Throughout this website and others you may visit on the Internet, terms like "eating disorders" and "disordered eating" are used. These terms can sometimes be confusing, so we have developed the following glossary of definitions to clarify their meaning and use, as well as definitions for other frequently used terms.


Anorexia Athletica (Compulsive Exercising)

Anorexia athletica is a condition where people over-exercise because they believe this will control their bodies and give them a sense of power, control and self-respect. It isn't a clinically recognized diagnosis in the same way that anorexia nervosa and bulimia nervosa are, but compulsive exercising can have serious health consequences.

Symptoms of anorexia athletica include:

  • Exercising more than is good for our health.
  • Being fanatical about our weight and diet.
  • Taking time off work, school and relationships to exercise.
  • Focusing on the challenge exercise poses and forgetting that it can be fun.
  • Believing that our self-worth depends on our physical performance.
  • Rarely being satisfied by what we achieve physically.
  • Saying that this exercise is okay because we are athletes, or insisting that the behaviour is healthy.

More Information:

Virtual Pediatric Hospital
Peak Performance Online

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Anorexia Nervosa

People who have anorexia nervosa are obsessed with controlling their eating. The reason for their obsession is the belief that by controlling their bodies they can control their lives. This obsession is usually achieved through starvation.

Anorexia nervosa most commonly begins during puberty and can be recognized by the following symptoms:

  • Losing a lot of weight.
  • An inability to maintain a weight that is normal for our age and height.
  • An obsessive desire to be thinner.
  • Being very afraid of gaining weight or becoming "fat".
  • Being unable to see our body as it really is: it always seems larger than it actually is.
  • Allowing our weight and shape to overly influence how we feel about ourselves.
  • A powerful desire to take control of our lives and feel competent. We believe we can achieve this by controlling our eating and weight.

Anorexia and bulimia have similar symptoms. However, anorexia can be recognized by the following:

  • Significant weight loss without any logical reason, like illness.
  • Significant reduction in eating accompanied by repeated denials of hunger.
  • Dieting when not over our healthy weight range.
  • Signs of starvation. This can include the thinning or actual loss of hair, the appearance of a fine, white hair on the body, frequent bloated feelings, yellowing palms or soles of feet and/or a dry, pasty skin.
  • Abnormal menstrual periods in women.

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Binge Eating Disorder (BED)

Individuals with binge eating disorder eat excessive amounts of food at one time. They do this for two reasons:

They are very hungry because they have been dieting or restricting their eating in some way. The binge is a response to that hunger.

They over-eat to comfort themselves, to avoid uncomfortable situations, or to numb their feelings. The binge is an attempt to soothe themselves emotionally.

People who binge-eat are often ashamed and embarrassed. They also tend to be genetically heavier and larger than the "average" person. They do not, however, generally try to compensate for their over-eating by vomiting, fasting, over-exercising or abusing laxatives as people with anorexia or bulimia may do.

Symptoms of binge eating disorder include:

  • Eating large amounts of food frequently and in one sitting.
  • Feeling out of control and unable to stop eating.
  • Eating quickly and in secret.
  • Feeling uncomfortably full after eating.
  • Feeling guilty and ashamed of their binges.

In addition, people who binge eat may have a history of diet failures, and may also be obese. About one in five obese people engage in binge eating.

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Body Mass Index (BMI)

The Body Mass Index is a method for calculating our 'normal' or 'healthy' body weight. It does so by measuring the amount of fat on your body in relation to the amount of muscle. You can do this by weighing yourself (in kilograms) and dividing this by the square of your height (in metres). The formula is weight in kilograms/height in meters2.

BMI should never be used as the only measure of your health or weight. It has a number of limitations. It was developed for use on adults over the age of 18 and is therefore not of much use when assessing young adults who have not reached full growth. It is also not that useful when assessing:

  • Individuals who are very muscular.
  • Individuals who are naturally lean.
  • Adults over 65 years of age.
  • Pregnant and lactating women.

More Information:

Public Health Agency of Canada
Health Canada
World Health Organization

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Bulimia Nervosa

Bulimia nervosa is characterized by cycles of bingeing and purging. As with anorexia, this behaviour is driven by a desire to regulate feelings, and with worries about body weight and shape.

The cycle begins with the person rapidly eating large amounts of food in a single sitting. The eating feels automatic and helpless. This may, initially, numb uncomfortable feelings, like anger or sadness. But it also creates physical discomfort and anxiety about weight gain. As a consequence, the person tries to rid the body of the food that was consumed. This is attempted by vomiting, using laxatives, enemas or diuretics, by exercising excessively, by skipping meals or by dieting.

