Educational draft · awaiting clinical reviewThe full textbook explains uncertainty but does not replace live national or local guidance, specialist advice, or current prescribing information.
Eating disorders in men, athletes and diverse populations
Psychiatry · UK scope · Sources checked 27 Aug 2026 · Clinical review pending
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Hidden restriction with physiological collapse
A muscular man, larger-bodied person, athlete, trans person or older adult may have rapid loss, severe restriction, purging, hypoglycaemia, bradycardia, electrolyte disturbance, fracture or acute suicide risk despite not matching a familiar eating-disorder image.
Action: Assess ABCDE, glucose, postural observations, temperature, ECG and indicated bloods, stop unsafe exercise, obtain urgent medical and specialist eating-disorder advice, and choose care from physiological and psychiatric risk rather than appearance, sex, identity, sport status or current BMI.
Overview
Recognise eating disorders and low energy availability beyond stereotyped presentations, use inclusive and culturally responsive assessment, identify sport-related medical harm, and remove weight, sex, gender, ethnicity, age or disability barriers to specialist care.
Diagnostic stereotypes create measurable clinical risk. A person may not volunteer an 'eating disorder' because their concern is athletic performance, muscularity, gastrointestinal discomfort, sensory overload, gender dysphoria, food affordability or fear of being judged. Begin with neutral questions about a usual day of eating, recent change, rules, excluded foods, bingeing, vomiting, medication or supplement manipulation, exercise, recovery, body checking and functional impact. Ask what the behaviour achieves and what feels threatening about change.
Men and boys can develop every eating disorder. Thinness-focused questions may miss a drive for a lean and muscular body, compulsive training, alternating bulking and cutting, or use of protein products, fat-loss agents and anabolic-androgenic steroids. Assess endocrine and sexual symptoms without relying on amenorrhoea: reduced libido, fewer spontaneous erections, fatigue, poor concentration, injury and stalled growth can reveal undernutrition.
Practice
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PsychiatryOriginal SBA
Higher-weight restrictive illness
A man with a BMI of 28 has lost 18% of his body weight rapidly through severe restriction and compulsive exercise and now has postural dizziness. What is the best response?
Sources and review status6 sources · checked 27 Aug 2026 · clinical review pending+
Sources
Sources and review status
National guidance is shown before implementation-dependent detail. Apply principles in context and verify current guidance when a decision affects care. Source check completed 27 Aug 2026; clinical approval remains outstanding.
Editorial contact: Doctor’s Passport editorial team. Source-check date is separate from clinical approval. Report a content problem ·
Do not
presume an athletic resting pulse is benign when accompanied by restriction, loss, syncope or poor perfusion.
RED-S describes health and performance consequences of low energy availability, when dietary energy remaining after exercise is insufficient for normal physiological function. Effects can involve reproductive and metabolic hormones, bone, immunity, gastrointestinal function, cardiovascular and haematological health, mood, cognition, injury and training response. Weight may be stable because the body adapts. Assessment therefore combines intake and training history, trajectory, symptoms, examination, bloods and injury pattern; no single laboratory test confirms or excludes the syndrome.
Sport culture can both obscure and amplify illness. Coaches may praise loss, select by weight or normalise pain and menstrual disturbance, while the athlete fears loss of place, scholarship or identity. Explain confidentiality and its safety limits, identify conflicts of interest and place health decisions with appropriately skilled clinicians. Medical instability, significant energy deficiency or stress injury may require temporary training modification or cessation, followed by staged return based on recovery rather than a calendar date.
LGBTQ+ people may face minority stress, bullying, body scrutiny or attempts to change body shape, but identity itself is not an aetiology. Ask rather than infer how gender, dysphoria, hormones or social safety interact with eating. Use the person's name and pronouns, discuss relevant anatomy and fertility sensitively, and coordinate eating-disorder and gender-affirming care so one service does not make recovery conditional on abandoning the other.
Culture and structural circumstances shape expression and access. Religious fasting, vegetarian eating and culturally specific foods are not pathological in themselves; assess whether practice changed, became rigid, causes impairment or is used to conceal restriction. Food insecurity may make a meal plan impossible, while racism and clinician bias can delay recognition. Offer trained interpreters, adapt written materials and include culturally familiar affordable foods. Avoid using relatives as interpreters for questions about purging, abuse, sexuality or coercion.
