Atypical anorexia diagnosis? Handle with care!

What is atypical anorexia?

Has your child been diagnosed with 'atypical' anorexia nervosa?

Discovering your child has an eating disorder is a shock, so first I want to reassure you: an expert in eating disorders should deliver excellent treatment towards complete recovery.

Have a read, and if you're not sure your child is getting competent treatment for atypical anorexia nervosa, this page guides you to ask important questions.

Atypical anorexia: 'Your weight is normal'

Atypical anorexia nervosa is one of the diagnostic categories in the DSM-5 diagnostic manual. Put simply, it's the same as anorexia nervosa except that right now, the person doesn't look horribly thin.

I'll show you how that can, in places, give a false sense of safety and lead to poor treatment and poor recovery. That way you can make sure your child gets great treatment. Indeed in the UK, the NICE guidance recommend that atypical anorexia follows the same treatment guidelines as for anorexia.

"The child who normally grows on the 90th percentile and now suddenly is found on the 70th percentile will be just as sick as a child who started on the 10th and fell to below the 3rd.

But such a child will often be told, "Well, this is actually an improvement. You were overweight before and now you're approaching normal."

This is a catastrophe. And if somebody tries to tell you that or worse, tell your child that, you know, you need to seek another opinion."

Dr Julie O'Toole in YouTube (2025) "What constitutes good medical care"

Criteria for anorexia and for atypical anorexia nervosa

For a diagnosis of anorexia nervosa:

one of the criteria is :

"Restriction of energy intake relative to requirements, leading to a SIGNIFICANTLY LOW BODY WEIGHT in the context of age, sex, developmental trajectory and physical health. Significantly low weight is defined as a weight that is less than minimally normal or, for children and adolescents, less than that minimally expected."

DSM-5

For a diagnosis of atypical anorexia:

 “All of the criteria for anorexia nervosa are met, except that despite significant weight loss, the individual’s weight is within or above the normal range.”

DSM-5

So you see, it's all about 'normal' — normal today, right now.

Atypical anorexia nervosa is one of the OSFED categories in the DSM-5 diagnostic manual: ‘Other Specified Feeding or Eating Disorder

Atypical anorexia: common, and no less serious

Why do so many experts want the 'atypical' diagnosis to be scrapped?

• The term 'atypical anorexia' might make people think the eating disorder is … not typical. It might mean this field gets less attention. Yet atypical anorexia is very typical. It's more common than the illness diagnosed as anorexia nervosa.
  
• And 'atypical' makes it sound less serious, right? Yet it can be very serious, both physically and mentally. It needs treatment to the same standard, with the same level of expertise, as anorexia.
• On the other hand, maybe the 'atypical' category helps remind clinicians that someone currently with a normal or high BMI needs attention too.

What's considered a 'normal' weight in the definition of atypical anorexia?

The 'normal' range is what an internet calculator brings up when you plug in height, weight, sex and age.

So it's a statistical measure, not one relating to your child as an individual.

I have a very tall friend — the kind of guy who stoops to go through doorways. Clearly not 'normal' statistically. Imagine a scenario where one morning he wakes up realising he's shrunk to average height. There'd be a few investigations, right? Even though his height is now weirdly 'normal'.

All this to say, your child's needs are individual (I collected lots of quotes from top experts here) — statistics is for big populations studies. Sometimes statistics gives us a decent ballpark, but sometimes it's way off, as I show in this YouTube or on this page 'Is your child’s target weight a gift to the eating disorder? One-Size-Fits-All versus Growth Charts'.

Is 'the normal' weight range normal for YOUR child?

Did your child undergo 'significant weight loss'? Because that's part of the diagnosis for atypical anorexia. Perhaps it was actually an enormous amount? Did they lose it over years of restricting, or did they lose at an alarming speed?

And when you read the signs and symptoms of anorexia nervosa, the anxieties and distorted beliefs and obsessive behaviours, does that pretty much describe your child?

So your child will get the 'atypical anorexia' diagnosis, because their weight is not currently 'significantly low'. Even though it's terribly low for them as an individual.

How much weight loss is 'significant weight loss'?

'Significant weight loss' is not defined in the diagnosis for atypical anorexia nervosa.

You might for instance hear that because your child 'only' lost 5% of their weight, there is no cause for concern, and no diagnosis. Someone might make the additional point that your child is currently of 'normal' weight or more. However if your child is showing mental (cognitive) symptoms, there is evidence that even 'just' a 5% loss should raise alarm:

From a study by Forney et al (2017):

"Results support that even a 5% weight loss, combined with cognitive concerns, may produce a group with a clinically significant eating disorder. Atypical Anorexia Nervosa was observed in both healthy weight and overweight/obese adults, highlighting the importance of screening for restrictive eating disorders at all weights."

Forney et al (2017)

What emerges from this study is that weight suppression of 5% or more is associated with the mental signs and distress that are the hallmarks of an eating disorder. Note that the researchers did not look at levels below 5%, and that this was for adults.

