Atypical Anorexia Nervosa: Symptoms, Risks, Diagnosis, and Treatment

Atypical anorexia nervosa is a type of restrictive eating disorder classified in the DSM-5 under the Other Specified Feeding or Eating Disorder (OSFED) category. Atypical anorexia nervosa and anorexia nervosa share the same symptoms, but with one exception – in atypical anorexia nervosa, the person is not underweight. Since someone who suffers from atypical anorexia nervosa is at a weight that is average or above average, the illness is often missed by health care providers. Despite the potential for serious, and even fatal, complications from this eating disorder, many people do not think they are sick enough to need treatment.

What is Atypical Anorexia Nervosa?

Someone who suffers from atypical anorexia nervosa may have a history of living in a larger body. At some point, they become so preoccupied with negative thoughts about their weight or shape, they start restricting calories. This may lead to a significant amount of weight loss, but their weight is still in a range that is considered “healthy.” For example, let’s say there was a person who was usually around the 95th percentile for their weight. They started to become very concerned about their body size, began to eat a lot less, and dropped to the 50th percentile. This person would be in danger of all the same health risks as anorexia nervosa, but would not meet the significantly underweight criteria. They would be diagnosed with atypical anorexia nervosa instead. Knowing someone’s weight history can be an important part of recognizing this illness. All weight loss is not necessarily good. In this example, dropping from the 95th to 50th weight percentiles could lead to serious medical and psychological complications. A person with atypical anorexia may not have noticeable physical symptoms, but it is still a life-threatening disorder.

Atypical Anorexia Nervosa Diagnostic Criteria

There are three main criteria to consider when diagnosing someone with atypical anorexia nervosa:

• severe restriction of food intake, and/or other behaviors such as purging or increased exercise
• intense fear of weight gain or persistent behaviors that interfere with weight gain
• distortion or dissatisfaction with body size, weight or shape in a way that affects self-worth

These same criteria are used to diagnose anorexia nervosa, except in atypical anorexia nervosa the person is at or above a normal weight range at the time of diagnosis.

Epidemiology and Prevalence

Atypical anorexia nervosa is as common, or even more common, than anorexia nervosa. Studies indicate that 0.2-4.9% of people will experience atypical anorexia nervosa in their lifetime. The peak onset for atypical anorexia nervosa is around 18-29 years old. One study of young women found the lifetime prevalence rate by age 20 was 2.8% for atypical anorexia nervosa compared to 0.8% for typical anorexia nervosa. Although more people suffer from

atypical anorexia nervosa, they are less likely to receive eating disorder treatment.

Atypical Anorexia Nervosa vs. Typical Anorexia Nervosa

Although both illnesses can include a drive to lose weight at any cost, an intense fear of being in a larger body and restrictive eating behaviors, someone diagnosed with atypical anorexia nervosa will not appear to be visibly emaciated. Since the weight loss may be less noticeable, providers may not recommend eating disorder treatment. Individuals who struggle with an eating disorder in a larger body are often ignored or dismissed.

Signs and Symptoms of Atypical Anorexia Nervosa

• Eating significantly reduced portions or skipping meals
• Avoiding certain foods or food groups
• Being overly focused on nutritional facts
• Finding reasons not to eat
• Excessive or rigid exercise regimen
• Preoccupation with body shape or size
• Frequent weighing and checking image in mirrors
• Binge eating and/or purging
• Fatigue and/or dizziness
• Trouble concentrating
• Insomnia

Emotional and Social Signs

Someone with atypical anorexia may become isolative, irritable or moody. They may become secretive and stop participating in previously pleasurable activities. As the obsessions about food, weight and body image worsen, individuals are at increased risk for other mental health issues such as anxiety, depression and suicidal thoughts. One study showed that while individuals with anorexia nervosa have lower body weights, those with atypical anorexia nervosa experience greater levels of functional impairment and emotional distress.

Physical Symptoms and Complications

Malnutrition from eating disorders can occur at all body weights.  Furthermore, the medical condition of individuals with atypical anorexia nervosa can be as bad or even worse than those with anorexia nervosa. Some health consequences of atypical anorexia nervosa include:

• Digestive issues, feeling cold all the time, dry skin, hair loss
• Low heart rate and low blood pressure, abnormal heart rhythms
• Stunted growth
• Loss of periods and infertility
• Loss of bone mineral density, risk of increased fractures
• Electrolyte abnormalities, such as low phosphorus, potassium and sodium
• Low white or red blood cell count
• Passing out, seizures

Comorbid Mental Health Conditions

Someone who already struggles with a mental health condition has a higher risk of developing an eating disorder. Co-occurring conditions include Major Depressive Disorder, Bipolar Disorder, Substance Use Disorder, and any type of anxiety disorder such as Generalized Anxiety Disorder, Social Anxiety or Post-Traumatic Stress Disorder. Atypical anorexia nervosa is associated with increased self-injurious behaviors, such as cutting, and suicidal thoughts. Given the serious psychological and medical risks to individuals with atypical anorexia nervosa, it is important to seek help from an eating disorder professional as soon as possible.

Demographic and Social Risk Factors

Many individuals with atypical anorexia nervosa were teased about their weight as children and were overweight at some point in their lives. Exposure to repeated messages about diets or labeling foods as “good” or “bad” can lead to restrictive eating and a higher risk of developing an eating disorder. And while playing sports can be positive in many ways, it can also increase the risk for an eating disorder through excessive exercise and calorie deficits. Some athletes focus on lean physiques or attempt to lose weight to improve performance despite the potential health complications. Finally, individuals who identify as LGBTQ+ experience higher rates of eating disorders, including atypical anorexia nervosa. Transgender and gender minority individuals are at particularly high risk, and report the highest rates of eating disorder symptoms across all groups.

Environmental and Cultural Influences

We live in a society that can focus on the “thin ideal,” leading one to engage in behaviors to lose weight at any cost. High school students who use social media more than two hours per day reported more body image issues than those who use social media less frequently. Mass media often promote thin and muscular images and permit deceptive or false advertising for weight loss. This culture of diet, weight loss and pressures on one’s appearance can lead to disordered eating, which can progress to the restrictive behaviors seen in atypical anorexia nervosa. Despite the dangers of severely limiting food intake, a person with atypical anorexia nervosa may receive compliments about their weight loss, which only encourages the harmful behaviors to continue.

Biological and Genetic Factors

Although there are many factors that may contribute to developing atypical anorexia nervosa, we know that a family history of any eating disorder increases the risk of developing an eating disorder. Additional factors that may contribute to atypical anorexia nervosa are specific genes involved in appetite regulation and a history of living at a higher weight. An individual’s genetic makeup may cause them to need to significantly reduce intake in order to lose weight or maintain a lower weight. This alteration of their natural body weight can lead to even more disordered eating behaviors.

Conclusion: Hope and Healing from Atypical Anorexia Nervosa

Although atypical anorexia nervosa is a severe and often overlooked eating disorder, we know many of the physical and psychological symptoms can resolve with treatment. Early diagnosis and referral to comprehensive, multidisciplinary care can increase the chances of a successful recovery. Individuals with atypical anorexia nervosa may need medical monitoring and support from eating disorder professionals to normalize eating, stabilize weight and address any co-occurring mental health concerns. Family support to seek help and continue treatment – regardless of weight or appearance – can make a significant difference in someone getting the care they need and deserve. If you or someone you love have concerns about eating, weight or body image, please reach out for help today.

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