Neurodevelopmental and disability adaptations should change delivery, not lower therapeutic ambition. Sensory differences, interoceptive uncertainty, routine dependence and literal communication may contribute to ARFID or complicate another eating disorder. Agree predictable appointments, concrete language, visual meal plans, tolerable food changes and accessible weighing. For people in larger bodies, avoid congratulating rapid loss, moralising food or prescribing restriction before assessing eating-disorder risk.
Key points
Eating disorders occur in every sex, gender, age, ethnicity, socioeconomic group and body size; ask about behaviour and consequences rather than waiting for a stereotyped appearance.
Atypical anorexia can cause serious starvation physiology after substantial loss while weight remains above the low range; BMI is neither a referral gate nor a severity score.
In men and boys, enquire about muscularity concerns, leanness, supplements, anabolic-androgenic steroids, bulking and cutting, body checking and compulsive resistance or endurance exercise.
Relative energy deficiency in sport is impaired physiological functioning from problematic low energy availability; it affects male and female participants at any ability level and may be intentional or unintentional.
RED-S and an eating disorder overlap but are not synonyms: an athlete can be underfuelled without weight or shape psychopathology, and an eating disorder can exist without organised sport.
Trans and gender-diverse people need respectful names, pronouns and anatomy-specific care; explore dysphoria or weight manipulation without treating identity as pathology or a reason to withhold affirming care.
Cultural food practices, religious fasting and shared meals require curious assessment in context; use an independent professional interpreter for sensitive history when language support is needed.
Aetiology
01
Performance and body pressures
Selection, weight categories, aesthetic ideals, muscularity norms and praise for loss can reinforce restriction, compensation and concealment.
02
Minority and structural stress
Discrimination, dysphoria, poverty, food insecurity and unsafe environments may interact with vulnerability without making identity itself pathological.
03
Neurodevelopmental differences
Sensory processing, interoception, predictability needs and focused interests can shape food avoidance, rigidity and response to standard treatment delivery.
04
Life-course transitions
Puberty, sport progression, migration, pregnancy, menopause, bereavement, illness and ageing can expose or reactivate eating-disorder mechanisms.
Pathophysiology
1
Low energy availability
Insufficient dietary energy after activity causes adaptive suppression across endocrine, bone, immune, cardiovascular, haematological and metabolic systems.
2
Starvation at any size
Rapid energy deficit produces circulatory, cognitive and electrolyte risk before a person's weight crosses a population low-BMI boundary.
3
Exercise reinforcement
Training can temporarily reduce anxiety or earn social approval, strengthening compulsive movement despite injury, fatigue and physiological decline.
4
Diagnostic invisibility
Stereotypes alter clinician questions and patient self-recognition, delaying referral until behaviours and medical harm become more entrenched.
Clinical features and red flags
Muscularity-oriented presentation
Rigid training, checking, supplement or steroid use and distress about insufficient leanness or muscle may replace a stated wish to be thin.
Relative energy deficiency
Fatigue, impaired recovery, recurrent illness, low libido, menstrual disturbance, bone stress injury and declining performance cluster around chronic underfueling.
Higher-weight starvation
Substantial rapid loss, cold intolerance, dizziness, bradycardia and cognitive change can occur while BMI remains normal or high.
Culturally shaped disclosure
Symptoms may be expressed through digestion, purity, fasting, family food practice or somatic distress rather than familiar weight-language.
Neurodivergent eating needs
Sensory aversion, routine dependence, low interoceptive awareness and communication difference can shape restriction and the accessibility of standard therapy.
Later-life presentation
New restriction, recurrence, bereavement, frailty, dentition, dysphagia, medication and medical disease may interact in an older adult.
Red flags requiring action
Rapid weight loss, very low intake or recurrent collapse is dangerous at any starting weight; normal-range or high BMI must not delay medical assessment or referral.
Syncope during exercise, chest pain, unexplained bradycardia, reduced performance, recurrent stress injury or impaired recovery may signal low energy availability rather than healthy athletic adaptation.
Investigations
01Inclusive eating and body historyFirst step
Why
Elicit restriction, bingeing, purging, muscularity, dysphoria, sensory needs, food access and cultural meaning.
Interpretation and limitations
The individual's pattern determines formulation; absence of thinness language or low BMI does not exclude serious illness.
