Types of eating disorders – an outline

Types of eating disorders – an outline

Here’s an outline of some of the eating disorders around. Causes are complex, but all can be helped with diet. Do I work with people with an ED? Yes.

Feel Fab Nutrition - eating disorders can hit many people
Feel Fab Nutrition – eating disorders can hit many people

(However, if necessary, in conjunction with their doctors and therapists – talk with me on that one.)

Anorexia nervosa (AN)

Anorexia Nervosa (AN) usually begins during mid- to late-adolescence or in early adulthood, and is usually chronic rather than acute. The core features of AN include:

  • Pre-occupation with body weight (fear of fatness or pursuing thinness)
  • Severe food restriction
  • Maintenance of abnormally low body weight (at least 15 percent below that expected; in adults the BMI is below 17.5)
  • An intense fear of gaining weight (even though underweight… though not in their eyes)
  • An excessive influence of body weight and shape on self-evaluation
  • Failure to gain weight during the expected growth spurt of puberty (ie, becoming underweight without weight loss)

Weight loss in anorexia nervosa is enabled by avoiding ‘fattening foods’ (which can encompass just about any food). Some sufferers also exercise excessively and others purge (by vomiting or misuse of laxatives).

AN often starts with dieting behaviour and weight loss results that can draw compliments and not evoke concern. The problem comes, however, when the commitment to dieting increases: onlookers sometimes also start to notice rigidity, social withdrawal, obsessive behaviour and similar; this occurs more with people who were already withdrawn, obsessive, etc.

Sometimes a person, following a viral or chronic illness which resulted in weight loss, will develop AN through a pattern of purging behaviour; this is more likely if the weight loss became positively valued.

In AN, weight loss is experienced as a positive achievement and there is a polite or vocal bewilderment over others’ wishes to see the person put in weight. The positive achievement if controlling weight can be strongly reinforcing to someone with low confidence and poor self-esteem, so they have further reason to deny the need for weight gain.

That said, the essential role of ‘weight phobia’ is increasingly being questioned: some researchers and health professionals now believe it is culture-specific. Maybe it is a bit of both. AN is also often associated with psychiatric comorbidities severe medical complications and has a mortality rate as high as any psychiatric illness. In fact, this is the most fatal mental disorder, having an estimated mortality rate of around 10 percent[i].

Bulimia nervosa (BN)

BN is characterised by:

  • Recurrent episodes of binge eating, usually accompanied by a (subjective) feeling of loss of control over eating
  • Compensatory behaviour – self-induced vomiting, purging (with laxatives and/or diuretics), fasting or exercising or a combination of these – in order to prevent weight gain.

In addition, a sufferer may (mis)use thyroxine, amphetamine or other medications.

While the main age of AN onset 16-17, it is 18-19 for BN. Like with AN, self-evaluation and self-value of a bulimic is based around/influenced by body shape and weight; indeed, he or she may have had an earlier episode of AN.  If someone is presenting with a mix of AN and BN symptoms they will be diagnosed with AN if they have a BMI below 17.5, and BN if their BMI is over 17.5 (and the child/adolescent equivalent).

Like those with AN, people with BN tend to hide their behaviour and avoid seeking treatment, at least initially. Often they don’t seek treatment both because the condition can include guilt and shame (not least because of the pejorative language used about the actions of the condition) and because they are fearful they will be stopped from vomiting and purging – not a problem in itself, but the subsequent weight gain is (in their eyes).

Initially, those with bulimia nervosa are generally secretive about their bulimic episodes, though many eventually seek help. (Some may leave obvious signs around, such as empty food packaging or bags of vomit in a desire to be ‘found out’.)

Sometimes BN develops from a pre-existing anorexic illness; if it doesn’t, the development is still often similar, frequently arising from a background of attempts to restrain eating. However, with BN, the person cannot restrict food for so long and they ‘succumb’* to episodes of reactive binge eating, which result from a combination of physiological and psychological factors. (*They see it as weakness; it is instead an imperative physical manifestation of a biochemical reaction.)

After binging, the bulimic will engage in compensatory behaviours so as to keep their weight down. This becomes cyclical so the sufferer tries to diet à binges à purges à goes back on a diet à etc. This can all happen within a day.

