Obesity in Adults—Clinician Algorithm

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Your patient’s BMI matters

The Canadian Task Force on Preventive Health Care (CTFPHC) recommends measuring height and weight and then calculating Body Mass Index (BMI) at appropriate primary care visits (strong recommendation, very low quality evidencei).

  • Recommendations apply to most adults ≥ 18 years of age
  • Recommendations do not apply to pregnant women or people with health conditions where weight loss is inappropriate
  • Recommendations do not apply to people with BMI ≥ 40, who will benefit from specialized bariatric programs

What is your patient’s BMI?

Calculate BMI by measuring height and weight and using BMI Chart.

BMI Classification Recommendation
BMI < 18.5 Underweight This category is outside the scope of this guideline.
18.5 ≤ BMI ≤ 24.9 Normal weight Do not offer formal, structured behavioural interventions aimed at preventing weight gain in adults (weak recommendation; very low-quality evidence).
25 ≤ BMI ≤ 29.9 Overweight Have a discussion with your patient, and offer or provide referral to structured behavioural interventions aimed at weight loss (weak recommendation; moderate-quality evidence).
30 ≤ BMI ≤ 39.9 Obese Have a discussion with your patient, and offer or provide referral to structured behavioural interventions aimed at weight loss (weak recommendation; moderate-quality evidence).
30 ≤ BMI ≤ 39.9 Obese and at high risk of diabetes.ii Offer or refer the patient to structured behavioural interventions aimed at weight loss (strong recommendation; moderate quality evidence).
BMI > 40  Severely obese This category is outside the scope of this guideline.

 

What are “appropriate primary care visits”?

  • Routine visits, visits for medication renewal, and other visits where the primary care practitioner deems it appropriate

What are “structured behavioural interventions”?

  • Programs focused on behaviour modification that involve several sessions over a period of weeks to months
  • Recommended programs should focus on:
    • Modifying diet
    • Increasing exercise
    • Making lifestyle changes
    • Any combination of these
  • Programs for obesity management may also include:
    • Counselling
    • Education or support
    • Environmental changes (e.g., use of a smaller plate)

Can I instruct my patients to calculate their own BMI? Or can I estimate it?

  • We recommend that physicians (or another member of the health care team) measure weight and height to calculate the patient’s BMI.
  • Adults tend to overestimate their own height and underestimate their own weight
  • Visual estimation by clinicians is often inaccurate and will not detect the relatively small gains occurring among most adults.

BMI Chart

95 lbs 100 lbs 105 lbs 110 lbs 115 lbs 120 lbs 125 lbs 130 lbs 135 lbs 140 lbs 145 lbs 150 lbs 155 lbs 160 lbs 165 lbs 170 lbs 175 lbs 180 lbs 185 lbs 190 lbs 195 lbs 200 lbs 205 lbs 210 lbs 215 lbs 220 lbs 225 lbs 230 lbs 235 lbs 240 lbs
43 kgs 45 kgs 47 kgs 50 kgs 52 kgs 54 kgs 56 kgs 59 kgs 61 kgs 63 kgs 65 kgs 68 kgs 70 kgs 72 kgs 75 kgs 77 kgs 79 kgs 81 kgs 84 kgs 86 kgs 88 kgs 90 kgs 93 kgs 95 kgs 97 kgs 99 kgs 102 kgs 104 kgs 106 kgs 109 kgs
5′0″ 152.5 cm 19 20 21 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47
5′1″ 155 cm 18 19 20 21 22 23 24 25 26 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 43 44 45
5′2″ 157.5 cm 17 18 19 20 21 22 23 24 25 26 27 27 28 29 30 31 32 33 34 35 36 37 37 38 39 40 41 42 43 44
5′3″ 160 cm 17 18 19 19 20 21 22 23 24 25 26 27 27 28 29 30 31 32 33 34 35 35 36 37 38 39 40 41 42 43
5′4″ 162.5 cm 16 17 18 19 20 21 21 22 23 24 25 26 27 27 28 29 30 31 32 33 33 34 35 36 37 38 39 39 40 41
5′5″ 165 cm 16 17 18 18 19 20 21 22 22 23 24 25 26 27 27 28 29 30 31 32 32 33 34 35 36 37 37 38 39 40
5′6″ 167.5 cm 15 16 17 18 19 19 20 21 22 23 23 24 25 26 27 27 28 29 30 31 31 32 33 34 35 36 36 37 38 39
5′7″ 170 cm 15 16 17 17 18 19 20 20 21 22 23 23 24 25 26 27 27 28 29 30 31 31 32 33 34 34 35 36 37 38
5′8″ 172.5 cm 14 15 16 17 17 18 19 20 21 21 22 23 24 24 25 26 27 27 28 29 30 30 31 32 33 33 34 35 36 36
5′9″ 175 cm 14 15 16 16 17 18 18 19 20 21 21 22 23 24 24 25 26 27 27 28 29 30 30 31 32 32 33 34 35 35
5′10″ 177.5 cm 14 14 16 16 16 17 18 19 19 20 21 22 22 23 24 24 25 26 27 27 28 29 29 30 31 32 32 33 34 34
5′11″ 180 cm 13 14 15 15 16 17 17 18 19 20 20 21 22 22 23 24 24 25 26 26 27 28 29 29 30 31 31 32 33 33
6′0″ 182.5 cm 13 14 14 15 16 16 17 18 18 19 20 20 21 22 22 23 24 24 25 26 26 27 28 28 29 30 31 31 32 33
6′1″ 185 cm 13 13 14 15 15 16 16 17 18 18 19 20 20 21 22 22 23 24 24 25 26 26 27 28 28 29 30 30 31 32
6′2″ 187.5 cm 12 13 13 14 15 15 16 17 17 18 19 19 20 21 21 22 22 23 24 24 25 26 26 27 28 28 29 30 30 31
6′3″ 190 cm 12 12 13 14 14 15 16 16 17 17 18 19 19 20 21 21 22 22 23 24 24 25 26 26 27 27 28 29 29 30
6′4″ 192.5 cm 12 12 13 13 14 15 15 16 16 17 18 18 19 19 20 21 21 22 23 23 24 24 25 26 26 27 27 28 29 29
  1. Find your height on the left side
  2. Find your weight on the top
  3. Your BMI number is where the two numbers meet

(For example—someone who is 5′9″ and 145 lbs has a BMI of 21)

  • Under healthy weight: BMI < 18.5
  • Healthy weight: BMI 18.5–24.9
  • Overweight: BMI 25–29.9
  • Obese: ≥ BMI 30

Footnotes

  1. For explanation of GRADE categories of recommendations and quality of evidence, please see our GRADE page.
  2. High-risk status is defined by 10-year risk of diabetes of ≥ 33%, which can be assessed using the CANRISK or FINDRISC risk assessment tools.