Anorexia nervosa is an unusually deadly mental disorder centered on a fixation with thinness and weight loss. Current guidelines allow doctors to diagnose the disorder in individuals whose body weight falls below 85 percent of expected norms. However, according to the results of a new report published in September 2013 in the American Academy of Pediatrics journal Pediatrics, significant numbers of teenagers affected by anorexia actually begin to participate in disordered eating patterns while heavy enough to qualify for a diagnosis of obesity. Because they don\u2019t \u201clook\u201d anorexic, or meet official anorexia guidelines, these teens often don\u2019t get the help they need for extended periods of time. Anorexia Basics Anorexia occurs primarily in girls and women, and tends to begin at some point during adolescence. As a rule, affected individuals lose the ability to accurately assess their weight and body shape, see themselves as \u201cfat\u201d even when their weight falls far below healthy levels, and adopt eating patterns that strictly limit the intake of calories and strongly reduce any chances for significant weight gain. Some people with the disorder augment their restrictive eating with behaviors such as laxative abuse, diuretic abuse or extreme exercising. In addition, some anorexics periodically engage in the binging and purging behaviors typically associated with another eating disorder called bulimia nervosa. Anorexia, bulimia and other diagnosable eating disorders produce a higher rate of fatality than any other form of mental disorder. In the case of anorexia, the potential for death arises because an anorexic eating pattern steadily robs the body of the nutrients it needs to maintain ongoing health and well-being. Eventually, people with untreated cases of the disorder develop symptoms of malnutrition and start to experience serious alterations in the normal function of vital organs such as the heart, kidneys and brain. Severe problems with heart function are especially prominent in advanced cases of anorexia and account for many fatal outcomes. Obesity Basics Doctors typically diagnose obesity with the help of a body fat-measuring formula called the body mass index (BMI), which uses weight and height calculations to place an individual on a scale of potential weight outcomes known as the BMI scale. Underweight people fall at the lower end of this scale, while normal weight people fall between the underweight range and a third classification called the overweight range. There are two classifications above the overweight range on the BMI scale: obesity and extreme (or morbid) obesity. People who fall into the obese or extremely obese ranges carry enough excess body weight to substantially increase their ongoing risks for a host of potentially deadly health problems, including heart disease, high cholesterol, type 2 diabetes, strokes, liver disease and some forms of cancer. Up to 20 percent of U.S. teens and younger children meet the standard definition for obesity or extreme obesity. Current Findings In the report published in Pediatrics, researchers from the Mayo Clinic presented preliminary evidence regarding the frequency of anorexia in obese teenagers, and also looked at the ways in which the presence of obesity can alter or delay the course of anorexia treatment. They undertook their efforts, in part, because doctors commonly associate obesity with the eating disorders bulimia and binge-eating disorder, but not with anorexia (which, under current guidelines, cannot be officially diagnosed in someone who qualifies for an obese, extremely obese, overweight or normal weight BMI classification). After reviewing the patient histories of teenage participants in Mayo Clinic anorexia programs, the researchers concluded that roughly 35 percent of these participants originally established their anorexic eating patterns while obese. The researchers also found evidence from prior studies that indicates that as many as 50 percent of teenagers affected by anorexia may exhibit the first symptoms of the disorder while obese or extremely obese. In addition, they concluded that the average obese teenager with anorexia symptoms may suffer from the effects of those symptoms for close to a year before his or her weight levels fall enough to meet the standards for an official anorexia diagnosis. Significance and Considerations The authors of the report in Pediatrics note that anorexia guidelines from an earlier era allowed doctors to diagnose the disorder in anyone who lost more than 25 percent of their body weight, whether or not this weight loss left them with an underweight BMI classification. They believe that the current restriction against diagnosing anorexia in anyone who is not significantly underweight leaves substantial numbers of obese teenagers without official recognition or access to appropriate treatment. This lack of access amounts to a treatment delay that may seriously and negatively impact the long-term health outcomes of affected teens.