groups in moderate portions. Teach children to heed hunger signals.
  4. Don’t make dieting or losing weight a key part of family life.
  5. Make sure your child doesn’t tap Web sites that promote unhealthy weight loss.