Eating disorders: ARFID and medical complications

• Eating disorders are serious mental health conditions with physical complications; some of those complications can be life-threatening even when the person looks well and blood tests are normal.
• ARFID is a newer eating disorder: it involves avoidance or restriction of food without the body-image preoccupation seen in anorexia nervosa, often starts before 12 years of age ^[4], and can present at any weight.
• Binge eating disorder (BED) is the most common eating disorder in some adult settings; its first-line psychological treatments are binge-eating-focused guided self-help and cognitive behavioural therapy (CBT-ED), not dieting.
• Other specified feeding or eating disorder (OSFED) is the category for presentations that cause distress or impairment but do not meet full criteria for anorexia, bulimia or BED; treatment usually follows the closest matching diagnosis.
• Every very ill patient needs the same things first: an assessment of physical risk, correction of fluids and electrolytes, a careful refeeding plan with thiamine, and early multidisciplinary care. RCPsych's MARSIPAN guidance is now replaced by MEED ^[3].

By the end of this page you should be able to:

1. Define ARFID and explain how it differs from anorexia nervosa, bulimia nervosa and BED.
2. Recognise the medical complications of eating disorders, including those of ARFID, and where they occur across the weight spectrum.
3. Screen for, assess and risk-stratify an unwell person using the MEED traffic-light approach.
4. Outline a safe refeeding plan and describe refeeding syndrome and how to prevent it.
5. Choose and sequence treatment for BED, including group and individual CBT-ED and guided self-help.
6. Apply the OSFED principle and the NICE NG69 recommendations on compulsory treatment and pregnancy.

The DSM-5-TR classification used by the APA (2023) ^[2] groups these conditions into anorexia nervosa, bulimia nervosa, binge eating disorder (BED), avoidant restrictive food intake disorder (ARFID), pica, rumination disorder, and other specified or unspecified feeding and eating disorders. ICD-11 uses a broadly similar group of diagnoses. This page is about ARFID, BED and related unspecified presentations, with the medical complications that can follow any restrictive or chaotic eating pattern.

Anorexia nervosa is restrictive eating with low body weight, fear of weight gain and disturbance of body image. Bulimia nervosa is recurrent binge eating with compensatory behaviours such as vomiting, laxatives or excessive exercise. BED is recurrent binge eating without regular compensatory behaviour, causing marked distress. ARFID is avoidance or restriction of food intake that is not explained by lack of food or by a cultural practice, and is not driven by worry about body weight or shape.

ARFID has three common, overlapping motivations: little interest in food or poor appetite; avoidance based on the sensory qualities of food such as texture, smell, colour or temperature; and fear of the consequences of eating, for example choking, vomiting, pain or allergic reactions. ^[2] A diagnosis usually requires at least one of the following: marked weight loss or failure to gain expected weight; a significant nutritional deficiency; dependence on enteral feeding or oral nutritional supplements; or marked interference with psychosocial functioning. ARFID often begins in childhood, may present across the weight spectrum, and is often identified during paediatric rather than psychiatric encounters.

OSFED (other specified feeding or eating disorder) collects presentations that cause distress or impairment but fall short of full criteria. Common forms include atypical anorexia nervosa (all criteria except significantly low weight), bulimia nervosa of lower frequency, BED of lower frequency or duration, purging disorder, and night eating syndrome. The NICE NG69 recommendation for OSFED is simple and practical: consider using the treatments for the eating disorder it most closely resembles. ^[1]

Eating disorders are common and can arise at any age. They are not confined to young, female or underweight patients. ^[3] The risk of first presentation is highest for young people between 13 and 17 years of age. ^[1]

ARFID usually begins before 12 years of age ^[4]. Its estimated prevalence has been reported as 3.2% to 15.5% in primary-school-aged children and about 0.5% across all ages. ^[4] Surveys from clinical services report higher rates, because children who reach specialist clinics are not representative of all children with food avoidance.

