Anorexia vs. Bulimia: A Clinical Guide to Spotting the Differences

When in doubt: Use the SCOFF questionnaire as a screening tool and refer to a specialist for full evaluation.

Let’s stay alert to the silent signs — and give these patients the compassionate care they need.

SCOFF stands for 5 key questions:

1. S – Do you make yourself Sick because you feel uncomfortably full?

2. C – Do you worry you have lost Control over how much you eat?

3. O – Have you recently lost more than One stone (≈6.35 kg) in a 3-month period?

4. F – Do you believe yourself to be Fat when others say you are too thin?

5. F – Would you say that Food dominates your life?

📝 Scoring:

• 1 point for each “yes”

• A score of ≥2 suggests a likely eating disorder and the need for further assessment.

Eating disorders can present subtly in clinical settings, especially in adolescents and young adults. Two of the most commonly encountered disorders—Anorexia Nervosa and Bulimia Nervosa—may share overlapping traits, yet they require distinct management strategies. Early identification can be lifesaving.

This blog post helps you, as a clinician, differentiate between anorexia and bulimia using characteristic signs and focused questioning during consultation.

Anorexia Nervosa (AN)

Main Feature:

• Persistent restriction of food intake due to an intense fear of weight gain or becoming fat, despite being significantly underweight.

Key Signs:

• Very low body weight (BMI often <17.5)

• Distorted body image – patients often see themselves as overweight even when emaciated

• Extreme control over eating – skipping meals, rigid calorie counting

• Excessive exercise aimed at weight loss

• Amenorrhoea (loss of menstrual periods in females)

• Medical complications like bone loss, bradycardia, electrolyte imbalances, and organ dysfunction

Bulimia Nervosa (BN)

Main Feature:

• Recurrent episodes of binge eating, followed by compensatory behaviors like self-induced vomiting, laxative use, or over-exercising to prevent weight gain.

Key Signs:

• Normal or slightly low weight (unlike anorexia)

• Loss of control during binge episodes

• Feelings of guilt or shame after eating

• Physical signs of purging: swollen cheeks, dental enamel erosion, calluses on knuckles (Russell’s sign), sore throat

• Electrolyte imbalances, especially hypokalemia

Key Difference in a Nutshell:

• Anorexia = restriction + underweight

• Bulimia = binge + purge, usually normal weight
  

🔍 Clinical Questions to Differentiate Anorexia from Bulimia

When a patient presents with concerns about eating, weight, or body image, asking the right questions can reveal the underlying diagnosis. Here's a table of targeted clinical questions, why they matter, and what they typically indicate:

Question	Why It’s Important	Suggests More Likely
Do you avoid eating or restrict how much you eat?	Reveals restrictive behavior	Anorexia
Have you lost a lot of weight recently?	Underweight status is a red flag	Anorexia
Do you ever eat large amounts of food in a short time (binges)?	Identifies binge episodes	Bulimia (also in binge-purge type anorexia)
After eating, do you make yourself vomit or use laxatives?	Detects purging behavior	Bulimia (can occur in anorexia too)
Do you feel out of control while eating?	Loss of control = hallmark of bingeing	Bulimia
Do you believe you're overweight even when others say you're underweight?	Distorted body image	Anorexia
Do you exercise excessively to control your weight?	May be present in both, but more extreme in anorexia	Both, more so anorexia
Has your period stopped (if female)?	Common in anorexia due to malnutrition	Anorexia
How would you describe your current weight?	Helps assess nutritional status	Anorexia = underweight; Bulimia = normal weight

🩺 Clinical Takeaway

• Anorexia Nervosa typically involves restriction and low body weight.

• Bulimia Nervosa involves bingeing and purging, often in the context of normal weight.

• Both are serious, potentially life-threatening disorders that benefit from early recognition and multidisciplinary management involving medical, nutritional, and psychological support.