How are eating disorders classified medically?
Psychiatrists use two main systems: ICD-11, issued by the World Health Organization, and DSM-5, issued by the American Psychiatric Association (and its revision, DSM-5-TR). They group feeding and eating disorders in a single chapter, and agree on the main types although some details differ.
| Code | Disorder | Key feature |
|---|---|---|
| 6B80 | Anorexia nervosa | Severe restriction of eating with a fear of gaining weight or preoccupation with body shape |
| 6B81 | Nervous bulimia | Repeated binge episodes followed by compensatory behavior, with preoccupation with weight and shape |
| 6B82 | Binge eating disorder | Repeated binge episodes with loss of control and intense distress, without regular compensatory behavior |
| 6B83 | Avoidant/restrictive food intake disorder | Avoiding or restricting eating for reasons unrelated to weight or body image |
| 6B84 | Pica | Persistently eating non-food substances |
| 6B85 | Rumination-regurgitation disorder | Repeated, deliberate return of food from the stomach to the mouth |
| 6B8Y | Other specified feeding or eating disorders | Clinically significant presentations that do not meet the criteria of a particular type |
ICD-11 distinguishes between eating disorders, which usually involve preoccupation with weight and body shape, and feeding disorders such as pica, rumination and avoidant/restrictive food intake disorder, in which weight or shape is not the focus. On this page we concentrate on the five most common and important types.
What is anorexia nervosa?
Anorexia nervosa is a disorder in which a person restricts their food severely, so their weight falls below what is expected for their age, height and health, with an intense fear of gaining weight or behaviors that prevent it, and a disturbance in how they see their body or judge the seriousness of their condition. The name is somewhat misleading; the patient does not necessarily lose the sense of hunger, but resists it.
DSM-5 distinguishes two patterns: the restricting type, which relies on eating less, fasting or excessive exercise, and the binge-eating/purging type, in which binge episodes or compensatory behaviors occur. The doctor determines severity through a comprehensive medical assessment, not by a single number.
It is the least common type but carries the highest medical risk. It usually begins in adolescence or early adulthood and affects females more than males.
What is bulimia nervosa?
Bulimia nervosa is marked by repeated binge episodes during which the person feels a loss of control, followed by repeated compensatory behavior aimed at preventing weight gain, such as deliberate vomiting, misuse of laxatives, fasting or excessive exercise, with a self-evaluation that depends heavily on weight and body shape.
People with bulimia are often at a usual weight or above it, so the illness can go for years without anyone noticing. A notable feature of ICD-11 is that it relies on the sense of loss of control during the episode, not on the amount of food alone. The most dangerous aspects of this type are electrolyte imbalance and its effect on the heart, and its link with depression and substance use.
What is binge eating disorder?
Binge eating disorder is the most common among adults in American surveys. It is marked by repeated episodes of eating with a clear sense of loss of control, often accompanied by eating quickly, eating until uncomfortably full, or eating alone out of shame, followed by intense distress and guilt, without regular compensatory behavior as in bulimia.
It is a medical diagnosis recognized in ICD-11 and DSM-5, not “gluttony” or weak willpower. It differs from passing overeating on occasions, and from daily emotional eating driven by stress or boredom; the latter is a common behavior we cover on the food addiction and emotional eating page, whereas binge eating disorder is a condition that causes great suffering and needs specialist treatment.
What is avoidant/restrictive food intake disorder (ARFID)?
ARFID was added as a diagnosis in DSM-5 and then in ICD-11. It is marked by avoiding or restricting food to a degree that leads to a nutritional, weight or growth deficiency, dependence on nutritional supplements, or clear disruption of social life, without the motive being a fear of gaining weight or body image.
Refusing many foods because of taste, texture, smell or color.
Poor appetite, little interest in eating, and getting full quickly.
Fear of choking, vomiting or pain after a frightening experience.
It often begins in childhood and may continue into adulthood. It is more common in males than the other types, and is linked with autism, ADHD and anxiety disorders. It differs from a “difficult eater” in that it clearly affects growth, health or daily life.
What are other specified feeding or eating disorders (OSFED)?
This category is used when a person has a real eating disorder that causes clear distress or disruption, but whose presentation does not exactly meet the criteria of a particular type. The NHS notes that it is the most commonly diagnosed eating disorder, and it is wrong to consider it “milder” than the others; it can be just as serious.
- Atypical anorexia: All the features of anorexia nervosa are present, but weight is still in the usual range or above despite major loss. It can carry the same medical risks.
- Bulimia or binge eating of lower frequency or shorter duration: The same picture, but not reaching the frequency or duration required for the full diagnosis.
- Purging disorder: Repeated compensatory behaviors without binge episodes.
- Night eating syndrome: Repeated episodes of eating at night or after waking from sleep, with awareness of them and distress about them.
NICE guidelines recommend treating these conditions with the methods of the closest type. If there is not enough information to determine the picture, a diagnosis of “unspecified eating disorder” may be used temporarily.
What is the difference between the main types of eating disorders?
| Point of comparison | Anorexia nervosa | Nervous bulimia | Binge eating disorder | ARFID |
|---|---|---|---|---|
| Core area | Restriction and fear of gaining weight | Binges followed by compensatory behavior | Binges with loss of control | Avoidance due to sensory reasons, fear or low interest |
| Preoccupation with weight and shape | Often severe | Severe | Present in many | Usually absent |
| Typical weight | Lower than expected | Usually normal or higher | Usually normal or higher | May be low or normal |
| Common age of onset | Adolescence and early adulthood | Adolescence and early adulthood | Onset of puberty and after | Often childhood |
| Main medical risk | Heart complications and malnutrition | Electrolyte imbalance and the heart | Metabolic complications and depression | Undernutrition and delayed growth |
What are pica and rumination disorder?
Pica is the persistent eating of non-food substances inappropriate to the person's age or culture, such as clay, ice or paper. It may sometimes be linked to iron deficiency or developmental disabilities, and needs a medical assessment to rule out complications. Rumination disorder is the repeated return of food from the stomach to the mouth after eating, and needs to be distinguished from digestive diseases.
Can one type of eating disorder turn into another?
Yes, and this is common. A disorder may begin as restriction and then binges appear, or bulimia may change into binge eating without compensatory behavior, or the reverse. So a diagnosis is not a permanent “stamp” but a description of the current picture, which the doctor reassesses over time and adjusts the treatment plan accordingly.
Are “orthorexia” or “bigorexia” official types?
Orthorexia is a common term for an unhealthy preoccupation with “healthy” or “clean” eating that reaches dangerous restriction, and bigorexia is a term for a compulsive preoccupation with being too small in muscle among some men. Neither is a separate diagnosis in ICD-11 or DSM-5, but the suffering is real, and a doctor may diagnose them under other specified feeding or eating disorders, or under body dysmorphic disorder, or otherwise depending on the picture.
What matters is that a label does not stop you from asking for help. If food or the body controls your life and causes you distress, that deserves an assessment whatever the name. Learn about the signs of eating disorders to know when to ask for help.