With more than half of teenage girls and nearly a third of boys using unhealthy behaviors to control their weight, experts at the National Eating Disorders Association (NEDA) offer 10 tips to catch the warning signs of anorexia or bulimia:

• Dramatic loss of weight.
• Preoccupation with calorie-counting.
• Frequent use of a weight scale.
• Obsession with exercise.
• Binge eating and/or purging.
• Food "rituals" -- taking tiny bites, ignoring certain food groups, rearranging food on the plate.
• Eating alone, or avoiding meals altogether.
• Use of laxatives/diuretics.
• Smoking aimed at suppressing appetite.
• Frequent criticism of self as "fat," which increases despite weight loss.

NEDA experts note that the median onset of anorexia for girls is between the ages of 11 and 13, but the disease has been noted even in elementary school children.

And even though anorexia and bulimia carry the highest death rates of any psychiatric illness, a report issued Thursday by Harvard University researchers found that fewer than half of those with a history of an eating disorder said they had ever received treatment.