Anorexia Nervosa Is Defined By Which Of The Following? | Core

Clinicians define this eating disorder by restrictive intake, intense fear of weight gain, and a distorted view of body size and shape.

Anorexia nervosa is an eating disorder where worries about weight, food, and shape start to rule daily life. Health professionals define it through a cluster of features, not one single sign, and those features affect thoughts, feelings, behaviour, and the body.

This article sets out those features in clear language, links them to standard criteria, and shows how they appear in day to day life. It is written for readers who want a grounded sense of what the diagnosis means, whether for themselves, a friend, or a family member.

Anorexia Nervosa Is Defined By Which Of The Following? Core Criteria Explained

Modern manuals such as the DSM-5 describe three main building blocks that define anorexia nervosa. All three sit together to form the diagnosis and must be evaluated by a trained health professional, not through a checklist at home. At the centre is low body weight caused by self imposed restriction, alongside intense fear of weight gain and a distorted view of the body.

Core Diagnostic Features Of Anorexia Nervosa

When a clinician thinks about this diagnosis, three linked features tend to stand out. Each one can look a little different from person to person, but the themes stay steady.

Restriction Of Energy Intake And Low Body Weight

The first feature is restriction of energy intake. The person takes in fewer calories than their body needs for age, height, sex, and physical health. Over time that mismatch leads to low body weight or a clear failure to grow as expected in children and teenagers. Restriction may involve tiny portions, skipped meals, avoidance of whole food groups, or a narrow list of “safe” foods, sometimes combined with heavy exercise, laxative misuse, or self induced vomiting.

Intense Fear Of Gaining Weight Or Becoming Fat

The second feature centres on fear. People with anorexia nervosa have a strong fear of gaining weight or “getting fat”, even when they are already underweight. That fear often does not fade as weight drops; in many cases it grows stronger, and the person doubles down on restrictive habits, avoids eating with others, dreads medical checks, or feels deep guilt after meals.

Disturbance In Body Image And Weight Perception

The third feature relates to how the person experiences their own body. A person with anorexia nervosa often misjudges their size, believing they are larger than they are. They may fixate on tiny folds of skin, feel “huge” even when there is clear evidence of low weight, or avoid mirrors and photos. Self worth can become tied to the number on the scale, the fit of clothes, or passing comments about appearance, and some people deny how low their weight has become or how ill they are.

How Manuals Such As DSM-5 Define This Eating Disorder

Diagnostic systems such as the DSM-5 give formal wording for these features. In that manual, anorexia nervosa involves restriction of energy intake leading to a low body weight for age, sex, developmental stage, and physical health, an intense fear of gaining weight or becoming fat, and disturbance in the way body weight or shape is experienced, or a persistent lack of recognition of the seriousness of the current low body weight.

National health services draw on that description when they explain this condition to the public. The NHS overview of anorexia nervosa describes people who keep their weight as low as possible through strict eating rules, exercise, vomiting, or laxatives, often while holding a distorted view of their bodies.

Large medical centres echo the same core elements. The Mayo Clinic description of anorexia nervosa notes low body weight, intense fear of weight gain, and a flawed way of seeing the body. The National Institute of Mental Health lists anorexia nervosa among serious eating disorders that disturb eating patterns, weight, and shape in daily life.

Taken together, these descriptions show a shared pattern across manuals and clinics. Low weight is not viewed in isolation; it sits alongside restrictive habits, intense fear of weight gain, and a troubled relationship with body image. This shared pattern shapes how professionals recognise anorexia nervosa in everyday practice.

Core Elements Summarised At A Glance

The table below gathers the main features in one place. It is not a tool for self diagnosis, but it can help people see how the pieces fit together.

Feature	Formal Description	How It May Show Up Day To Day
Restriction Of Intake	Ongoing restriction of energy intake leading to low body weight.	Skipping meals, tiny portions, strict food rules.
Low Body Weight	Weight that is below what is expected for age and height.	Noticeable weight loss, loose clothes, stalled growth.
Intense Fear Of Weight Gain	Strong fear of gaining weight or becoming fat.	Panic around weigh ins, worry after eating.
Distorted Body Image	Disturbance in how body weight or shape is experienced.	Feeling “huge” while underweight, frequent mirror checking.
Self Worth Tied To Weight	Self evaluation rests mainly on body shape or weight.	Mood rising or falling with the scale.
Lack Of Recognition Of Illness	Little sense of how serious the low weight is.	Insisting “I am fine” even with clear medical concern.
Compensatory Behaviours	Behaviours used to control weight, such as vomiting or laxatives.	Rigid workouts, secret bathroom trips after meals.

