The warning signs that your teen may suffer from an eating disorder aren't always easy to spot.

We recently caught a Today show story about Alexandra Michael, a teen who left modeling because of the pressure from the fashion industry to stay thin. When she started out at 5 feet, 9 inches and 130 pounds, she was told her legs were fat--so she began to starve herself in order to lose nearly 30 pounds to keep up with the competition.

When clumps of her hair starting falling out and she stopped getting her period, Alexandra realized it was time to put an end to this dangerous fixation with her weight. She decided to speak out against the pressure placed on teen models who oftentimes battle bulimia and anorexia just so they can hold onto their careers. Alexandra's story is featured in this month's issue of Teen Vogue.

"Today we are seeing a really broad range of eating disordered behavior, including extreme dieting, over-exercise, and skipping meals. While not all teens reach the point of having an anorexia or bulimia diagnosis, millions of them do fall into those gray areas," says Claire Mysco, author of Girls Inc. Presents: You're Amazing! A No-Pressure Guide to Being Your Best Self. "The bottom line is that if your child's thoughts about food and weight are preventing her from feeling good about herself and enjoying her life, that is enough of a sign to seek help from a professional."

We spoke with Dr. David B. Herzog, author of Unlocking the Mysteries of Eating Disorders, momlogic friend Counseling Mom, Roseanne Tobey, L.P.C., and Claire Mysco, who is also founder of Inside Beauty, for important warning signs that parents can look for in teens who may be suffering from bulimia or anorexia.

5 Top Signs of Anorexia or Bulimia:

1. Extreme food restriction: The teen has a drastic change in her eating habits.  For instance, she is only willing to accept really small portions and then pushing them around the plate instead of eating them.

2. Perceives her body or parts of her body as extremely large when that is not the case: This may result in a change in clothing style. A daughter who has lost a lot of weight and is now wearing baggy clothing.

3. Disappearance of food from refrigerator or pantry: Bingers usually binge in secret, so keep an eye out for pantries or fridges that have been emptied of their contents, as well as large amounts of empty food wrappers either in the garbage or stashed in some out of the way place.

4. Excessive, compulsive exercise: An obsession with exercising--for instance several times a day, or to the point of complete exhaustion. 

5. Extreme weight loss or marked fluctuations in weight: Dramatic weight loss can be a sign of anorexia, but it is important to remember that not all eating disorders result in weight loss. Many bulimics are normal weight and they can even be overweight. That doesn't make their eating disordered behavior any less dangerous. Watch out for frequent trips to the bathroom after meals and excessive exercise (specifically increased discussion about needing to burn off calories). If you find any evidence that your child has been abusing laxatives or diet pills, confront her immediately.

The earlier a patient is diagnosed and treated with an eating disorder, the more likely they will recover completely. However, according to Walden, one of the country's leading hospitals for treating eating disorders, prolonged bouts with bulimia and anorexia that go untreated can result in osteoporosis, retarded growth, kidney problems, ulcers and heart failure and even death.

For more information about teens and eating disorders visit the Harris Center for Eating Disorders or Walden Hospital.