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What is Bulimia Nervosa?

Written by Emily Green

what is bulimia nervosa?

Bulimia Nervosa (BN) is a pervasive, isolating mental illness which accounts for approximately 19% of eating disorder diagnoses (1). It is characterised by a cycle of binge eating and subsequent compensatory behaviours which are powered by intense feelings of guilt, anxiety and shame.

Who does Bulimia Nervosa effect?

Perhaps contrary to popular belief, eating disorders can affect anyone regardless of age, gender, socioeconomic status or ethnicity. Eating disorders are pervasive illnesses and do not discriminate.

The average age of onset for bulimia is 18-19yrs, slightly later than that of anorexia nervosa (3). It can affect individuals at any weight and those with the condition may not always appear underweight or unwell. Even if an individual is not clinically underweight, BN can still cause them to be weight suppressed, exhibit symptoms and suffer consequences from the illness (4).

For people in larger bodies there can actually be increased risks with suffering from an eating disorder. For example, delayed time to diagnosis and prevention of proper care due to weight stigma or practitioner’s implicit or explicit prejudices.

What Are The Causes of Bulimia Nervosa?

Research into the cause of eating disorders generally accepts there are many influences which are complex, interconnected and cannot be pinned down to one driving factor. It is likely a mixture of contributing psychological, environmental and biological influences.

A paper by Hay and Mitchinson summarised these influences and found several factors which did and did not contribute to development of an eating disorder. Notably, certain genetic factors, being female, younger age, participation in ‘lean’ sports (dance, gymnastics, swimming) and being a victim of abuse were found to increase the risk of onset. Whilst ethnicity, socioeconomic status, general sport participation, education level and urban or rural residence did not significantly affect the risk. To learn more, we cover Ethnic Diversity in Eating Disorders here in more detail.

what is bulimia nervosa

Some studies have explored a connection between specific genes and the dopamine or serotonin pathways which are relevant to mood or psychological characteristics present in eating disorders (5). Others have attempted to assess heritability of bulimia nervosa with estimates of 54-83% (6). However, this area of research is still ongoing and not yet reliably conclusive.

The important thing to remember is that being at an increased risk of developing an eating disorder does not necessarily mean you will. Risk factors and genetics do not predict a definite trajectory.

How is Bulimia Nervosa Diagnosed?

In the Diagnostic and Statistical Manual of Mental Disorders (DSM-V) (2), BN is defined according to five criteria and indicates severity by the frequency of inappropriate compensatory behaviours.

Typical bulimia nervosa is diagnosed when the following criteria are met:

A. Recurrent episodes of binge eating. An episode of binge eating is characterised by both:

1. Eating in a discrete period of time (e.g. within any 2 hour period), an amount of food that is definitely larger than what most individuals would eat in a similar period of time under similar circumstances;

2. A sense of lack of control over eating during the episodes (e.g. a feeling that one cannot stop eating or control what or how much one is eating.

B. Recurrent inappropriate compensatory behaviours to prevent weight gain, such as self-induced vomiting; misuse of laxatives, diuretics, or other medications; fasting; or excessive exercise.

C. The binge eating and inappropriate compensatory behaviours both occur, on average, at least once a week for 3 months.

D. Self-evaluation is unduly influenced by body shape and weight.

E. The disturbance does not occur exclusively during episodes of anorexia nervosa.

In the DSM-V, severity is assessed by the average number of inappropriate compensatory behaviours per week:

Mild: 1-3 episodes per week.

Moderate: 4-7 episodes per week.

Severe: 8-13 episodes per week.

Extreme: 14 or more episodes per week.

Are There Different Types of Binges?

Binge eating can be categorised into two types; objective and subjective. All binges are perceived as ‘too much’ food or excessive by the individual experiencing them but the actual quantity of food can differ. Binge eating is also a key characteristic of other eating disorders, mainly binge eating disorder.

Objective binge: the amount of food eaten during these binges are larger than a typical amount of food eaten in the same time period.

Subjective binge: this amount of food may not objectively seem like a large amount, but it is perceived as a binge by the individual. This is based on their beliefs and perceptions around how much food is too much for them. For example, a person might eat one sandwich and consider it a binge, despite this being a normal portion for most people.

Binge Eating vs Overeating?

Overeating is distinct from binge eating as it is not accompanied by the same inappropriate compensatory behaviours.

Overeating is a normal behaviour that can affect anyone from time to time and it’s not always negative - think about celebrations where you might have an extra slice of birthday cake even if you weren’t physically hungry. Eating past the point of comfortable fullness can also occur due to emotional hunger when food is a comfort to soothe difficult emotions, or boredom. Learn how to identify emotional hunger in our blog post, Why Do I Feel Hungry?

Binge eating differs in that it is accompanied by a lack of control or marked distress, guilt or shame at oneself after eating. With both overeating and binge eating, an issue may arise when this way of eating becomes an individual’s main coping mechanism for emotional regulation or distress, or as an act of self harm.

