Eating Disorders
(Bulimia · Anorexia · Binge eating)
In this condition factsheet:
The Facts on Eating Disorders
More people are being diagnosed with eating disorders, possibly as a consequence of society's emphasis on and preoccupation with thinness. Eating disorders are conditions that involve genetic, biological, psychosocial, and environmental factors. Common types include anorexia nervosa, avoidant and restrictive food intake disorder, bulimia nervosa, and binge eating disorder. More women than men are affected by eating disorders.
Anorexia nervosa is a psychiatric condition in which people restrict their food intake or use behaviours to prevent weight gain, because of a false belief that they are fat or for fear of becoming fat or obese. In reality, people affected by this condition are almost always underweight or of normal weight when the condition starts. It is estimated that more than 90% of all those diagnosed with anorexia nervosa are women, often from middle and upper socioeconomic backgrounds. This disorder usually starts in the years between adolescence and young adulthood, with the average age of onset at 18 years. It is rare for anorexia to start after the age of 40. It is estimated that in their lifetimes, 9 in 1,000 females and 3 in 1,000 males will be diagnosed with anorexia.
Avoidant and restrictive food intake disorder commonly starts during infancy or childhood. This involves a fear of eating certain foods due to characteristics such as their colour, odour, or texture. Foods may also be avoided if they have caused trauma in the past, such as choking or vomiting. Unlike "picky eating", people living with avoidant and restrictive food intake disorder can experience nutritional deficiency and weight loss, affecting their growth and development.
Bulimia nervosa is an eating disorder characterized by repeated and uncontrolled or compulsive binge eating, usually followed by inappropriate ways of trying to get rid of the food eaten. Most often, this involves purging by self-induced vomiting or abuse of laxatives, enemas, or diuretics. It's also sometimes called the "binge-purge syndrome." Some people with bulimia don't purge, but will binge-eat (consuming as many as 20,000 calories at one time) and then compensate for binge eating sessions with other behaviours such as fasting or over-exercising. A person with bulimia may secretly binge anywhere from once a week to several times a day. In most cases, binge eating is followed by purging. A person with bulimia may use as many as 20 or more laxatives at a time.
Bulimia commonly appears in the latter part of adolescence or early adulthood, but it can develop at an earlier or later age. The estimated lifetime incidence of bulimia nervosa is about 1%, with females being 3 times more commonly affected than males.
Binge eating disorder is characterized by the same uncontrollable binge eating that is seen in bulimia nervosa, but without any purging behaviours after binge eating episodes. This condition is distinct from overeating or obesity. The estimated lifetime incidence of binge eating disorder is approximately 2%. It is more common in women than men, and the age at diagnosis tends to be older than anorexia and bulimia.
Causes of Eating Disorders
Eating disorders are generally viewed as being psychological in origin. However, like depression, schizophrenia, and bipolar affective disorder, they are currently believed to have many causes, including genetic and functional changes in the brain. People suffering from anorexia and bulimia have preoccupations with body image, weight, and eating. They also have a distorted personal body image and a fear of fatness and weight gain. People living with eating disorders are often affected by other psychiatric problems.
Although cultural factors have an influence on the development of eating disorders, they appear to stem from multiple factors. There has been a lot of debate about the role of parenting and family environments in relation to eating disorders. Genetic and hormonal factors are believed to play significant roles; people with eating disorders are believed to have a genetic predisposition to the illness. There also appears to be a neurological relationship between patterns of eating (such as dieting and starvation) and the nervous and hormonal systems, since hunger, food cravings, and feelings of fullness are controlled by certain areas of the brain and involve a number of digestive hormones.
Symptoms and Complications of Eating Disorders
People with anorexia nervosa may appear severely emaciated due to malnutrition; sometimes their ribs can be seen through the skin. Other common symptoms of anorexia include:
- constipation
- decreased libido
- dehydration
- depression
- dizziness
- dry, scaly skin
- hair loss
- faintness or weakness
- inability to concentrate
- intolerance to cold
- irritability
- loss of body fat
- low blood pressure
- missed, or absence of, menstrual periods
- psychological fears of obesity and weight gain
- slow or irregular heartbeat
While most people feel hungry and uncomfortable when their calorie intake is low or restricted, people with anorexia suppress this discomfort and usually lose the ability to appreciate normal hunger cues. As they begin to starve, they may experience a feeling of euphoria, similar to how a runner or jogger gets the well-known "runner's high."
If the onset of anorexia occurs before puberty, a girl's sexual development will stop and menstruation won't begin. Severe anorexia leads to chronic malnutrition, which has damaging effects on the body, especially the bones, thyroid, heart, and digestive and reproductive systems. Anorexia can be fatal. A quarter of those who die with anorexia die of suicide.
A person with anorexia will generally have an obsession with food, and may display behaviours such as excessive calorie counting, saving recipes, and concealing or wasting food. They will often claim to eat much more than they actually do.
People with avoidant and restrictive food intake disorder can experience similar signs of weight loss and malnutrition as seen in anorexia nervosa. As this disorder is marked by an avoidance or refusal of specific types of foods, affected individuals may also avoid normal social activities that involve eating. In certain cases, people living with this disorder can become dependent on nutritional supplements to make up for reduced food intake. If left untreated, children with avoidant and restrictive food intake disorder may develop into anorexia or bulimia later in life.
Some people with bulimia may experience episodic weight loss, while others maintain a normal weight or may even be overweight. In some cases, menstrual cycles may be affected and stopped, but menstruation is usually preserved. Possible symptoms of bulimia include:
- dehydration (due to excessive use of laxatives or frequent self-induced vomiting)
- tooth decay and erosion (due to the acids that are brought up from repeated self-induced vomiting)
- low blood pressure
- constipation
- swollen saliva glands in the cheeks (like mumps)
- abnormal hormone levels
- stomach and esophagus problems
- irregular heartbeat
A variety of complications can result from the constant vomiting. For example, inflammation of the esophagus (called esophagitis) and severe dental problems can occur. At its worst, constant purging can lead to heart damage. People with bulimia may have a history of anorexia or obesity. They may also have psychiatric problems such as depression, panic disorder, social phobias, and anxiety disorders, as well as addictive behaviours like alcohol or drug abuse. A person with bulimia will likely feel more awareness of and remorse for their disorder than a person with anorexia. They are also much less likely to have nutritional deficiencies and lose weight.
People with binge eating disorder experience the same binge eating seen in those with bulimia nervosa, but do not have compensatory behaviours, such as induced vomiting, after binge eating.
Some symptoms of binge eating disorder include:
- eating more food within a period of time than most people in similar circumstances
- feeling a lack of control over eating during an episode
- eating until uncomfortably full or more rapidly than normal
- eating large amounts of food when not hungry
- eating alone or in secret because of embarrassment at how much one is eating
- feeling depressed, guilty, or disgusted with oneself after an episode