In my page on weight suppression I show the example of a girl who stayed the same weight between ages 10 and 11. So she dropped off her percentile curve, which is a weight loss of 12%. If her body was due a growth spurt, the deficiency is even greater.

(Even though I show charts and numbers, please remember that with human growth, there are very few certainties, as explained here).

What about 'developmental trajectory'?

I get confused by the diagnostic manual. Because in the definition of anorexia, we have 'significantly low body weight in the context of […] developmental trajectory and physical health'. So if a child's BMI is currently 'normal' or higher for their age and sex, but it's shot down in terms of 'developmental trajectory' (such as failure to gain weight when you're a growing child) and if their physical health is poor, then personally I'd argue we have ticked the boxes for anorexia, as well as for atypical anorexia.

What about weight that — for children and adolescents — is 'less than that minimally expected'

Another thing that confuses me about the definition of anorexia nervosa, is that for children and adolescents, is includes weight that is 'less than that minimally expected'. Well, we expect children to grow and to keep tracking on their weight percentile curves. Any drop from that is less than expected. So a child who has lost weight doesn't need the 'atypical' diagnosis. It's anorexia.

What's the problem, if the person isn't emaciated?

The problem is in the amount and speed of weight loss. Your child's nutrition, metabolism, the whole amazing way a body regulates hormones and nutrients — all that will have been affected. You can't tell how badly by just looking at BMI. But you can and should report on the weight loss history, and any physical, mental and behavioural signs that concern you.

'You're fine because your BMI is fine'

When someone looks terribly thin, it's easy to guess there might be a problem. If they're not thin, it's easy to assume they're fine.

Irrespective of your child's current BMI — low, average or high — if there's been weight loss –especially rapid, major loss — and if your child's displaying the mental and behavioural signs of anorexia, clinicians should do a full medical and mental assessment.

A clinician can miss medical and mental risks when their only criterion their only criterion is BMI or weight-for-height. This really does happen.

It doesn't help, of course, that with an eating disorder our children can put on a GREAT show of health and happiness while talking with a clinician. Your own version might not be heard. As a result, a clinician might pronounce your child healthy, and not needing any further tests or treatment.

They may even praise your child for losing weight, as though that automatically makes someone healthy.

By now you probably know how toxic it is for your child to be praised for their obsessive weight loss, food restriction and over-exercising.

With expert clinicians, this won't happen, but there may still be a fight: people may be denied treatment via their medical insurance, or by the national health service… because they're not (yet) thin.

"I am fine!"

People with anorexia tend not to recognise they have a problem. It's called 'anosognosia' and it's part of the glitch in the brain. Also, they get short-term soothing from their behaviours (the illness is 'egosyntonic').

When these individuals see their weight is 'normal' or higher, they're even less likely to recognise that they have anorexia. 'Hey, I'm hardly thin! AI says my BMI is healthy! AI analysed images of my body and says I have an athlete's body, yay!' So they don't look for eating-disorder help. Indeed what they're looking for is how to make their weight-loss diet 'more effective'.

And then sometimes a person with an eating disorder does consult a doctor, or gets dragged in by their parents, and too many leave with their distorted thoughts strengthened: 'I'm not thin enough to be ill, I'm not thin enough to get help'.

For all these reasons, parents, partners, friends and clinicians should recognise anorexia, irrespective of the person's current weight.

Atypical anorexia: rushed to hospital with a normal BMI

We parents know from experience how very ill our child can be from weight loss — and that is true with kids who look emaciated, and with kids who look average or large.

So if your child has lost a lot of weight, make sure they get proper medical checks. See for instance the MEED (Medical Emergencies in Eating Disorders) guidelines for the UK, and the AED 'purple booklet': Academy for Eating Disorders Guide for Medical Management of eating disorders for the US.

Of course, if someone's weight is very low, their body is probably malfunctioning. But the same medical attention is needed for those who have lost a considerable amount of weight. Here are some papers:

"the extent of physical compromise reported here in adolescents with atypical AN, who are by definition not underweight, suggests that beyond the effects of underweight, substantial loss of weight and/or rapid weight loss may itself be detrimental to physical health”

Sawyer, S. M., Whitelaw, M., Le Grange, D., Yeo, M., & Hughes, E. K. (2016). 'Physical and Psychological Morbidity in Adolescents With Atypical Anorexia Nervosa'. Pediatrics.

