America's obsession with appearance is out of control, and it's having a profound impact on our teenagers. Fifty percent of all teenage girls are practically starving themselves to stay thin.

According to one study, 50 percent of teenage girls always skip breakfast and do not know proper eating habits. Fifteen percent would consider taking laxatives or making themselves sick to keep their weight down. What we are talking about here is bulimia.

Bulimia is an illness defined by recurrent episodes of binge eating followed by vomiting or other methods to prevent weight gain. It's more likely to occur in the later teenage years. The bulimic individual is usually of normal weight, unless the bulimia is also accompanied by anorexia, an eating disorder involving severe, chronic weight loss.

Like obesity, bulimia stems from having poor eating habits, getting too little exercise and living in a world where the media decides whom we should admire. Peer pressure from friends plays a large role in the development of bulimia in girls--you rarely get bulimia in a boy. (In general, boys are not as conscious of their appearance as girls are.)

Girls are more mature and more social creatures, which means they are more likely to fall into the trap of needing to fit in with their peers.

Bulimia is a psychological problem with potentially serious health effects. It affects one percent of all teenagers. Binge eating followed by vomiting causes a loss of electrolytes (sodium, potassium, and chloride), a loss of nutrients, a loss of fluids, and a loss of body mass. So your body is in a malnourished state, and that impacts your immune system, allowing you to become susceptible to all sorts of viral infections.

The continuous vomiting can alter the mechanics of your heart, kidneys and liver. Bulimia is like putting a dollar of gas in your car's gas tank and running on empty all of the time. You are always sucking the bottom of the tank, the carburetor is getting full of suds, and you are constantly at risk of running out of gas. Ultimately, the bulimic individual faces the equivalent of stopping in the middle of the highway and having a major accident.

Since bulimics tend to be of average weight, it is difficult to recognize bulimic individuals simply by looking at their appearance, but a careful observer can learn to read the hidden signs of the disease.

The Hidden Signs of Bulimia

--Bulimics tend to have low self-esteem and may be depressed

--They often have difficulty expressing their emotions

--They seem to consume large amounts of food with no change in weight

--They have odd eating behaviors and tend to eat alone

--They are secretive about the time period after eating or have complex lifestyle schedules to make time for their binge-and-purge sessions

--They are preoccupied with their body image and may wear baggy clothes.

--They have an excessive an rigid exercise routine.

--They have callused or colored finger joints or backs of the hands from jamming their fingers down their throats to induce vomiting.

--They have discolored or decalcified teeth and swollen or bleeding cheeks and gums, caused both by vitamin deficiencies and the stomach acid that comes up with vomit.

Recovering From Bulimia

Recovery from bulimia requires treatment, lifestyle changes, and the resolution of the underlying psychological and social issues that triggered the problem. To identify these issues, solve the problems, and overcome the fears, psychotherapy is an essential ingredient in the treatment of bulimia. Nutritional counseling is also often necessary to restore physical health, and a doctor can prescribe drugs to help reduce the binging and purging of bulimia, as well as treat the depression and anxiety that often accompanies it.

Bulimia is a difficult problem to tackle, because, again, the media has such a significant influence on our lives. Just at the age when teenagers are trying to develop a personal identity and body image, the entertainment industry creates within them a desiere to be the most popular, the prettiest, the thinnest. Everything today is targeted to popularity and good looks, especially for teenagers. That is the message the media dishes out every day. When unchecked by parents and a supportive home life, adolescent children exposed to that constatnt message can end up believing that being thin is what's most important in life and that everything else will follow.

Most girls who are bulimic are also depressed. Why depresion? Because they never feel that they have achieved their goal. They never feel popular enough, pretty enough, thin enough. Their ideal body image always lies just over the horizon. It's an illusion with dire consequences.

Anorexia

Compared to the bulimic individual, the person with the eating disorder called anorexia norvosa is an easy read. Anorexics, as they are known, weight 85 percent or less of what a normal person of their age and height usually weighs. Anorexics have an absolute fear of becoming fat and, in fact, believe they are fat even though they are very thin.

Rather than regurgitating what they eat like bulimics, anorexics simply reduce how much they eat, often to fewer than a thousand calories per day. As a result, their nails, hair and bones become brittle; their skin may become dry and yellow; and they become depressed and often complain of being cold.

In young girls, menstruation is delayed, and in women, menstrual periods stop. Eventually, the lack of nutrition will damage the heart and brain.

Anorexia nervosa predominately affects adolescent girls and young adult women, although it can also occur in men and older rwomen. About 0.5 to 1 percent of females in the United States become anorexic.

As with bulimia, treatment for anorexia requires psychotherapy to deal with the underlying emotional issues. The complications associated with anorexia are reversible once their weight is restored. A weight gain of one to three pounds a week is considered safe. Obviously, the sooner the problem is recognized and treated, the better.

Click here to check out Dr. Manny's book The Check List (Harper Collins, 2007).

Dr. Manny Alvarez is the managing editor of health news at FOXNews.com, and is a regular medical contributor on the FOX News Channel. He is chairman of the Department of Obstetrics and Gynecology and Reproductive Science at Hackensack University Medical Center in New Jersey. Additionally, Alvarez is Adjunct Professor of Obstetrics and Gynecology at New York University School of Medicine in New York City.

Dr. Manny Alvarez serves as Fox News Channel's senior managing health editor. He also serves as chairman of the department of obstetrics/gynecology and reproductive science at Hackensack University Medical Center in New Jersey. Click here for more information on Dr. Manny's work with Hackensack University Medical Center. Visit AskDrManny.com for more.