Medical and psychiatric comorbidity is common in ARFID. Many children have gastrointestinal symptoms, feeding difficulties in infancy, or neurodevelopmental conditions. ^[4] In children and young people with ARFID, a systematic review found that 93 of 207 (44.9%) had at least one medical symptom associated with the eating disorder. ^[4]

Eating disorders arise from the interaction of biology, psychology and environment rather than from a single cause. Useful risk factors include:

• Biological vulnerability such as female sex for anorexia and bulimia, family history, genetics, early feeding difficulties and disorders such as diabetes mellitus (where eating and insulin can become entangled).
• Psychological factors such as perfectionism, anxiety, obsessive-compulsive traits, trauma, and distress around food, body image or control.
• Environmental factors such as social pressure about weight or shape, sport or dance demands, teasing, abuse, neglect, dieting, and major losses or transitions.
• Medical triggers such as gastro-oesophageal reflux, food allergy, painful swallowing, dental problems or surgery, which can make eating frightening and can start ARFID when the medical illness persists in altered eating patterns.
• Starvation effects when restrictive dieting has already begun, because malnutrition itself maintains rigidity, anxiety and preoccupation with food.

In ARFID the core problem is food avoidance or restriction. It may come from sensory sensitivity, low interest, or conditioned fear of aversive consequences. ^[2] In contrast to anorexia nervosa, patients with ARFID are not primarily restricting in order to control body shape or weight.

Prolonged undernutrition leads to adaptations that then create danger during recovery. In early starvation, blood glucose and insulin fall, glycogen is used, and metabolism shifts to fats and ketones. Intracellular stores of phosphate, potassium and magnesium become depleted, but blood concentrations can remain normal until feeding starts. ^[5]

Rapid reintroduction of carbohydrate triggers an insulin surge, driving glucose, phosphate, potassium and magnesium into cells. This produces fluid retention and sodium retention. The result is refeeding syndrome: hypophosphataemia, hypokalaemia and hypomagnesaemia, with cardiac, respiratory, neurological, haematological, gastrointestinal and musculoskeletal manifestations that can include death. ^[5]

Other mechanisms worth naming:

• Cardiovascular: starvation lowers resting metabolic rate. In severe cases bradycardia, hypotension, QT prolongation and cardiac arrhythmia occur.
• Bone: low body weight, delayed puberty, amenorrhoea and low oestrogen reduce bone mineral density, even when the person can appear healthy.
• Gut: functional dyspepsia, constipation, delayed gastric emptying and early satiety reinforce restriction.
• Brain: anorexia and bulimia alter reward and satiety signalling; anxiety around foods becomes conditioned.
• Medicines: malnutrition and purging alter drug absorption, metabolism, adherence and side-effect risk, so medication should never be the sole treatment. ^[1]

People with eating disorders describe fear of eating, early fullness, liking only a small range of foods, avoidance of social eating, repeated stopping and starting of diets, binge eating, guilt and secrecy. Children may say that foods make them feel sick or that certain smells or textures are unbearable. A patient with ARFID may say "I just do not feel hungry" or "I am frightened of choking", rather than "I want to be thin."

Physical assessment looks for starvation, purging and atypical or absent periods. The NICE NG69 identification list includes low or unusually high body mass index (BMI) or body weight for age, rapid weight loss, menstrual or other endocrine disturbance, unexplained gastrointestinal symptoms, poor circulation, dizziness, palpitations, fainting or pallor, vomiting or laxative or diet pill misuse, excessive exercise, atypical dental erosion, and abnormalities of blood pressure, pulse or ECG. ^[1]

Assess distress about shape and weight, the percentage of time preoccupied with food and body image, co-occurring depression, anxiety, obsessive-compulsive symptoms, self-harm, substance misuse, and suicidal ideation. Many people with ARFID do not show body-image distress, which is one of the clues that separates ARFID from anorexia nervosa. ^[2]

A review of physical complications in children and young people with ARFID found that these patients can present across the weight spectrum: many are in the healthy-weight to underweight range, but not all are underweight. ^[4] Most non-case studies found mean heart rates and blood pressures in the normal range for age, but 3.92% to 52.6% of young people with ARFID had bradycardia, and around 2% had hypotension. ^[4] Compared with anorexia nervosa, people with ARFID on average had higher heart rates despite similar levels of underweight. ^[4]