As a result the bulimic can often look a normal weight despite overeating at times. However, BN behaviour dominates thoughts, meaning whole days may be re-organised around shopping, eating and purging. Indeed, bulimic episodes are frequently planned; for example, food is bought or prepared when the person knows they will be able to eat it without interruption.

In addition, the person will avoid situations such as eating out with others so they won’t be exposed to food they will want to eat and/or won’t be able to purge afterwards. Of course, this avoidance behaviour just adds to any relationship and social difficulties that may already be present.

Bulimics are often anxious and tense and experience mood disturbances. When they overeat or purge they can experience self-disgust and self-denigratory thoughts. Also, it is common for bulimics to have experienced previous physical or sexual abuse, so they will have already learned to think badly of themselves. Others may have a history of poor relationships and yet others of poor impulse control, alcohol and drug abuse. All these things are going to impact on their actions and how to help them.

Bulimic anorexia nervosa (BAN)

This is where AN and BN overlap and is also known as ‘anorexia, binge-purge subtype’. Essentially, anorectics do not usually purge and bulimics are usually a normal weight: in BAN, the sufferers are underweight, eat little and purge.

One study[ii] sought to compare female restricting anorectics, bulimic anorectics and normal-weight bulimics with reference to depression. They found:

  • All three groups were highly correlated with each other
  • Although depression was the peak scale for both anorectic groups, the bulimic anorectics were more depressed

They also found, through using the psychopathic deviate scale (PD[1]), that there is a similar set of personality features in AN, BAN and BN.

Exercise Bulimia (EB) or Obesssion with fitness (OF)

This is where excessive exercise is used as a form of purging. DR Theodore Weltzin, MD, Medical Director of Eating Disorder Services, Rogers Memorial Hospital (in the US) says, ‘Excessive exercising is an often overlooked component of eating disorders. For both males and females, participation in athletics and attempts at improving athletic performance can initiate an eating disorder.’

How does OF start? The causes are numerous. One quite common one is where it grows out of student athletes’ demanding practice schedules and their own drive to excel. Add external pressures (from coaches, peers, or parents) and he or she ends up believing that just one more workout will make the difference between first and second place… and then just keeps adding more workouts.


Someone with OF might:

  • Exhibit intense anxiety if they are unable to engage in their chosen exercise activity every day
  • Plan out their day prominently focusing on exercise; that is, they schedule other activities around their exercise goals
  • Reduce social, school and work activities in order to exercise
  • Show poor interpersonal, occupational and academic functioning
  • Exercise even if injured (including bone fractures)

For OFers, the act of exercising can increase anxiety and stress rather than, as is normal with exercise, decrease it. Excessive exercisers report that they often feel like they are not good enough, not fast enough or not pushing themselves hard enough during a period of exercise. They report feeling an intense pressure to increase the duration, intensity or difficulty of their exercise routine.

Eventually, OF can precipitate other compulsive behaviour, such as obsessive thoughts and keeping journals about perceived flaws and strict dieting. However, for people with an ED, the relationship between exercise and abnormalities may be more complex than simply purging calories and both psychological and biological causes contribute to excessive exercise in eating disorder patients. For example, in anorectics, excessive exercisers often have prominent anxiety symptoms (Penas-Lledo et al, 2002).

Studies show:

  • Restrictive eating increases activity in both humans and animals
  • This increase may relate to serotonin or leptin mediated effects on anxiety and appetite (Holtkamp et al, 2004)
  • In eating disorder patients, excessive exercise and perfection also predict dietary restraint (McLaren et al, 2001)
  • Excessive exercise, like self-induced purging, is a psychological reaction to uncomfortable internal states (like high levels of depression or anxiety)
  • ED patients who engage in excessive exercise are, in general, more likely to be depressed; they may exercise to attain relief (‘exercise highs’)

Of course, the whole situation is not helped as many OFers are led to believe calories in = calories out; that is, if they exercise more (and eat the same, or less), they will lose weight. Of course, under normal circumstances, exercise begets either eating, or compensating by moving more slowly later/sleeping more, or one’s BMI decreases; it is the type of calories eaten that matter, but they don’t see this. It takes tremendous (unhealthy) will to overcome the need to eat/rest.

