Eating disorders
Eating disorders are severe medical conditions centred on energy intake and sometimes on body dissatisfaction. They are the extreme end of a spectrum of eating behaviour that runs from healthy eating through disordered eating, and diagnostic clinical criteria identify them. They go largely undetected, so their prevalence estimates may be low, and the stigma that diet culture feeds shapes how they are seen and diagnosed. The brain and the gut might contribute to their signs and symptoms. Writing about them serves three readerships, each short of accurate information: treatment teams, physicians and the lay public.
The spectrum from healthy eating to eating disorders
Eating behaviour sits on a spectrum with healthy eating at one end. The US government defines healthy eating as the daily consumption of a variety of nutritious foods and drinks with mindfulness about overeating or undereating. Healthy eating is typically defined as fulfilling the body's homeostatic needs while keeping a flexible diet. Meeting those needs is one component of healthy eating, and a second is a person's relationship with food: enjoying the foods one eats, not attaching values to foods, as in labelling some forbidden, and keeping a flexible diet are further aspects of it.
Disordered eating lies next along the spectrum, and the transition to it is not clearly defined. The transition can occur when a person's eating does not fulfil the body's homeostatic needs, as in restrictive eating or overeating, and disordered eating also occurs when a person feels guilt or shame for eating. Healthy eating becomes disordered when a person does one or more of the following: restricts food, limits specific foods, eats beyond satiation, feels guilt after eating, keeps an inflexible diet or is nervous eating in public. Under that definition, many accepted eating habits, such as a low-carbohydrate diet, can count as disordered eating. Disordered eating is not necessarily harmful, but it becomes a concern when it impairs a person's physical health and quality of life. Addressing it matters because, left untreated, it could progress to an eating disorder. Eating disorders are extreme versions of disordered eating, identifiable by diagnostic clinical criteria. They have a severe, lasting effect on the body and brain, such as heart and gastrointestinal irregularities. They are a group of severe medical conditions that centre on energy intake and sometimes on body dissatisfaction.
Diagnostic criteria
The eating disorders, and the features that define each:
- Anorexia nervosa: restricting daily energy intake in ways that interfere with the body's appropriate developmental trajectory, together with an intense fear of weight gain, disturbed body perception and denial of the severity of the low weight.
- Bulimia nervosa: recurrent binge eating, at least once a week for 3 months, with body disturbance and compensatory behaviour to prevent weight gain, such as vomiting; a binge is uncontrollably eating an atypically large amount of food in a short period.
- Binge eating disorder: recurrent binge eating, at least once a week for 3 months, with a binge defined the same way; eating until uncomfortably full and distress about the bingeing might also be present.
- Avoidant restrictive food intake disorder: a lack of interest in food that results in nutritional and energy deficits, with no body-image disturbance and no separate medical condition to which the restrictive eating can be attributed.
- Pica: persistent eating of nonedible substances, such as soil, paper or chalk, for at least 1 month, the substances not being culturally supported.
- Orthorexia: an obsession with healthy eating that impairs well-being, not officially recognised as an eating disorder by the American Psychiatric Association as of 2023 but acknowledged as one by clinicians and the public.
- Subclinical eating disorder: extreme disordered eating in someone who does not meet every criterion for a diagnosis, which can damage health and well-being although as of 2023 the American Psychiatric Association does not officially recognise it.
Diet culture and stigma
Definitions of eating behaviour can be fluid and vague, and so are often inconsistent within health communication. Diet culture is an example of this fluidity. It attaches values to foods and lifestyle practices, as in celery being a good food, and people accept these beliefs and follow them ritualistically to achieve thinness, which diet culture equates with health, morality and increased social status. Because diet culture limits what a person can eat and fixates on weight loss, its practices can be considered disordered eating. Dieting, however, is rarely considered disordered eating and has become normalised as a type of healthy eating through diet culture's communication. Normalising disordered eating minimises the seriousness of eating disorders and influences how people think and feel about food, how they eat and how they relate to their bodies.
