Eating Disorders

  1. During clinical encounters with children, adolescents, and young adults include an assessment of the risk of eating disorders, irrespective of the patient’s gender, as this may be the only opportunity.
  2. When caring for a patient with ongoing psychological distress or unexplained physical symptoms ask about body image and self-harm behaviours, including disordered eating.
  3. In a patient for whom concerns about eating behaviours have been identified take an appropriate history, including:
    • Eating patterns, relationship with food, body image, distress
    • Underlying mental health, alcohol, and substance use problems, including previous psychological trauma
    • Use of prescribed and over-the-counter medications, tobacco, caffeine, laxatives, and supplements
  4. In a patient with disordered eating behaviour(s):
    • Assess for physiological and metabolic complications
    • Determine if there is a need for hospitalization or immediate intervention
  5. When an eating disorder has been diagnosed:
    • Discuss the impact and potential consequences, regardless of the patient’s acceptance of the diagnosis
    • Engage the parents/caregivers/partners in treatment when appropriate and with consent
    • Collaborate with the patient and, when appropriate, family to develop a treatment plan, including an inter- and intra-professional referral when necessary
    • Use simple cognitive behavioural intervention first (i.e., do not automatically assume tertiary care is needed)
    • Periodically reassess behaviours and their impact on mood, anxiety, cognitive function, and relationships
  6. When assessing a patient presenting with a problem that has defied diagnosis (e.g., arrhythmias without cardiac disease, an electrolyte imbalance without drug use or renal impairment, amenorrhea without pregnancy) include “complication of an eating disorder” in the differential diagnosis.

General Overview

  • Anorexia Nervosa (AN)
    1. Restriction of energy intake relative to requirements, leading to a significantly low body weight (BMI<18.5 or <5th percentile in children, or rate of weight loss) in the context of age, sex, developmental trajectory, and physical health.
    2. Intense fear of gaining weight or of becoming fat, or persistent behavior that interferes with weight gain, even though at a significantly low weight.
    3. Disturbance in the way in which one’s body weight or shape is experienced, undue influence of body weight or shape on self-evaluation, or persistent lack of recognition of the seriousness of the current low body weight.
    • Subtypes
      • Restricting type: During the last 3 months, the individual has not engaged in recurrent episodes of binge eating or purging behavior (i.e., self-induced vomiting or the misuse of laxatives, diuretics, or enemas). This subtype describes presentations in which weight loss is accomplished primarily through dieting, fasting, and/or excessive exercise.
      • Binge-eating/purging type: During the last 3 months, the individual has engaged in recurrent episodes of binge eating or purging behavior (i.e., self-induced vomiting or the misuse of laxatives, diuretics, or enemas).
  • Bulimia Nervosa (BN)
    1. Recurrent episodes of binge eating, characterized by both of the following:
      • Eating, in a discrete period of time (e.g., within any 2-hour period), an amount of food that is definitely larger than what most individuals would eat in a similar period of time under similar circumstances.
      • A sense of lack of control over eating during the episode (e.g., a feeling that one cannot stop eating or control what or how much one is eating).
    2. Recurrent inappropriate compensatory behaviors in order to prevent weight gain, such as self-induced vomiting; misuse of laxatives, diuretics, or other medications; fasting; or excessive exercise.
    3. The binge eating and inappropriate compensatory behaviors both occur, on average, at least once a week for 3 months.
    4. Self-evaluation is unduly influenced by body shape and weight.
    5. The disturbance does not occur exclusively during episodes of anorexia nervosa.
  • Avoidant/Restrictive Food Intake Disorder (ARFID)
    1. An eating or feeding disturbance (e.g., apparent lack of interest in eating or food; avoidance based on the sensory characteristics of food; concern about aversive consequences of eating) as manifested by persistent failure to meet appropriate nutritional and/or energy needs associated with one (or more) of the following:
      • Significant weight loss (or failure to achieve expected weight gain or faltering growth in children).
      • Significant nutritional deficiency.
      • Dependence on enteral feeding or oral nutritional supplements.
      • Marked interference with psychosocial functioning.
    2. The disturbance is not better explained by lack of available food or by an associated culturally sanctioned practice.
    3. The eating disturbance does not occur exclusively during the course of anorexia nervosa or bulimia nervosa, and there is no evidence of a disturbance in the way in which one’s body weight or shape is experienced.
    4. The eating disturbance is not attributable to a concurrent medical condition or not better explained by another mental disorder. When the eating disturbance occurs in the context of another condition or disorder, the severity of the eating disturbance exceeds that routinely associated with the condition or disorder and warrants additional clinical attention.

Screening questions

    • Does your weight/body shape cause you stress?
    • Recent weight changes?
    • Dieted in the last year?
    • SCOFF
      • Do you make yourself Sick (induce vomiting) because you feel uncomfortably full?
      • Do you worry that you have lost Control over how much you eat?
      • Have you recently lost more than One stone (14 lb {6.4 kg}) in a three-month period?
      • Do you think you are too Fat, even though others say you are too thin?
      • Would you say that Food dominates your life?