02Training and energy inventory
Why
Map sport sessions, occupational activity, rest, recent load, injury, intake timing and performance trajectory.
Interpretation and limitations
A persistent mismatch with systemic symptoms supports low energy availability, although reported calories alone are imprecise and not diagnostic.
03Physical and endocrine assessment
Why
Check trajectory, growth, postural observations, temperature, perfusion, strength, puberty, libido and menstrual or sexual function as relevant.
Interpretation and limitations
Select measures by age and anatomy without assuming sex or gender; physiological compromise determines urgency at any body size.
04Laboratory and ECG assessment
Why
Investigate glucose, electrolytes, phosphate, magnesium, blood count, renal, liver, thyroid and other clinically indicated endocrine markers.
Interpretation and limitations
Normal tests can coexist with RED-S or an eating disorder; abnormalities help determine acute risk and alternative diagnoses.
Differential diagnosis
01
Non-disordered underfueling
Inadequate sport nutrition, finances, schedule or knowledge can cause RED-S without weight-shape psychopathology, though an eating disorder may emerge or coexist.
02
Endocrine or systemic disease
Thyroid, pituitary, gastrointestinal, inflammatory, malignant and infectious disease can cause loss, fatigue and endocrine change requiring parallel investigation.
03
Substance or supplement effects
Stimulants, anabolic-androgenic steroids, thyroid products, diuretics and unregulated supplements can change appetite, mood, electrolytes and endocrine markers.
04
Culturally normative practice
Shared fasting or food restriction without secretive escalation, distress or impairment differs from pathology but still needs safety planning when medically vulnerable.
05
Primary feeding difficulty
Dysphagia, dentition, sensory-based ARFID, dementia and medication effects can restrict intake without shape concerns and require adapted multidisciplinary care.
Management
01Universal assessmentAsk beyond the stereotypeFirst stepEating, weight, body, exercise or unexplained physiological symptoms raise concern in any patient.+
1Use neutral questions about intake, rules, bingeing, compensation, exercise, supplements, body goals, trajectory and function without presuming sex, identity or motive.
2EscalationComplete physical and psychiatric risk assessment, including postural observations, ECG or bloods when indicated and same-day escalation for medical or suicide danger.
3Refer promptly to an age-appropriate eating-disorder service when suspected; do not wait for a low BMI or a culturally familiar presentation.
02Athlete pathwayProtect health before performanceAn athlete or highly active person has restriction, low-energy symptoms, injury, endocrine change or falling performance.+
Complications
01
Delayed recognition
Stereotype-driven reassurance permits further weight loss, purging, injury and psychiatric deterioration before appropriate specialist treatment begins.
02
Bone and endocrine harm
Persistent low energy availability impairs reproductive hormones and bone remodelling, increasing stress fracture, osteoporosis and fertility consequences.
03
Sport-related collapse
Continued high load during circulatory or metabolic compromise can provoke syncope, arrhythmia, worsening fracture and sudden medical deterioration.
04
Exclusion from care
Weight stigma, misgendering, inaccessible communication and culturally irrelevant plans reduce disclosure, attendance, nourishment and trust in services.
05
Iatrogenic reinforcement
Praise for loss, restrictive diet advice or premature return to exercise can validate disordered rules and prolong physiological suppression.
Monitoring and follow-up
Follow weight or growth trajectory and rate of change, but pair it with intake, behaviours, physical observations, endocrine symptoms, function and patient-defined goals.
For active people, track training load, rest, fatigue, illness, performance, injury, bone pain and return-to-sport criteria alongside nutrition restoration.
Ask men and boys directly about libido, sexual function, muscularity distress, supplements, anabolic-androgenic steroids and exercise rather than using menstruation as the endocrine screen.
Review whether names, pronouns, interpreters, sensory environment, written materials, appointment format and food plan remain accessible and respectful.
Revisit food affordability, housing, caring responsibilities, religious observance, discrimination and safeguarding because structural barriers change over time.
Audit referral acceptance and waiting times by sex, age, ethnicity and other locally monitored characteristics to identify service-level exclusion without stereotyping individuals.
Special situations
Athlete pulse needs context
Training can lower resting heart rate, but restriction, loss, syncope, hypothermia or poor perfusion makes reassurance from fitness unsafe.