In our current society, the word "binge" has been adopted as an adjective to describe any activity done to excess. We say we binge watch Netflix and binge drink alcohol, but does this diminish the seriousness of a binge associated with eating disorders? The psychological aspects of binge eating like intense negative feelings, anxiety or dissociation are what set it apart as a diagnosable behaviour.

Warning Signs of Bulimia Nervosa:

The nature of eating disorders often means signs and symptoms will be hidden due to secrecy, shame, or not being ready to recover. However, there are some red flags to look out for which can show up in eating behaviours, thoughts and beliefs, physical health or emotional disturbances.

  • Eating in secret

  • Intense anxiety around food and eating

  • Regularly weighing themselves

  • Leaving the table straight after meals

  • Social withdrawal and isolation

  • Evidence of empty packets or food missing from cupboards

  • Excessive or compulsive exercise for weight loss not enjoyment

  • Hoarding or hiding food

  • Body checking, skin pinching, looking in mirrors

  • Absence of menstruation

The Dangers of Purging Behaviours

Those who suffer with bulimia will purge in order to compensate for the food eaten during a binge. This can involve self-induced vomiting to try and prevent nutrition from being absorbed, abuse of laxatives or diuretics to ‘flush out’ the digestive system, or excessive exercise as an attempt to expend more calories than have been consumed.

This cyclical pattern of behaviour leads to many physical issues as well as the perpetuation of bulimia symptoms and thinking patterns

Physical dangers of purging include:

  • Digestive issues - acid reflux, heartburn, constipation, stomach pain and bloating

  • Dental erosion from stomach acid

  • Heart problems

  • Electrolyte imbalances such as low potassium or sodium

  • Fluctuating weight

  • Absent or irregular menstrual cycle

  • Sores on the back of hands

  • Swollen glands

  • Feeling light-headed, dizzy or fainting

  • Oesophageal bleeding or rupture

  • Severe dehydration

What to Expect in Treatment for Bulimia Nervosa?

Treatment is a long-term process to restore physical and mental health, and address the factors maintaining the eating disorder. Eating disorders are complex conditions, so treatment should always involve a multi-disciplinary team. Typically, the first point of contact is your GP who will refer you onto a specialist team including a psychological professional and registered dietitian.

Guided self-help

For adults, this is often the first treatment step and involves working through a structured self-help book alongside sessions with a healthcare professional. This may help you become aware of your disordered behaviours and triggers, establish regular meals and develop healthier coping mechanisms.

Cognitive Behavioural Therapy (CBT)

With support from a therapist, CBT works towards increasing your awareness of and challenging unhelpful thought patterns and behaviours relating to your eating disorder.

Family Therapy

This can be offered to children and young people as a way to integrate the family into their recovery and build a network of support at home.


Alongside therapy, taking prescribed medication can be helpful in managing psychological symptoms such as depression, anxiety and obsessive compulsive disorder (8).

Treatment will look different for everyone and it might take some trial and error to find what works for you. If you recognise any of these red flags in your own thoughts and behaviours, or know you struggle with bulimia nervosa, please reach out to us for specialist support and complete an enquiry form where our team of specialist dietitians can support you.

Emily Green

TCN Intern

Emily Green

Emily is studying MSc Clincal 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] BEAT, n.d. Statistics for Journalists - Beat. [online] Beat. Available at: <> [Accessed 7 May 2022].

[2] DSM-V, 2013. Feeding and Eating Disorders. [online] DSM Library. Available at: <> [Accessed 4 April 2022].

[3] Priory, 2022. Eating Disorder Statistics. [online] Priory. Available at: <> [Accessed 5 April 2022].

[4] Keel, P., Bodell, L., Forney, K., Appelbaum, J. and Williams, D., 2019. Examining weight suppression as a transdiagnostic factor influencing illness trajectory in bulimic eating disorders. Physiology & Behavior, [online] 208, p.112565. Available at: <> [Accessed 18 May 2022].

[5] Hay, P. and Mitchison, D., 2014. The epidemiology of eating disorders: genetic, environmental, and societal factors. Clinical Epidemiology, [online] 6, p.89. Available at: <> [Accessed 16 May 2022].

[6] Thornton, L., Mazzeo, S. and Bulik, C., 2010. The Heritability of Eating Disorders: Methods and Current Findings. Behavioral Neurobiology of Eating Disorders, 6, pp.141-156.

[7] Fairburn, C. G., Marcus, M. D., & Wilson, G. T. 1993. Cognitive-behavioral therapy for binge eating and bulimia nervosa: a comprehensive treatment manual. In C. G. Fairburn, & G. T. Wilson (Eds.), Binge eating: nature, assessment and treatment (pp. 361–404). New York: Guilford Press

[8] NHS, 2022. Treatment - Bulimia. [online] Available at: <> [Accessed 6 May 2022].


Talia Cecchele Nutrition is a team of registered dietitians that specialise in eating disorders and disordered eating. 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.

London Dietitian. London Eating Disorder Dietitian. Eating Disorder Dietitian


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