1. In patients who appear to be obese, make the diagnosis of obesity using a clear definition (i.e., currently body mass index) and inform them of the diagnosis.
  2. In all obese patients, assess for treatable co-morbidities such as hypertension, diabetes, coronary artery disease, sleep apnea, and osteoarthritis, as these are more likely to be present.
  3. In patients diagnosed with obesity who have confirmed normal thyroid function, avoid repeated thyroid-stimulating hormone testing.
  4. In obese patients, inquire about the effect of obesity on the patient’s personal and social life to better understand its impact on the patient.
  5. In a patient diagnosed with obesity, establish the patient’s readiness to make changes necessary to lose weight, as advice will differ, and reassess this readiness periodically.
  6. Advise the obese patient seeking treatment that effective management will require appropriate diet, adequate exercise,and support (independent of any medical or surgical treatment), and facilitate the patient’s access to these as needed and as possible.
  7. As part of preventing childhood obesity, advise parents of healthy activity levels for their children.
  8. In managing childhood obesity, challenge parents to make appropriate family-wide changes in diet and exercise, and to avoid counterproductive interventions (e.g., berating or singling out the obese child).

General Overview

  • Adult BMI
    • ≥25 Overweight
    • ≥ 30 Obese class 1
    • ≥ 35 Obese class 2
    • ≥ 40 Obese class 3
  • Overestimated/underestimated depending on muscle:fat distribution
    • eg. South Asian criteria for BMI
      • ≥23 Overweight
      • ≥25 Obese
  • Measure waist circumference, particularly if BMI ≤35 to track progress (no clear evidence for cutpoints)
  • Co-morbidities
    • Hypertension, diabetes, coronary artery disease, sleep apnea, osteoarthritis
  • Secondary causes
    • Endocrine (hypothyroidism, Cushing's, PCOS)
    • Medications (insulin, sulfonylureas, antipsychotics)


  • History and physical exam rule out secondary causes (Endocrine, OSA)
    • Vitals (Blood pressure)
    • Weight, height, waist circumference
    • Impact personal and social life
    • Rule out depression, eating disorder
  • Labs
    • HbA1c or fasting blood glucose
    • Lipid profile
    • Consider Thyroid (avoid repeating if confirmed normal)


  • Readiness to change
  • Support
  • Multidisciplinary approach
    • Dietician
    • Personal Trainer
    • Psychology/Psychiatry (Cognitive behavioural therapy)
    • Obesity specialist/Endocrinologist
  • Lifestyle
    • Diet
      • May consider a weight los diet (reduction in dietary energy)
        • High protein - Low fat diet
    • Exercise
      • 30 minutes daily of moderate intensity, increase to 60 minutes daily
  • BMI ≥30 (Obesity class 2-3) after lifestyle/behavioural changes have failed
    • Structured behavioural interventions (weight loss program)
    • Pharmacotherapy (not recommended by Canadian Taskforce)
      • Orlistat 120mg PO daily-TID
        • Stop medication if weight loss <5% at 3 months
        • No effect on mortality
        • Adverse effects: Bloating, steatorrhea, fecal incontinence
          • Lack of longterm safety data
          • Supplement with multivitamin 2h before or after medication
      • Consider GLP-1/SGLT2 for weight loss in diabetes (in addition to Metformin)
    • BMI ≥ 40 or ≥ 35 with comorbidity (OA, OSA), consider Bariatric Surgery
      • Weight loss
      • Reduce prevalence of chronic disease (eg. DM, HTN, DLP, MSK pain - RR decrease by 25%)


    • Normal - BMI < 85th percentile
    • Overweight- BMI > 85th percentile
    • Obese > 97th percentile
      • Severe Obesity >99th percentile


    • Structured behavioural interventions
    • Family-wide changes in diet and activity (family-oriented behaviour therapy)
      • Avoid counterproductive interventions (e.g., berating or singling out the obese child)
      • Encourage positive reinforcement
    • Diet
      • Family meals
      • Healthy snacking
      • Decreased sugar consumption (juices, drinks)
      • Decrease portion size
      • Increase vegetables
    • Activity (WHO recommends 60 minutes moderate-vigorous daily)
      • Focus on fun/recreational activity
      • Limit screen time
      • Limit motorized transport
      • Limit time spent indoors
      • Limit sitting (eg. stroller)
    • Sleep