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What is OSFED?

Written by Emily Green

what is OSFED?

The narrow diagnostic criteria for eating disorders (EDs) are evidence-based, informative and necessary.

But what happens when you’re struggling with eating issues that don’t fit neatly into the common categories of anorexia nervosa (AN), bulimia nervosa (BN) or binge eating disorder (BED)?

Other Specified Feeding or Eating Disorder (OSFED) is a different eating disorder diagnosis that you might have never heard of. Previously called EDNOS (Eating Disorder Not Otherwise Specified), OSFED is an umbrella term for several clinical presentations of feeding or eating disorders which do not fit precisely into the criteria for typical diagnoses such as AN, BN or BED.

Potentially the most important thing to note is that just because some diagnoses which fall under OSFED can be termed ‘atypical’ or ‘subthreshold’ does not mean the illness is any less severe, distressing or clinically important. Anyone struggling with OSFED is equally deserving of treatment and high quality care.

Prevalence of OSFED

To understand the health challenges we face, the Global Burden of Disease (1) assesses diseases, injuries and risk factors to quantify health loss. Anorexia and bulimia nervosa are the only EDs included in this assessment as they are most commonly included in empirical research. However, we know that these are not the only serious eating disorders or the most common.

A study published in The Lancet Psychiatry recognised this and aimed to quantify binge eating disorder and OSFED (2). They reported OSFED prevalence at 24.6 million cases globally compared to 55.5 million total cases of eating disorders in 2019. That’s 44% of known cases of eating disorders.

After accounting for 17.3 million with BED, that leaves only 13.6 million cases of other eating disorders such as AN and BN. This shows just how important it is to have good quality research into eating disorders.

Breaking Down The Diagnosis of OSFED

To categorise OSFED, healthcare practitioners will look for symptoms characteristic of eating disorders which cause significant clinical distress, social impairment or disruption to normal life (e.g. occupation or relationships) but DO NOT completely meet the criteria for the diagnostic class of feeding and eating disorders (3).

OSFED, as the umbrella term includes:

1. Atypical Anorexia Nervosa

2. Bulimia Nervosa (subthreshold)

3. Binge Eating Disorder (subthreshold)

4. Purging Disorder

5. Night Eating Syndrome

6. Orthorexia (not yet officially recognised)

OSFED diagnosis

The relevant sub category is usually specified, so if someone is to be diagnosed with OSFED it could be recorded as:

e.g. "other specified feeding or eating disorder, bulimia nervosa - low frequency"

The symptoms and experience of people diagnosed with OSFED are not so clear cut meaning that each person will likely present differently, even with the same recorded diagnosis.

Let’s look at a few examples of OSFED subcategories from the Diagnostic and Statistical Manual of Mental Disorders (DSM-V) (3):

Atypical Anorexia Nervosa

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. Atypical anorexia nervosa should still be treated just as seriously, regardless of BMI.

*Please note that a "normal" BMI range as published on the NHS website is 18.5-25. Here are our thoughts about The Truth About BMI and What is a Healthy Weight? which we're covered in previous blogs.

Bulimia Nervosa (of low frequency and/or limited duration)

All of the criteria for bulimia nervosa are met, except that the binge eating and inappropriate compensatory behaviours occur, on average, less than once a week and/or for less than 3 months.

Binge-eating disorder (of low frequency and/or limited duration)

All of the criteria for binge-eating disorder are met, except that the binge occurs, on average, less than once a week and/or for less than 3 months. For cases where frequency and duration criteria are met, our blog What Is Binge Eating Disorder? explains this diagnosis in detail.

Purging disorder

Recurrent purging behaviour to influence weight or shape (e.g. self-induced vomiting; misuse of laxatives, diuretics, or other medications) in the absence of binge eating.

Night eating syndrome

Recurrent episodes of night eating, as manifested by:

  • Eating after awakening from sleep or by excessive food consumption after the evening meal.

  • An awareness of recall of the eating episode/s.

  • Not better explained by external influences such as changes in their sleep wake cycle or by local social norms.