The normalisation of eating disorder behaviour, such as food restriction, in diet culture has contributed to the stigmatisation of eating disorders. The most prevalent stigmas include personal responsibility for the illness, as in the belief that people with eating disorders are vain; attention-seeking, as in the belief that they are not truly sick; and weakness, as in the belief that people with binge-type eating disorders are too lazy or weak to lose weight through diet and exercise. People with eating disorders are consequently often blamed for their illness and might internalise the blame. Internalised blame might lower self-esteem, hope and empowerment during treatment, which could prolong illness and decrease quality of life. For example, women with anorexia nervosa who feel stigmatised through personal responsibility for their eating disorder have a longer duration of illness, lower self-esteem and more severe symptoms than women who feel less stigmatised. Stigma can also foster negative reactions toward the illnesses in medical settings, leading to their underdiagnosis.
Prevalence and underdiagnosis
The point prevalence of eating disorders across subtypes has been estimated at 8.8% in adults and 5.7% in adolescents, with a higher lifetime prevalence in women than in men (8.4% against 2.2%). In children aged 9 and 10, the lifetime prevalence across subtypes has been estimated at 10%. Eating disorders have historically been misconceived as occurring mainly in White, heterosexual, cisgender people. Emerging research, however, shows that Native American or Alaska Native women and Black women are as likely as White women to meet criteria for an eating disorder and more likely than White women to develop binge eating disorder. LGBTQIA+ populations are likewise at elevated risk, often with higher rates of eating disorder behaviours than cisgender or heterosexual people. These estimates could be low and inaccurate, because eating disorders go largely undetected by medical professionals in people of all ages and groups. One reason for the underdiagnosis could be the normalisation of disordered eating in diet culture.
The brain and the gut
Atypically high levels of brain serotonin could contribute to the restrictive eating, anxiety and cognitive inflexibility of anorexia nervosa, whereas atypically low levels could explain the compulsivity, impulsivity and binge eating of bulimia nervosa and binge eating disorder. On that evidence, selective serotonin reuptake inhibitors have been used, with limited effectiveness, to rebalance serotonin and reduce symptoms associated with eating disorders, such as depression. It is unclear whether serotonin imbalances are present before an eating disorder begins, for example as the result of genetic variants, or emerge in response to disordered eating, such as starvation or excessive carbohydrate intake.
How the brain constructs body image during an active eating disorder might also explain signs and symptoms. Body image describes how a person perceives and feels about their body. The construct a person builds from those perceptions and feelings influences the third-person image of themselves they keep in long-term memory for self-reference, so it might not accurately represent how they appear to others. The brain nonetheless works to make the construct as accurate as possible by updating it daily with current sensory information, such as seeing one's reflection, and these daily updates are how the mental self-representation changes as weight fluctuates. In anorexia nervosa, the brain might not update the construct after weight changes because short-term memory processing is disrupted, which could explain why severely underweight people with the illness insist that they are overweight. Potential causes of the disruption include, but are not limited to, stress and social influence, such as media images of idealised bodies. Whether the disruption is present before anorexia nervosa begins or emerges in response to the illness is unclear. People with anorexia nervosa also have reduced connectivity between brain regions responsible for estimating body size and shape, such as the extrastriate and fusiform body areas, and so estimate their body dimensions erroneously. Body image therapy has been shown to increase the connectivity between those regions, making the estimates of body dimensions more accurate in people with anorexia nervosa.