Stable weight can underfuel
Metabolic adaptation may hold weight while bone, endocrine, immune and performance systems bear the cost of low energy availability.
Amenorrhoea is not universal
It excludes many patients and may be masked by hormones; assess endocrine health using relevant anatomy, development and symptoms.
Identity is not pathology
Gender, sexuality, ethnicity and religion shape experience and access but should not be named as the disorder's cause without individual evidence.
Adaptation preserves fidelity
Concrete language, sensory planning, interpreters and familiar foods can deliver core treatment more accurately, rather than dilute it.
Weight stigma causes harm
Praising loss or prescribing further restriction can reinforce illness, delay atypical-anorexia recognition and undermine trust in larger-bodied patients.
Common pitfalls
01
Screening only young thin women and interpreting every athletic or muscular appearance as evidence of health.
02
Using absence of amenorrhoea, a normal BMI or normal blood results to exclude an eating disorder or RED-S.
03
Equating RED-S with anorexia, or overlooking eating-disorder cognitions because underfueling began accidentally.
04
Returning an athlete to training because weight improved without assessing energy intake, endocrine recovery, bone injury and physiological stability.
05
Treating gender identity, religious practice, cultural food or autism as an eating disorder instead of asking about change, impairment and meaning.
06
Using a family member to interpret sensitive questions about purging, sexuality, coercion or abuse.
07
Recommending a costly culturally alien meal plan without assessing food access, preparation, disability and household context.
08
Praising rapid loss in a larger-bodied person before checking restriction, compensation, symptoms and medical risk.
Autistic and otherwise neurodivergent people may need sensory, predictability, interoception and communication adaptations, but these needs do not exclude concurrent anorexia, bulimia or binge-eating disorder.
Older adults may have new illness or recurrence alongside frailty, isolation, swallowing difficulty, medication effects or medical disease, requiring parallel differential diagnosis and timely specialist treatment.
Men and boys may describe pursuit of leanness or muscularity, rigid protein or supplement rules, bulking and cutting cycles, compensatory training or steroid use rather than fear of fatness.
Purging, insulin restriction, stimulant or laxative use and deliberate dehydration can produce lethal metabolic harm that a routine weight check will miss.
Food insecurity, coercive weight control, abuse, minority stress and unsafe housing may constrain eating or disclosure and require practical and safeguarding intervention alongside treatment.
Bone pain or focal tenderness in an underfuelled athlete requires exercise restriction and assessment for stress injury; training through symptoms can progress an incomplete fracture.
05
Bone and injury assessment
Why
Identify focal bone pain, fracture history and indications for imaging or bone-density evaluation.
Interpretation and limitations
Suspected stress injury needs prompt sports or musculoskeletal assessment and load restriction; DXA interpretation requires age, sex and body-size expertise.
Barriers become explicit treatment targets, with safeguarding action when control, abuse or exploitation is suspected.
1
Assess nutrition, training load, eating-disorder psychopathology, bone injury and medical stability with sports medicine, dietetic and eating-disorder expertise as needed.
2Remove or modify exercise when instability, severe energy deficiency or stress injury makes participation unsafe, and address team or coach pressures with consent and safeguarding awareness.
3Restore energy availability and define a graded return using clinical, nutritional and injury recovery, not weight alone or pressure from competition dates.
03Adapted treatmentRemove access barriers collaborativelyCulture, gender, neurodivergence, disability, age, language or poverty affects assessment or treatment delivery.+
1Ask the person what adaptations matter, arrange a professional interpreter or accessible communication and include affordable familiar foods in nutritional work.
2Coordinate relevant services while preserving confidentiality, including gender care, autism support, social care, endocrinology, older-person care or substance services.
3Measure the same core physical and behavioural outcomes while adapting pace, sensory exposure, format, supporter involvement and environment.
04Higher-weight lossRespond to trajectory and physiologyA person at normal or high BMI has rapid loss, marked restriction or starvation symptoms.+
1Plot the amount and rate of loss, quantify actual intake and compensation, and assess circulation, glucose, electrolytes, ECG indications and psychiatric risk.
2Stop congratulatory or weight-loss messaging, explain that malnutrition can occur at any size and refer to specialist care without a BMI gate.
3Plan nutritional restoration and refeeding monitoring from current physiology, prior intake and trajectory while preventing renewed weight-stigmatising restriction.