These purging behaviours don't achieve the desired goals - to feel more physically comfortable and not gain weight. Instead, they are very harmful to health.

Symptoms of bulimia nervosa include:

  • Repeated episodes of bingeing and purging.
  • Feeling out of control while eating.
  • Vomiting, using laxatives, diet pills or diuretics, exercising excessively, and skipping meals to rid the body of food.
  • Frequent dieting.
  • Using body weight and shape as the main measure of one's self-worth.

People with bulimia may well have a weight that is regarded as "normal".

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Clinical Eating Disorders

Clinical eating disorders are eating disorders that are recognized as medical conditions. These include:

  • Anorexia nervosa
  • Binge eating disorder
  • Bulimia nervosa
  • Eating disorder not otherwise specified (ED-NOS)

There are strict criteria to define these conditions. These clear definitions help health workers understand how each condition develops and progresses, and how to treat people with similar symptoms.

Although some people may not fit the exact criteria for a clinical eating disorder, they can still seek help. This is discussed under Disordered Eating.

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Dieting is about restricting what we eat or how much we eat in order to lose weight. We usually diet because we believe that being thinner will make us healthier, happier and more worthy.

The pressures to diet in contemporary society are huge. They are driven by a media and diet industry that defines 'normal' weight and shape as unhealthily thin. This makes it difficult for us to understand that healthy and happy people come in all shapes and sizes. It also encourages the false belief that everyone can be slim if they try hard enough.

Dieting can lead to eating disorders because it encourages an obsession with food and weight, and suggests that thinness is an ideal to which we must strive. The effects of dieting include:

  • A preoccupation with food.
  • A strong desire to binge.
  • Mood changes, like increased irritability and depression.
  • Increased nail biting or other self-soothing behaviours.
  • Lowered self-esteem when diets inevitably fail.
  • Social withdrawal.
  • Reduction in sexual interest.
  • Impaired concentration and judgment.
  • Decreased body temperature, heart rate and respiration.
  • Lowered metabolism and thus weight gain.
  • Increased use of salt, spices, coffee, tea, chewing gum, cigarettes.

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Disordered Eating

Disordered eating includes a wide range of abnormal eating. This includes the behaviours seen in eating disorders such as anorexia and bulimia, chronic restrained eating, compulsive eating and habitual dieting. It includes irregular, chaotic eating patterns. Often physical hunger and satiety (fullness) are ignored.

Disordered eating has negative effects on overall health - emotional, social and physical. It may cause the individual to feel tired and depressed, decrease mental functioning and concentration, and can lead to malnutrition with risk to bone health, physical growth and brain development.

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Eating Disorder Not Otherwise Specified (ED-NOS)

Individuals who experience a mix of anorexia and/or bulimia and/or binge-eating symptoms, but who don't fall neatly into one of the medical categories, are said to have an eating disorder not otherwise specified (ED-NOS). These individuals should also receive the help and resources provided to individuals who have a "neat" clinical diagnosis.

For instance, individuals with ED-NOS may exhibit all the symptoms of anorexia but:

  • Women may continue to experience menstruation.
  • Men won't typically experience abnormally low sex hormones.
  • Both men and women may lose weight but still remain in the normal weight range.

Others may have all the symptoms of bulimia, but won't binge and/or purge as often as is required to be categorized as having bulimia.

Many people with ED-NOS also engage in other symptoms associated with anorexia, bulimia or binge eating, like:

  • Purging, or compensating for normal eating by inducing vomiting, using laxatives or over-exercising - but don't do it often enough to be diagnosed with one of the other clinical eating disorders.
  • Chewing food repeatedly and often spitting it out rather than swallowing it.
  • Binge eating regularly and compensating for it through the use of laxatives or by vomiting, etc.
  • Remaining within their normal weight range despite disordered eating.

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Metabolism describes the chemical processes that occur within a living cell or organism, and which are necessary for the maintenance of life. In metabolism some substances are broken down to yield energy for vital processes while other substances, necessary for life, are synthesized.

Resting metabolic rate (sometimes called basal metabolic rate) represents the calories that we use when at rest and simply breathing. This energy is used for cell growth and repair, and other bodily functions.

Diet-Induced Thermogenesis is metabolic functioning related to digestion of food, and the active uptake of nutrients into the blood.

Adaptive Thermogenesis is the energy that the body uses in maintaining a normal temperature.

We have almost no control over these processes.

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Night-Eating Syndrome

Individuals with night-eating syndrome tend to limit their eating during the day, and then eat at night to compensate. Predictably, this pattern of self-starvation commonly causes sleep disturbances. Biological and emotional factors - hormones related to stress, sleep and hunger - contribute to this kind of behaviour. Although rare, a slightly higher percentage of obese individuals and those with bulimia experience it.