Atypical eating disorders (eating disorders not otherwise specified; EDNOS)

(NOTE: This, strictly speaking, includes BED, but I’ll list it separately below.)  A number of people suffer from eating disorders that:

  • Are in many ways like AN and BN
  • But do not meet the precise diagnostic criteria for these conditions[2]
    • Eg, patient is just above the diagnostic threshold for AN
    • Eg, the (female) patient is still menstruating
    • Eg, binge eating and purging may occur less frequently than specified for a diagnosis of BN
  • However, over-concern with weight and shape and/or maintaining strict control over eating is generally present
  • And many of these non-typical eating disorders are as severe and long lasting as AN and BN

Thus, in Europe at least, these conditions are often termed ‘atypical eating disorders’; the North Americans call them ‘eating disorders not otherwise specified’[3].

Binge eating disorder (BED)

BED is a more recently described condition whereby individuals engage in uncontrollable episodes of binge eating… but do not use compensatory purging behaviours. To be BED, a person regularly does three or more of:

  • Eating more rapidly than normal for most people
  • Eating until feeling uncomfortably full
  • Eating large amounts of food when not physically hungry (they may be mentally hungry)
  • Eating alone (often because of embarrassment at the amount being eaten)
  • Eating so much they feel self-disgust, distress and guilt
  • Practising social avoidance

Defining binge eating can be problematic, not least because subjective self-reporting of binging does not always meet clinical criteria of binging. BED tends to develop in the 30s and 40s rather than teens and 20s, and is more often associated with obesity. From what I have seen, I think it is much to do with trying calories restricted diets whereby, in the end, the body’s biochemical and physical responses to what amounts to starvation mean the person will end up bingeing.

Food avoidance emotional disorder (FAED)

Food avoidance emotional disorder (FAED) is a childhood emotional disorder. Here, the prominent feature is food avoidance (in quantity and range) which results in weight loss. Notably FAED

  • Is primarily a mood, rather than food, disturbance
  • Starts early: children with FAED tend to be younger than those with early onset AN
  • Is more common in boys than girls

Selective eating and food fads (SEFF)

SEFF is a childhood condition whereby:

  • It often starts in toddlerhood
  • More boys than girls develop it
  • Means food intake is limited to a very narrow range of preferred foods; these foods are typically high in carbohydrates
  • Weight is generally not adversely affected
  • The child is not preoccupied with weight and shape
  • Growth may be affected
  • Social avoidance, anxiety and conflict can occur

SEFF is often temporary and so tend to resolve as the child grows into middle childhood (or, sometimes, adolescence).

Pervasive refusal syndrome (PRS) or Pervasive arousal withdrawal syndrome (PAWS)

Pervasive refusal syndrome (PRS), now referred to as Pervasive arousal withdrawal syndrome (PAWS), is a rare but serious child psychiatric disorder. It was first described by Bryan Lask et al in 1991.

PRS is:

  • Refusal by a child to or care for him or herself in any way over a period of months; that is, they refuse to eat, drink, walk or even talk
  • A life threatening condition requiring hospital admission

The disorder usually begins with a ‘virus’, or the child having a ‘pain’, even though no substantial cause can be found[4]. PRS starts slowly, but the child then worsens quickly, needing specialist medical care. Recovery is not guaranteed, but once healthy again, relapse is unusual.

Compulsive overeating (CO)

Similar in many ways to BED, CO is the perhaps the most common eating disorder. It:

  • Affects men nearly as often as women and usually starts in adulthood
  • Includes binge eating, rapid eating, eating large amounts even when not physically hungry
  • Brings about mood swings and eating alone (due to shame & embarrassment)
  • Involves preoccupation with food, weight, shape, appearance and guilt

People with CO usually have a history of multiple failed diet/weight loss attempts and, despite these persistent attempts at dieting, attempts, are generally typically above average weight.


Obesity, defined in adults as having a BMI of 30 or over[5], is less a food disorder than a hormone disorder. While obesity is statistically linked to a variety of health problems, there is growing controversy about whether a causal relationship exists. It is part of the metabolic syndrome and BMI says nothing about a how the fat is distributed and how much muscle there is, a person’s eating behaviours (clues, but not certainty), mental health, physical health, and any medications they may be on.