Electrolyte abnormalities have been reported in 23.1% to 73.7% of young people with ARFID, with hypokalaemia in 23.1% and hypophosphataemia in 7.7% in one study. ^[4] Rarely, hypokalaemia has been severe enough to cause rhabdomyolysis. ^[4]

Nutritional deficiencies are common: five studies found a high prevalence of children with ARFID not meeting the recommended intake for several micronutrients, and one study found that 67% of individuals with ARFID consumed less than 80% of the recommended intake of six or more micronutrients. ^[4] Severe micronutritional deficiencies have included iron deficiency anaemia, scurvy, rickets, nutritional optic neuropathy, Wernicke encephalopathy and severe osteoporosis. ^[4]

Bone mineral density can be low in ARFID; case series reported z-scores at or below minus 2 in most described cases, with a mean z-score of minus 2.46 in one study. Low bone mineral density was associated with lower BMI, delayed puberty and amenorrhoea, but severe osteoporosis has also occurred in boys of healthy body weight. ^[4]

Puberty and menstruation are affected less often in ARFID than in anorexia nervosa with similar degrees of underweight; amenorrhoea has been reported in around 10% of females with ARFID. ^[4] A systematic review found no published mortality analyses for ARFID in the literature it captured, but malnutrition is potentially fatal. ^[4]

The first distinction is usually clinical: does the person have body-image-driven restriction (anorexia), binge-purge cycles (bulimia), binge eating without compensation (BED), or food avoidance without body-image concern (ARFID)? Comorbid anxiety, obsessive-compulsive disorder, gastro-intestinal illness, diabetes and autism or ADHD can all look like ARFID.

Medical mimics of weight loss and restriction include celiac disease, inflammatory bowel disease, malignancy, hyperthyroidism, diabetes mellitus, Addison disease, infection, and malabsorption. Eating disorders can also coexist with these conditions, so a normal-looking illness does not exclude medical disease.

Baseline assessment should be routine rather than waiting for a crisis. NICE NG69 supports assessing physical health, including the effects of malnutrition, electrolyte imbalance and ECG need. ^[1]

Recommended initial work-up:

• Height and weight history including lowest and highest weights and recent change.
• BMI for age in children, or percent median BMI, BMI percentile or Z-score; track trends, not single values.
• Fluid and electrolyte balance where compensatory behaviours such as vomiting, laxative or diuretic use, or water loading are present. ^[1]
• Laboratory tests: complete blood count and comprehensive metabolic panel including electrolytes, liver enzymes and renal function; the APA recommends these as part of the initial laboratory assessment. ^[2]
• An ECG in restrictive eating, severe purging behaviour, or when taking medicines that prolong QTc. ^[2][1]
• Nutritional profile where possible: iron studies, vitamin D, B12, folate, thiamine, zinc, and thyroid function when clinically indicated.
• Bone mineral density by dual-energy X-ray absorptiometry when a threshold is met (below).
• Screening for comorbid conditions: depression, anxiety, obsessive-compulsive disorder, diabetes, gastrointestinal disease.

Instead of one severity score, most practice combines diagnosis with risk. The following points are useful:

• BMI alone does not determine severity or need for admission. NICE specifically warns against using an absolute weight or BMI threshold when deciding on inpatient or day-patient care; the trend and rate of loss matter as much as the number. ^[1]
• Low bone mineral density should usually be investigated after about 1 year of underweight in children and young people, or 2 years in adults, and earlier with bone pain or recurrent fractures; repeat scans no more than once yearly unless new symptoms appear. ^[1]
• ECG if there is rapid weight loss, excessive exercise, severe purging, bradycardia, hypotension, excessive caffeine, medicines or muscular weakness. ^[1]
• Bone protection: reaching and maintaining a healthy body weight or BMI for age is the main treatment for low bone mineral density. Hormonal treatments are reserved for specific situations in adolescents and bisphosphonates for adults with long-term low weight and low bone mineral density, after specialist advice. ^[1]