Symptoms include:

  • Little or no appetite for breakfast.
  • Eating more than half of one's daily food intake after dinner. This behaviour continues over a period of at least three months.
  • Feeling tense, anxious, upset or guilty while eating.
  • Having difficulty falling asleep or staying asleep.
  • Eating continually in the evening rather than bingeing in relatively short episodes.
  • Experiencing guilt and shame from eating rather than enjoyment.

Night-eating syndrome has not been formally defined as an eating disorder.

More Information:

University of Pennsylvania Health System
Overcoming the night eating syndrome: a step-by-step guide to breaking the cycle. Written by Allison KC, Stunkard AJ, Their SL. (2004). Oakland, CA: New Harbinger

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Nocturnal Sleep-Related Eating Disorder

People with nocturnal sleep-related eating disorder may binge, or consume strange combinations of food, raw foods and even non-food items in the period between wakefulness and sleep. Upon waking up, the person has little or no memory of doing this.

Although nocturnal sleep-related eating disorder is found across ages and in both males and females, more females appear to be affected. It is thought to be a sleep disorder rather than an eating disorder.

More information:

National Sleep Foundation

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Obesity means too much fat tissue compared to lean tissue in the body. However, the term is often used loosely to describe the fact that many people are fatter than society's thin ideal.

The World Health Organization defines someone as obese if their Body Mass Index (BMI) is higher than 30. See Body Mass Index for information on the limitations of the BMI.

Obesity is not just a consequence of over-eating and under-exercising, as popular media often suggest - it is a condition affected by a person's genes, environment, emotions and behaviour.

Obesity may affect one regardless of sex, age, geography or socio-economic group. However, poor people are often at greatest risk.

Obesity is not an eating disorder, although some obese individuals may also have eating disorders.

More Information:

World Health Organization
Public Health Agency of Canada
Academy of Nutrition and Dietetics
National Association to Advance Fat Acceptance

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Orthorexia ("Correct" Eating Disorder)

Orthorexia is a cluster of food- and weight-related symptoms, including:

  • Eating only foods regarded as healthy.
  • Relying only on "natural" products to treat an illness.
  • Finding more pleasure in eating "correctly" rather than in simply eating.

Although orthorexia is not a recognized diagnosis, it does - like other forms of disordered eating - lead to an obsessive focus on food. People with orthorexia experience emotional satisfaction when they stick to their goals, but intense despair when they fail to do so. Weight is commonly used as a measure of their success. Their behaviours and beliefs can lead to social isolation and ill health.

More Information:

National Eating Disorders Association
Palo Alto Medical Foundation

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Being "overweight" generally refers to weighing more than some defined standard. Originally, this standard was established by life insurance companies.

However, the term is used very loosely. People who are simply larger than the cultural ideal, or who are over their preferred weight, are often described as "overweight". In Western societies this cultural ideal, and thus our preference, is unhealthily thin.

The World Health Organization defines "overweight" as having a Body Mass Index of between 25 and 29. See Body Mass Index for information on the limitations of the BMI.

More Information:

World Health Organization
Health Canada
Academy of Nutrition and Dietetics
National Association to Advance Fat Acceptance

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Pica is an eating disorder characterized by the eating of things that are not food. Children between 18 months and two years of age often eat dirt or other things, but this is typically a normal part of their development. If this behaviour reoccurs later in life, however, it is regarded as an eating disorder. People with pica crave things like dirt, clay, chalk, paint chips, laundry powders, cigarette ashes, rust or plastic.

Pica occurs most commonly in people who:

  • Are pregnant.
  • Have poor eating habits.
  • Have developmental disabilities.
  • Have psychiatric difficulties.

Pica can be harmless unless the substances consumed are toxic or contaminated. In these cases individuals can get very sick or die.

More Information:


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Prader-Willi Syndrome

Prader-Willi Syndrome is a rare genetic disorder characterised by:

  • Cognitive problems.
  • Decreased muscle tone.
  • Short stature.
  • Mood swings.
  • Chronic hunger, which can lead to excessive eating and life-threatening obesity.

The condition varies quite widely among affected individuals. Both sexes are affected.

More Information:

Foundation for Prader-Willi Research
Prader-Willi Association USA
National Institutes of Health

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Rumination means spitting up and chewing food over and over again. People who do this spit up effortlessly, without gagging or retching. They spit up soon after they eat, and can chew their food for hours. Most infants spit up and chew their food in this way, however, they soon outgrow this behaviour. When children do not outgrow it, parents should ask for help.

More Information:

National Institutes of Health
University of Rochester Medical Center

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