Obesity is primarily a disorder of insulin resistance, with knock-on effects to other hormones, fat storage and energy status in cells. Many people who are obese have just eaten the wrong diet, though other factors affect weight gain, such as medications, lifestyle, money (or lack of), social/work status, stress (physical and emotional) and yo-yo dieting.

Many other factors, such as lifestyle habits, socio-economic status, stress from anti-fat prejudice and discrimination, repeated weight loss attempts and weight cycling, can all play their part in a person becoming obese.  Unlike some sources which say obesity is an ED, I would say obesity is a result of various body systems going wrong than being an eating disorder in and of itself.


While orthorexia (lit, ‘correct diet’) is not listed as an official diagnosis in the Diagnostic and Statistical Manual of Mental Disorders it still can be a debilitating disease. Orthorexia is lesser known than AN and BN and is a bit more deceptive: it can often begin as a new life style of eating healthier and cleaner, but it can become an obsession, with the fixation on the types of food and ‘purity of food eventually leading to a sufferer’s health becoming compromised.

The Academy of Nutrition and Dietetics defines Orthorexia as ‘an unhealthy fixation on eating healthy or “pure” foods.’  This disorder is typically characterised by an extreme obsession with avoiding foods perceived to be harmful or unwholesome.

Unlike AN and BN, however, orthorexia sufferers are over-concerned more with the quality than quantity of food.  In addition, an orthorectic may want not so much to lose weight but to establish, though diet (partly or wholly), feelings of health, cleanliness, and pureness.

Orthorexia is becoming more common as more fad diets make their way into people’s consciousnesses. Instead of changing one’s diet to be a part of healthy living, a person with orthorexia obsesses with ‘wholesome eating’ to the point where health may become compromised.

Common orthorectic behaviours include:

  • Elimination of entire food groups in attempt for a ‘clean’ or ‘perfect’ diet
  • Thinking critically of others who do not follow strict diets, especially ones the an orthorectic believes is the right one (for that period of time, anyway – the idea of what is best can change)
  • Spending extreme amounts of time and money in meal planning and food choices
  • Obvious anxiety regarding how food is prepared, especially of someone else is making the meal
  • Avoidance of social events involving food for fear of being unable to comply with diet
  • Feelings of guilt or shame when unable to adhere to diet standards
  • Feeling fulfilled or virtuous from eating healthily… yet losing interest in other activities once enjoyed

An orthorectic can suffer physically, emotionally and mentally and, as the problem develops, it can mimic the effects we see in AN and BN, such as malnutrition, social isolation, and emotional instability.


This is a non-medical American term (but still worth including) to describe a combination of anorexia, bulimia and alcoholism whereby a person (usually a younger woman and not usually men) starves themselves throughout the day and then goes out at night and drinks to excess.

Despite the ‘exia’ part of the word, alcohol abuse is not strongly tied to anorexia as a person with AN tends to avoid alcohol consumption altogether both from a calorie and self-control point of view. People with BN, however, may also develop drunkorexia as it helps alter mind state and also facilitates purging by vomiting.

A person who relies alcohol as a sort of food can become malnourished and depressed and runs a high risk of becoming an alcoholic.



[1] This scale comes from the Minnesota Multiphasic Personality Inventory-2 (MMPI-2); it is composed of 50 statements that must be answered true or false as applied to self.

[2] Fairburn & Harrison, 2003; Turner & Bryant-Waugh, 2003; Ricca et al, 2001

[3] American Psychiatric Association, 1994

[4] A family with a psychiatric history or environmental stress factors can be implicated

[5] The BMI range varies for children depending on where they are on the age-height growth curve

[i][i] Arcelus J, et al. Mortality rates in patients with anorexia nervosa and other eating disorders. Archives of General Psychiatry, 68(7):724-731. Hudson JI, Hiripi E, Pope HG, Kessler RC. The prevalence and correlates of eating disorders in the National Comorbidity Survey Replication. Biological Psychiatry. 2007; 61:348-58.

[ii] Bulimia, anorexia nervosa, and anorexia nervosa with bulimia: A comparative analysis of MMPI profiles. Dennis K. et al.

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