ARFID criteria should be paraphrased from DSM-5-TR as summarised by the APA: an eating or feeding disturbance with avoidance or restriction of food; one of the four consequences listed above; and exclusion of body-image-driven restriction, culturally related practice and food scarcity. ^[2]

Management for eating disorders is multidisciplinary by default: medical, psychiatric, psychological and nutritional expertise, commonly in a coordinated team. ^[2]

Provide acute medical care, including emergency admission, when there is severe electrolyte imbalance, severe malnutrition, severe dehydration, or signs of organ failure. ^[1] People with an eating disorder whose physical health is severely compromised should be admitted to a medical or day-patient service for medical stabilisation and refeeding when these cannot be done safely as an outpatient. ^[1]

MEED (Medical Emergencies in Eating Disorders) is RCPsych's current guidance. It replaces the earlier MARSIPAN and Junior MARSIPAN guidance, provides summary sheets for different professional groups, and includes a traffic-light risk assessment applicable to all ages. ^[3] MARSIPAN is therefore still a useful historical term, but MEED is the current risk framework.

The MEED checklist uses a traffic-light approach. In its assessment step, three screening questions are asked: does the person have an eating disorder? Is the person medically compromised? Is the person consenting to treatment? ^[3] Medically compromised warning criteria include:

• very low weight: BMI below 13 in adults, or below 70% of median BMI in under-18s; ^[3]
• recent weight loss of more than 1 kg per week for 2 consecutive weeks; ^[1][3]
• acute food or fluid refusal below 400 kcal per day; ^[3]
• pulse rate below 40 beats per minute when awake; ^[3]
• postural drop or dizziness suggesting hypotension;
• core temperature below 35.5 degrees C; ^[3]
• abnormal ECG;
• sodium below 130 mmol per L, potassium below 3 mmol per L, glucose below 3 mmol per L, raised transaminases, or raised urea or creatinine. ^[3]

Refeeding must be protocol-driven and should avoid both under-nutrition and refeeding syndrome. NICE NG69 recommends using a standard operating procedure that emphasises this balance and refers to MEED. ^[1] MEED also provides a separate refeeding syndrome risk assessment with the following risk items: abnormal electrolytes; life-threatening systemic disease; peripheral oedema or acute circulatory fluid overload; BMI below 13; weight loss of 1 kg per week or more; calorie intake below 500 kcal per day for 4 or more days; and significant alcohol misuse above 14 units per week. ^[3]

International refeeding experience shows wide variation, especially between cautious European and Australian practice and more rapid American practice. Reviews report initial calorie provision ranging from 5 to 20 kcal per kg per day up to 30 to 40 kcal per kg per day, with gradual increases of 5 to 10 kcal per kg per day in high-risk patients or 10 to 20 kcal per kg per day in moderate-risk patients, rising later to 70 to 100 kcal per kg per day when energy requirements are higher. ^[5] A common protocol table advises prophylactic thiamine 200 to 300 mg, multivitamin replacement, sodium restriction below 1 mmol per kg per day in higher-risk patients, fluid restriction 20 to 25 ml per kg per day in very high risk and 25 to 30 ml per kg per day in high risk, and cautious nutritional support for several days before progression. ^[5]

Nutritional support, by whatever route is chosen, should start cautiously and increase gradually. ^[5] Electrolytes should be supplemented prophylactically, and hypophosphataemia, hypokalaemia and hypomagnesaemia monitored. Phosphate may be given before starting feeds even when blood levels are low-normal in at-risk patients. ^[5] Thiamine should be given before refeeding even when blood levels are normal. ^[5] Parenteral nutrition is only used when no other route is possible. ^[5] Enteral feeding, through nasogastric feeding if needed, is an established route for higher calorie requirements. ^[5]