Risk Factors

    • Early puberty
    • Poor or abnormal growth curves in children and adolescents
    • Low or high body mass index, or weight fluctuations
    • Weight concerns among normal weight individuals
    • Activities and occupations that emphasize body, shape, and weight (e.g. ballet, gymnastics, modeling)
    • Amenorrhea (primary or secondary)
    • Type 1 diabetes
    • Family history of ED


  • Rate/amount of weight loss
  • Dietary intake (quantity, restriction)
  • Compensatory behaviour (vomiting, laxatives, diuretics, exercise)
  • Attitudes about weight / Body image
  • Mood symptoms, suicidality
  • Menstrual history
  • Associated symptoms
    • Exertional or chronic fatigue, weakness, dizziness, pre/syncope, hot flashes, cold intolerance, depression
    • Cardio: Palpitations, CP, SOB, peripheral edema
    • Dental: Tooth pain (decay/cavities), mucosal bleeding/trauma and parotid gland enlargement
    • GI: Abdominal pain, early satiety, bloating, constipation
    • Endo: Amenorrhea, decreased libido, infertility
    • Derm: Hair loss, brittle nail and skin changes, poor healing
  • PMH (psych, trauma, DM1, growth history)
  • Medications (insulin, OCP, laxatives/diet pills, OTC)
  • Family history (eating disorder, psychiatric disorder)

Physical Exam

  • Vital Signs (eg. HR<60, BP<90/60, Temp<36)
    • Orthostatic vitals (supine, standing)
  • General Appearance
    • Height/Weight and BMI; weight in kilograms divided by height in meters squared
    • Hydration status
    • Enlargement of parotid or submandibular salivary glands in BN
    • Dental erosion due to frequent vomiting
  • Cardiac, r/o murmur
  • Skin
    • Brittle hair and fingernails
    • Lanugo hair
    • Dry skin
    • Pretibial edema
    • Russell sign (callous on MCP from teeth abrasion during self-induced emesis)
  • MSK
    • Muscle strength
    • Sit-up Squat Stand test (muscle weakness)


  • Determine level of medical acuity
    • EKG
      • Bradycardia, non-specific ST-T wave changes including ST segment depression, U waves in the presence of hypokalemia and hypomagnesemia
    • CBC (hemoglobin, leukocytes, platelets)
    • Serum electrolytes (Na, K, Glucose, Blood urea nitrogen, Creatinine, Calcium, Magnesium, Phosphate)
    • TSH, T4, T3
    • Liver function tests (AST, ALT, bilirubin)
      • Amylase/lipase
    • Albumin, transferrin
    • UA
    • BhCG r/o pregnancy
    • Consider celiac screen
  • If underweight > 6 months
    • Bone densitometry to assess for osteopenia and osteoporosis
    • Abdominal ultrasound to assess maturity of ovaries and uterus
    • FSH, LH, and estradiol levels in females
    • Testosterone levels in males


  • Medical stabilization
    • Assess outpatient vs. admission if needed for safety
  • Assess and treat coexisting psychiatric conditions (MDE, anxiety, substance use)
  • Nutritional rehabilitation with multidisciplinary approach
    • Family-based treatment
    • Individual Psychotherapy, FBT/CBT
    • Psychiatry
    • Dietician / nutritional rehab
    • School
    • Support groups / resources
  • Target weight range in AN (90% of expected weight)
    • Gradual weight gain in AN (1lb/week)
      • Limit exercise
  • Regular appointments with vitals, weight/BMI, and blood tests repeated
    • Complications (tooth decay, amenorrhea, electrolyte)
    • Disease activity (eating patterns, exercise, laxative)
  • Consider Pharmacology
    • SSRI / Fluoxetine at higher doses (60mg/d) in BN
    • Multivitamins with iron and Vitamin D
    • Consider Zinc 50mg PO daily (aids in weight gain)
    • Treat acne (as patient re-experience puberty as they gain weight)
  • Establish non-negotiable physical and nutritional indicators for hospitalization, eg.
    • Suicide risk, food refusal
    • Vitals unstable
      • Core temperature < 35.5°C or 95.5°F
      • Heart rate < 40 beats per minute or severe bradycardia
      • Blood pressure < 90/60 mm Hg or orthostatic hypotension
    • ECG arrhythmia
    • Electrolyte abnormalities
      • Sodium < 127 mmol/l
      • Potassium < 2.3 mmol/l
      • Hypoglycaemia; blood glucose < 2.5 mmol/l
      • Hypophosphataemia; phosphorous below normal on fasting
      • Magnesium < 0.6 mmol/l (normal above 0.7 mmol/l)
      • Rapid and progressive weight loss
    • Acute medical complications of malnutrition
      • Signs of inadequate cerebral perfusion (confusion, syncope, loss or decreased level of consciousness, organic brain syndrome, ophthalmoplegia, seizure, ataxia)
      • Seizure
      • Heart failure
      • Pancreatitis
      • Severe acrocyanosis
      • Dehydration that does not reverse within 48 hrs
      • Muscular weakness
    • Comorbid psychiatric or medical (poorly controlled diabetes type 1)
    • Pregnancy with an at risk foetus
    • Inadequate weight gain, failure of outpatient treatment

Motivational Interviewing

    • Establishing rapport:
      • Open-ended questions such as, “How have things been going with your eating?” or “Do you have concerns about your eating?” or “What is most important to you about your eating and health?”
    • Assessing Readiness:
      • “How do you feel about making changes to your eating?” or “How do you feel about making changes to improve your physical health?”
    • Provide Feedback:
      • “What is your reaction to these test results?” or “Would more information be helpful?”
    • Offer further support targeted to level of readiness for change:
      • For clients who are not “ready” to make change: “What would it take for you to consider thinking about change?”
      • For clients who are unsure about change: “What are the things you like and don’t like about your eating disorder?”
      • For clients who are ready to make change: “What would you like to work on changing?”

Refeeding syndrome

  • Metabolic changes during refeeding of a malnourished patient
  • Risk of hypophosphatemia leading to heart failure, arrhythmia, respiratory failure
    • Prevent with careful slow refeeding/monitoring and phosphate supplementation