Dysfunction in gut–brain interactions might also contribute to signs and symptoms. Disorders of gut–brain interaction, such as dyspepsia, are common among people with avoidant restrictive food intake disorder, possibly because gastrointestinal discomfort contributes to food avoidance. In those cases the eating disorder likely develops in response to the gut disorder, and treating the gut disorder could reduce the eating disorder's signs and symptoms. Dysbiosis also plays a role in eating disorder signs and symptoms. In anorexia nervosa, bacterial imbalances in the gut microbiome could contribute to reduced appetite, depression, anxiety and difficulty gaining weight. For example, germ-free mice given faecal microbes from women with the illness ate less, gained weight with difficulty and showed more anxiety-like and compulsive behaviour than control mice. How these imbalances contribute to the outcomes is unclear. Increased gut permeability during an active eating disorder might also alter the immune system in ways that contribute to the pathology, as with cytokines decreasing appetite. Whether atypical gut composition or permeability develops before an active eating disorder, during one, or both, is unclear.
Eating disorders in medical communication
Eating disorders have a weak presence in medical communication, although the illnesses involve and affect nearly every organ in the body. Information articles on eating disorders have largely been absent from medical communication. One reason could be that eating disorders are not considered serious medical conditions. Unlike for other illnesses, few drugs have been effective in reducing their symptoms, and treatment has centred on psychotherapy and behavioural therapy instead. That emphasis on therapy might perpetuate the belief that the illnesses are solely psychological. The omission of eating disorders from medical communication needs to change.
Information about eating disorders has been particularly inaccurate, omissive and exaggerated in health communication, which has resulted in their ongoing stigmatisation. Despite their severity, lay people and health professionals often view eating disorders negatively. Medical writers, as health educators, are positioned to challenge and change these stigmas by creating and distributing accurate information. The absence of eating disorders from medical communication may have contributed to ongoing misinformation about them and to the negative attitudes that lay people and health professionals hold about them. The pervasiveness of the stigmas makes now a good time for medical writers to understand these conditions more deeply, so as to reframe the narrative and reform attitudes toward them by creating informed, nonjudgmental and accessible content.
Writing about the brain's role in eating disorder signs and symptoms is one way medical communicators could reduce the stigma among the public and health professionals, by de-emphasising personal responsibility for the behaviour. Research shows that enhancing discussions about eating disorders with biological information, rather than strictly sociocultural information, improves people's attitudes toward these illnesses. Including neuroscience information in communication about eating disorders could improve understanding of them and potentially reduce their stigmatisation.
Writing for the treatment team
Recovery from an eating disorder requires a treatment team of health professionals, such as physicians, dieticians and psychologists, so reducing the stigmas and improving eating disorders education in medical settings is important. Members of the team often lack specialised knowledge of eating disorders, which can slow communication between them and interfere with treatment decisions. Medical writers could therefore help the team communicate by providing clear and accurate educational information. Effective communication within the team is crucial to a patient's recovery: the longer an eating disorder persists, the more treatment-resistant it becomes and the more it damages the brain and body, as in heart and gastrointestinal conditions.
Writing for physicians
Educational content about eating disorders for health professionals could also help prevent these illnesses. Physicians often overlook the warning signs of an eating disorder, particularly in children and athletes, because of miseducation about the disorders or not taking them seriously. Recognising the signs in children matters because eating disorders increase susceptibility to injury and affect growth, brain development and immune response. Physicians therefore need a fuller understanding of eating disorders and disordered eating, specifically of early warning signs such as lanugo body hair growth, common medical complications such as a slow heart rate, biochemical markers such as low potassium levels, how to stabilise a patient with a chronic eating disorder safely, and how to define recovery.
Writing for lay readers
Medical writers can help destigmatise eating disorders among the public by interpreting emerging research about them for lay readers. Important topics to write about include the underlying biology, emerging treatments, eating disorders specific to populations such as particular genders and ages, their health consequences, obscure eating disorders such as avoidant restrictive food intake disorder, and recognising subclinical behaviour such as inflexible eating. A challenge in writing about eating disorders for nonexperts is to acknowledge the limitations of the available information while keeping credibility and authority. Meeting it requires dispelling earlier misconceptions about eating disorders and embracing the complexity of a science still evolving.