If guided self-help is unacceptable, contraindicated or ineffective after 4 weeks, offer group CBT-ED for adults with BED: typically 16 weekly 90-minute group sessions over 4 months, with psychoeducation, self-monitoring, food intake planning and relapse prevention. ^[1] If group CBT-ED is unavailable or declined, consider individual CBT-ED, typically 16 to 20 sessions. ^[1]

The APA Practice Guideline (2023) similarly recommends eating disorder-focused CBT or interpersonal therapy for BED, in individual or group formats, and suggests either an antidepressant or lisdexamfetamine for adults who prefer medication or have not responded to psychotherapy alone. ^[2] NICE states that medication should not be the sole treatment for BED, anorexia nervosa or bulimia nervosa. ^[1]

BED treatment principles:

• Explain that weight loss is unlikely to be the main outcome of psychological therapy.
• Teach regular planned eating, self-monitoring of binge eating and cues, and coping with triggers.
• Address body-image concerns if present.
• Include family and carers in children and young people.
• For children and young people, offer the same treatments recommended for adults. ^[1]
• Integrate with diabetes teams where diabetes is present; avoid rapid insulin dose increases. ^[1]

No guideline has treatment recommendations for ARFID based on clinical trials; the APA (2023) states that its systematic review found no rigorous trial data, although it discusses ARFID assessment and treatment planning. ^[2] This means ARFID care should be individualised, conservative and collaborative:

• Nutritional rehabilitation and growth support under a dietitian.
• Gradual reintroduction of foods using graded exposure, food chaining or sensory-based steps where developmentally appropriate.
• Assessment and treatment of medical causes such as reflux, eosinophilic oesophagitis, inflammatory bowel disease or dental pain.
• Supportive caregiver work, because families are usually central to change in children.
• Multidisciplinary teams for children with neurodevelopmental conditions, gastrointestinal illness or enteral dependence.
• Medical stabilisation where there is rapid weight loss, electrolyte disturbance or dehydration.
• Family-based or cognitive methods may be used, but the choice should reflect evidence quality, family preferences and comorbidity rather than brand name.

For OSFED, use the treatment for the eating disorder it most closely resembles. ^[1] This means atypical anorexia nervosa is usually treated with anorexia-focused care even when weight is not significantly low; purging disorder with bulimia-focused care; low-frequency BED with binge-eating-focused care. Avoid minimising the illness simply because full criteria are not met.

NICE NG69 recommends regular dental and medical reviews for people who vomit, advising against brushing teeth immediately after vomiting, rinsing with non-acid mouthwash, and avoiding highly acidic foods and drinks. ^[1] People who misuse laxatives or diuretics should be advised that these do not reduce calorie absorption and do not help weight loss, and should be supported to reduce use gradually. ^[1] People who exercise excessively should be advised to stop. ^[1] Bone mineral density is assessed, explained and monitored as above, and transdermal 17-beta-estradiol or bisphosphonates may be considered in selected long-term cases after specialist advice. ^[1]

For people not under treatment or who decline treatment, low-risk patients can be discharged to primary care with freedom to return; high-complexity patients need continued support. ^[1] If physical health is at serious risk, the person does not consent, and treatment can only happen safely as an inpatient, compulsory treatment under the relevant legal framework is used. ^[1] Feeding without consent must only be done by competent multidisciplinary teams. ^[1]

The medical complications of eating disorders include:

• Refeeding syndrome (hypophosphataemia, hypokalaemia, hypomagnesaemia, and thiamine deficiency) with cardiac, respiratory, neurological, haematological, gastrointestinal and musculoskeletal complications, including death. ^[5]
• Cardiac: bradycardia, hypotension, prolonged QT interval, arrhythmia, reduced cardiac output and heart failure.
• Nutritional: low weight, dehydration, micronutrient deficiencies and anaemia.
• Bone: low bone mineral density, stress or overt fractures, short stature in children.
• Endocrine: delayed puberty, amenorrhoea, fertility disturbance and hypo-oestrogenism.
• Gastro-intestinal: epigastric pain, reflux, constipation, delayed gastric emptying and refeeding ileus.
• Oral and renal: dental erosion, renal impairment, electrolyte disturbance.
• Neurological: confusion, seizures in severe hyponatraemia or refeeding, Wernicke encephalopathy.
• Psychological: self-harm, depression, anxiety, social impairment and suicide risk.
• ARFID-specific: across-weight presentations with bradycardia in a minority, hypotension, severe nutritional deficiencies, low bone mineral density and growth faltering. ^[4]