  • Causes significant distress and/or impairment in functioning.

  • Not better explained by BED, another mental disorder, substance use, a medical disorder or an effect of medication.

We cover What is Night Eating Syndrome? in more detail in a separate post.


Orthorexia is derived from the words “ortho” meaning 'straight' or 'correct' plus “orexia” which is the Greek word for appetite.

It is not currently recognised in the DSM-V but there are separate diagnostic questionnaires. With influences from perfectionism, low self-esteem and obsessive self-improvement (4), it has similarities to AN but is characterised by an obsessive focus on ‘clean’ or ‘pure’ foods and strong ties to morality in eating. You can read more about Orthorexia in our blog, What is Orthorexia?

Barriers To Seeking Treatment

In our experience, some of the most common reasons why people don’t seek help for eating issues, especially OSFED include:

“I’m not sick enough”

When your eating disorder self can underplay just how much engaging in restrictive eating and/or compensatory behaviours impacts your life. Not feeling sick enough is a symptom of having an eating disorder. At TCN, we believe that if your eating difficulties are impacting your life in any way, that is enough of a reason to seek support.

“I’m not thin enough”

Weight suppression (even if still ‘technically’ within a healthy weight range) can cause serious psychological and physical consequences, such as fainting, dizziness and heart palpitations (5). Due to the high demand on NHS eating disorder services in the UK, many which use BMI as referral and admission criteria, we unfortunately see many people miss out on accessing public services and early intervention. Some reasons for this might be because they are turned away and feel unworthy to fight again to receive help or because they aren't underweight they don't feel that they will be taken seriously. Please don't ever give up hope.

“I don’t have a “real” eating disorder”

OSFED is actually the most commonly diagnosed eating disorder making up approximately 44% of all eating disorder diagnoses (2). Any eating difficulties that detrimentally impact your life are real, valid and deserving of treatment. Sometimes receiving an eating disorder diagnosis other than AN or BN can leave people feeling like they don't deserve help or their eating challenges aren't severe enough to warrant support, but this is not true.

If any of the eating difficulties detailed in this blog resonate with and apply to you, please contact your GP or get in touch with us directly for specialist support with the TC Nutrition clinic and complete an enquiry form to get in touch with our team.

Emily Green

TCN Intern

Emily Green

Emily is studying MSc Clinical Nutrition, after having graduated from a degree in Nutrition & Psychology from Newcastle University. She has an interest in supporting people to overcome disordered eating, find food freedom and keep a healthy mind. You can find Emily on Instagram @nutritionupontyne and on her blog



[1] IHME, 2019. Global Burden of Disease (GBD 2019). [online] Institute for Health Metrics and Evaluation. Available at: <> [Accessed 18 June 2022].

[2] Santomauro, D., Melen, S., Mitchison, D., Vos, T., Whiteford, H. and Ferrari, A., 2021. The hidden burden of eating disorders: an extension of estimates from the Global Burden of Disease Study 2019. The Lancet Psychiatry, [online] 8(4), pp.320-328. Available at: <> [Accessed 8 June 2022].

[3] DSM-V, 2013. Feeding and Eating Disorders. [online] DSM Library. Available at: <> [Accessed 10 June 2022]

[4] McGregor, R., n.d. Orthorexia - Renee McGregor. [online] Renee McGregor. Available at: <> [Accessed 15 June 2022].

[5] Sawyer, S., Whitelaw, M., Le Grange, D., Yeo, M. and Hughes, E., 2016. Physical and Psychological Morbidity in Adolescents With Atypical Anorexia Nervosa. Pediatrics, [online] 137(4). Available at: <> [Accessed 15 June 2022].


Talia Cecchele Nutrition is a team of registered dietitians that specialise in eating disorder recovery, disordered eating, sports nutrition and gut health. We aim to bring balance back to nutrition, help you to break free from food rules and find food freedom. We offer virtual consultations and group programs so whether you are based in London, the United Kingdom or around the world we would love to support you. To enquire about a private consultation please fill out a contact form.

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