So it's not the current weight, but the weight history, that predicts physical risk:

"In adolescents with restrictive EDs, total weight loss and recent weight gain were better predictors than admission weight of many physical complications"

Whitelaw, M., Lee, K. J., Gilbertson, H., & Sawyer, S. M. (2018). 'Predictors of Complications in Anorexia Nervosa and Atypical Anorexia Nervosa: Degree of Underweight or Extent and Recency of Weight Loss?'. The Journal of adolescent health : official publication of the Society for Adolescent Medicine

This is echoed in this study of 12 to 24-year-olds:

"Patients with large, rapid, or long-duration of weight loss were more severely ill regardless of their current weight"

Garber, A. K., Cheng, J., Accurso, E. C., Adams, S. H., Buckelew, S. M., Kapphahn, C. J., Kreiter, A., Le Grange, D., Machen, V. I., Moscicki, A. B., Saffran, K., Sy, A. F., Wilson, L., & Golden, N. H. (2019). 'Weight Loss and Illness Severity in Adolescents With Atypical Anorexia Nervosa'

and as explained in an interview about the study:

"The study found that female atypical patients were just as likely as their underweight counterparts to stop menstruating, a hallmark of hormone suppression due to poor nutrition that impacts fertility and bone density. Both typical and atypical patients were susceptible to electrolyte imbalances […] which can impact the brain, muscles and heart functioning."

Mentally worse off

The above study highlighted another reason to take 'atypical' anorexia very seriously: the patients' mental state — their psychopathology:

"The reproducible finding that patients with Atypical Anorexia Nervosa have worse Eating Disorder psychopathology continues to dispel the misconception that AAN is a lesser illness than AN"

This emerged from scores in the Eating Disorder Examination Questionnaire, a tool that looks at 'avoidance of food and eating, preoccupation with calories and eating in secret, feelings of fatness and discomfort seeing one’s body, dissatisfaction with weight and reaction to being weighed'. The 'atypicals' scored significantly worse.

The treatment should be the same

When you get diagnosed with 'atypical' anorexia, you may get treated rather differently, because people aren't alarmed about your weight, even though they should be.

For example, adults with atypical anorexia, after spending time in residential treatment, may report being fed smaller portions than people with anorexia. Recovering lost weight was not on the agenda, and this confirmed their belief that eating-disorder behaviours are only frowned upon if you're skin and bones.

However, the NICE guidelines for eating disorders (these are official guidelines for England, based on in-depth reviews of the evidence) require any OSFED (‘Other Specified Feeding or Eating Disorder’), including atypical anorexia, to be treated the same as the illness they most resemble.

In other words, we have to treat atypical anorexia the same as anorexia and not let current body shape lure us into complacency. I look forward to the day those guidelines are followed everywhere and this page becomes unnecessary.

Regaining weight

After big, rapid weight loss, make sure your child gets a full medical assessment. From that, there should be a plan for nutritional rehabilitation — and that could well include regaining some, or much, or all of the lost weight.

To my knowledge there is no research to give a blanket answer to 'how much'? Your child deserves individual, specialist assessment and monitoring, and the 'how much' question can probably not be reliably answered right away.

Our children can get very focused on weight, and as parents we need to find some peace around all the uncertainties. When the person's weight was particularly high before it started dropping, it's especially important that as a parent, you should feel safe and heard in your weight discussions with clinicians. The same if you're posing questions in parent support groups. For more on the many factors that are considered in estimating how much weight gain your child might need, see my page 'Weight-restoration: why and how much weight gain?

Onwards

The following pages of mine will help you understand how clinicians may be setting weight targets, and the rationales — good and bad.

My main page on weight restoration
* Weight-restoration: why and how much weight gain? *

and also:
* Experts say, "Recovery weight must be individualized" *
* How much weight did your child lose? Weight suppression is critical in eating disorder diagnosis and treatment *
* Weight gain in growth spurts *
* Weight centile growth charts: why they can’t predict your child’s recovery weight *
* My YouTube: Growth charts and goal weights made simple *
* Is your child's target weight a gift to the eating disorder? *
* What do BMI and Weight-For-Height mean? *
* My YouTube: What is a BMI or '% Weight-for-Height' target, and how wrong it could be *

And more:

* More on weight and feeding in Chapter 6 of my book and in my Bitesize audio collection *

More reading on atypical anorexia

Lauren Muhlheim's concise overview: Help for Atypical Anorexia: https://www.eatingdisordertherapyla.com/help-for-atypical-anorexia/

and When Eating Disorder Providers Are Steeped in Diet Culture:https://www.eatingdisordertherapyla.com/when-eating-disorder-providers-are-steeped-in-diet-culture/

Walsh, B. T., Hagan, K. E., & Lockwood, C. (2022). A systematic review comparing atypical anorexia nervosa and anorexia nervosa. International Journal of Eating Disorders, 1– 23. https://doi.org/10.1002/eat.23856

Golden, N. H. (2022). Atypical Anorexia Nervosa is not atypical at all! Commentary on Walsh et al. (2022). International Journal of Eating Disorders, 1– 2. https://doi.org/10.1002/eat.23871

Harrop, E. N. (2022). A lived experience perspective on the classification of atypical anorexia nervosa. International Journal of Eating Disorders, 1– 2. https://doi.org/10.1002/eat.23884