Prognosis improves with early, specialist treatment. Long-standing undernutrition and repeated readmission worsen outcomes. Inpatient treatment alone does not cure an eating disorder: weight restoration and psychological recovery need continued outpatient care after discharge.

Screen for eating disorders as part of an initial psychiatric evaluation. ^[2] Screening tools such as SCOFF should not be used as the sole test. ^[1] Identify high-risk groups: young people aged 13 to 17, elite sport, dance, fashion, diabetes mellitus, and chronic illness affecting diet. ^[1] Early treatment is particularly important for those with or at risk of severe emaciation. ^[1]

Prevention is not only about weight: it includes reducing stigma and bullying, supporting healthy media use, spotting eating pattern changes, and giving early nutritional and psychological help before behaviour becomes entrenched.

Children and young people. Watch for faltering growth, delayed puberty and age-adjusted BMI, growth charts and ECG. Use age-appropriate facilities close to home with educational support during extended admissions. Consider family-based therapy for anorexia and bulimia nervosa. ^[1]

Pregnancy. Women with eating disorders need support to conceive and carry healthy pregnancies; pregnant women need monitoring for psychological and physical risks and may need a dedicated named professional for support. ^[1]

Diabetes. Eating disorders and diabetes need collaboration between diabetes and eating disorder teams, more frequent glucose and ketone monitoring, gradual carbohydrate and insulin changes, and treatment of insulin misuse as part of psychological care. Avoid rapidly correcting high blood glucose because retinopathy and neuropathy risk increases. ^[1]

Older adults and low-resource settings. People of any age, including older adults, can have eating disorders. In low-resource settings, clinical assessment, weight trend, heart rate, lying and standing blood pressure, temperature and an ECG may be available even when specialist services are not. Oral thiamine and multivitamins are low cost; senior clinical support and a dietician should guide feeding. Refer early when there is severe electrolyte disturbance, organ failure, very low weight or non-consenting serious risk.

• A transthoracic echocardiogram and ECG may be scarce; rely on repeated clinical observations, postural signs and nearby referral.
• For ARFID, detailed feeding histories and dietetic support are more useful than expensive tests.
• Oral supplements and family-meal pacing can be organised even when inpatient beds are unavailable.
• When local compulsory-treatment facilities are absent, transfer early to a centre that can manage medical and psychiatric risk.

Depression, anxiety disorders, obsessive-compulsive disorder, diabetes mellitus type 1, gastro-oesophageal reflux disease, inflammatory bowel disease, coeliac disease, osteoporosis, autism spectrum conditions, attention deficit hyperactivity disorder, and self-harm.

• Eating disorders can be medically dangerous independent of whether a person is underweight.
• ARFID is food avoidance or restriction without body-image drive, often beginning before age 12, and may affect children at any weight.
• Binge eating disorder is treated primarily with binge-eating-focused guided self-help and CBT-ED, not dieting.
• OSFED should be treated like the closest matching eating disorder.
• NICE NG69 does not use a single BMI threshold for admission; rate of weight loss, vital signs and ECG matter.
• The MEED traffic-light risk assessment replaces MARSIPAN and applies to all ages.
• Refeeding syndrome is hypophosphataemia, hypokalaemia and hypomagnesaemia triggered by refeeding; thiamine, electrolytes and graded calories reduce risk.
• ARFID carries cardiovascular, electrolyte, micronutritional, bone and growth complications, sometimes at healthy weight.
• Medication should not be the sole treatment for an eating disorder.
• Compulsory treatment is reserved for serious physical risk without consent, and feeding without consent requires a competent multidisciplinary team.