Subtypes And Related Patterns

Within anorexia nervosa, many manuals describe two subtypes. In the restricting type, weight loss stems mainly from dieting, fasting, and exercise. In the binge eating or purging type, the person also has episodes of binge eating or regular vomiting, laxative use, or enemas.

These subtypes do not change the core definition; they describe common patterns on top of the main criteria. Other eating disorders, such as bulimia nervosa and binge eating disorder, have their own criteria built around binge episodes, compensation, and body image. The National Eating Disorders Association summary of anorexia nervosa sets out these differences for the public.

Who Can Receive A Diagnosis Of Anorexia Nervosa?

While anorexia nervosa is often linked with teenage girls, it can affect people of any age, sex, or background. Children, teenagers, and adults can all meet the criteria when the features described above are present and intense enough to disturb health and daily life. Young people may not realise that their eating and exercise habits are putting their health in danger, and parents or carers might notice behaviour changes, dropped weight, missed periods, poor growth, fainting, or school problems before the young person sees a problem.

In adults, anorexia nervosa may start or relapse during periods of stress or illness. Partners, friends, or colleagues might be the first to notice secrecy around meals, tiredness, or strong worry about shape and weight. Anyone at any size can have an eating disorder, so professionals are urged not to rely on weight alone when deciding who needs care.

How Anorexia Nervosa Is Assessed In Practice

Only qualified health professionals can diagnose anorexia nervosa. They use tools such as DSM-5 criteria, medical examinations, blood tests, and conversations with the person and, when helpful, their family or carers. Guidance from bodies such as the National Institute for Health and Care Excellence explains that assessment should review physical risk, current eating patterns, beliefs about food and body, and any self harm or thoughts about ending life.

Assessment usually includes:

• A medical history, including weight changes and physical symptoms such as fainting or chest pain.
• A physical examination with blood pressure, pulse, temperature, and blood tests.
• Questions about thoughts and feelings around eating, weight, shape, mood, and safety.

The goal of this process is not to blame the person but to understand risk level and plan care. Early detection and treatment can lower the chance of long lasting medical complications. National data underline that anorexia nervosa has among the highest death rates of any mental health condition, which makes timely care urgent.

Warning Signs That May Prompt A Professional Review

The presence of one sign does not mean someone has anorexia nervosa. Still, certain patterns often prompt families or doctors to ask for a specialist opinion. The table below lists some of these red flags.

Area	Examples Of Concerning Signs	What They May Suggest
Thoughts And Feelings	Constant thoughts about food, calories, or exercise; strong fear of gaining weight.	Body size and intake may dominate day to day life.
Eating Behaviour	Skipping meals, hiding food, cutting food into tiny pieces.	Restriction of intake and secrecy around eating.
Movement And Exercise	Compulsive workouts, distress when unable to exercise.	Use of movement to “burn off” calories or ease distress.
Physical Changes	Noticeable weight loss, feeling cold, fine body hair, dizziness.	The body may be struggling to cope with low energy intake.
Social Life	Pulling away from friends, avoiding events with food.	Eating rules and weight worries may be pushing other parts of life aside.
School Or Work	Falling grades, loss of concentration, fatigue.	Eating disorder thoughts and habits may crowd out study or work.
Mood And Safety	Low mood, tearfulness, self harm, or talk about not wanting to be alive.	Risk of serious harm that needs urgent medical and mental health care.

Why Clear Definitions Matter

Shared definitions help families, teachers, and health teams pull in the same direction. When everyone understands that anorexia nervosa is defined by restriction, low weight, fear of weight gain, and distorted body image, it becomes harder to dismiss warning signs as “just a phase” or “dieting gone too far.” Agreed wording also guides research, service planning, and public health work on eating disorders.

Getting Help If You Are Worried

If you recognise several of the features described here in yourself or someone close to you, talking with a trusted health professional is the next step. That might mean a family doctor, school nurse, campus health service, or specialist clinic, depending on what is available where you live.

Emergency care is needed right away if someone with an eating problem has chest pain, serious shortness of breath, fainting, signs of dehydration, or thoughts of ending life. In those situations, local emergency services or urgent care lines can advise on the safest next step.

No article can replace a full assessment by a trained clinician. Still, understanding how anorexia nervosa is defined can make it easier to spot risk early, speak up, and ask for help. With skilled care, many people move toward recovery and rebuild a life where food and weight no longer take centre stage.