What is Atypical Anorexia?

Atypical anorexia (AAN) was added to the Diagnostic and Statistical Manual-5 as a type of Other Specified Feeding and Eating Disorder (OSFED) in 2013. It is diagnosed when a person meets all of the criteria for anorexia nervosa, “except that despite significant weight loss, the individual’s weight is within or above the normal range.” A person with AAN still meets the other criteria for anorexia nervosa (AN): fear of gaining weight or becoming fat, body image disturbance, and presenting with “significant weight loss.” This can occur because these patients start out in higher weight categories. However, based on their trajectory of weight loss and restrictive behaviors, they are actually in a state of malnourishment, much the same as patients with AN. “Significant weight loss” lacks a widely accepted definition. Research suggests that when combined with the intense fear of weight gain or fat and significant body image disturbance experiences, as little as a 5 percent weight loss may indicate clinically meaningful eating pathology, qualifying the patient as having a diagnosis of atypical anorexia nervosa.

Speaking With a Doctor

Eating disorder therapists may often see individuals at weights that would usually be considered “normal” but who have had restrictive eating disorders, complete with amenorrhea (missed menstrual periods), which can be a common side effect from a reduction from ideal body weight. However, many doctors unfortunately never consider that amenorrhea in a higher weight individual could be due to dietary restriction. If you or a loved one is struggling with anorexia or side effects from any eating disorder, be sure to speak to a doctor or a healthcare professional. Often, side effects can develop into severe medical conditions on their own.

Research on Atypical Anorexia

Lebow and colleagues reviewed 179 intake evaluations for adolescents who presented for eating disorder evaluations at the Mayo Clinic. All adolescents were seeking help for a restrictive eating disorder, characterized by weight loss and/or dietary restriction. The findings revealed that those with a history of being overweight, when compared to individuals without this history: There was an error. Please try again.

Presented with a weight status in a range traditionally considered “healthy” (BMI between 18.5 and 24.9) at the time of seeking treatmentHad experienced a greater drop in BMIHad been ill for about 10 months longerHad eating disorders that were just as severe in terms of common symptoms, rates of amenorrhea, and the number of reported physical symptoms.

Though some adolescents and children (and likely even adults too) may appear to be at healthy or normal weights, if they are experiencing an eating disorder or disordered eating, they can be significantly physically or emotionally impaired. Research has demonstrated that patients who lost a larger percentage of their baseline BMI had medical problems as serious as those of patients who presented at a lower BMI but who had lost less weight overall. There are significant implications to these findings:

Many serious eating disorders may go undetected because we have become too focused on absolute weights as barometers for health. Physical complications of semi-starvation and weight loss—red flags in a low-weight individual—are often overlooked in higher-weight patients. A BMI that falls into the higher weight categories is normal for some individuals. These people may need support from professionals in learning to accept a body weight that is higher than the culture at large considers desirable. Even in the absence of low weight, practitioners should remain attuned to physical consequences of malnutrition or eating-disordered thoughts and behavior. When assessing an individual with eating symptoms and/or weight loss, providers should consider an adult’s weight history (or in the case of an adolescent, the full developmental growth curve) rather than a single data point. Individuals with a history of being overweight can suffer from an eating disorder for longer before it is identified. Given that early identification is the best predictor of full recovery from an eating disorder, greater attention needs to be paid to this population.

Both in health care settings and society at large, a larger individual’s weight loss is often seen as a positive. However, it may place the person of higher weight at risk for developing a restrictive eating disorder. In general, science supports that extreme dieting should be discouraged. Furthermore and most fundamentally, it is important to remember that eating disorders can happen to a person at any weight.