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Food and Nutrition

Canadian Guidelines for Body Weight Classification in Adults - Quick Reference Tool for Professionals

Cat. No: H49-179/2003-1E
ISBN 0-662-33496-5

Highlights

  • The Canadian Guidelines for Body Weight Classification in Adults uses the body mass index and waist circumference as indicators of health risk.
  • This classification system is aligned with the World Health Organization's (WHO) recommendations widely adopted internationally.
  • This classification system is derived from population data. When used with individuals, weight classification is only one component of a more comprehensive health assessment needed to clarify health risk.
  • The classification system is not intended for use with:
    • those under 18 years of age, and
    • pregnant and lactating women.

Special consideration is also needed when using the classification system. It may underestimate or overestimate health risks in specific groups such as: young adults who have not reached full growth, adults who naturally have a very lean body build, highly muscular adults, adults over 65 years of age, and certain ethnic and racial groups.

Body Mass Index (BMI)

The BMI (weight (kg)/height(m)²) is not a direct measure of body fat but it is the most widely investigated and most useful indicator, to date, of health risk associated with under and overweight.

Health Risk Classification According to Body Mass Index (BMI).
Classification BMI Category (kg/m²) Risk of developing health problems

Note: For persons 65 years and older the 'normal' range may begin slightly above BMI 18.5 and extend into the 'overweight' range.

Adapted from: WHO (2000) Obesity: Preventing and Managing the Global Epidemic: Report of a WHO Consultation on Obesity.

Underweight <18.5 Increased
Normal Weight 18.5 - 24.9 Least
Overweight 25.0 - 29.9 Increased
Obese Class I 30.0 - 34.9 High
Obese Class II 35.0 - 39.9 Very high
Obese Class III >=40.0 Extremely high

Some health problems associated with body weight

Overweight and obesity

  • Type 2 diabetes
  • Dyslipidemia
  • Hypertension
  • Coronary heart disease
  • Gallbladder disease
  • Obstructive sleep apnea
  • Certain cancers

UnderweightFootnote 1

  • Undernutrition
  • Osteoporosis
  • Infertility
  • Impaired
  • immunocompetence

Waist Circumference (WC)

  • WC is an indicator of health risk associated with excess abdominal fat.

To determine WC, the measurer should stand beside the individual. WC is measured at the part of the torso located midway between the lowest rib and the iliac crest (top of pelvic bone). The tape should fit without compressing any underlying soft tissues.

Health Risk Classification According to Waist Circumference (WC)
WC Cut-off Points Risk of developing health problemsTable 2 footnote 1

Table 2 footnotes

Table 2 footnote 1

Risk for type 2 diabetes, coronary heart disease, hypertension

Return to table 2 footnote 1 referrer

Adapted from: WHO (2000) Obesity: Preventing and Managing the Global Epidemic: Report of a WHO Consultation on Obesity.

Men >=102 cm (40 in.) Increased
Women >= 88 cm (35 in.)

Health risk classification using both BMI and WC

  • WC measurement can be used for individuals with a BMI in the 18.5-34.9 range. For BMIs >= 35.0, WC measurement does not provide additional information regarding level of risk.
Health risk classification according to Body Mass Index (BMI) and Waist Circumference (WC)
WC BMI
Normal Overweight Obese Class I

Adapted from: National Institutes of Health (1998) Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults: The Evidence Report.

<102 cm (Males Least risk Increased risk High risk
<88 cm (Females)
>=102 cm (Males) Increased risk High risk Very high risk
>=88 cm (Females

Body Mass Index (BMI) Nomogram

Body Mass Index Nomogram

For a quick determination of BMI (kg/m2), use a straightedge to help locate the point on the chart where height (in or cm) and weight (lb or kg) intersect. Read the number on the dashed line closest to this point. For example, an individual who weighs 69 kg and is 173 cm tall has a BMI of approximately 23.

Example of an individual who weighs 69 kg and is 173 cm tall has a BMI of approximately 23

Refer to the table below to identify the level of health risk associated with a particular BMI.

BMI Formula

BMI can also be calculated using this formula

BMI = weight (kg)/height(m)²

Note: 1 inch = 2.54 centimetres and 1 pound = 0.45 kilograms

Health Risk Classification According to Body Mass Index (BMI)
BMI Risk of developing health problems

Note: For persons 65 years and older the 'normal' range may begin slightly above BMI 18.5 and extend into the 'overweight' range.

Adapted from: WHO (2000) Obesity: Preventing and Managing the Global Epidemic: Report of a WHO Consultation on Obesity.

< 18.5 Increased
18.5 - 24.9 Least
25.0 - 29.9 Increased
30.0 - 34.9 High
35.0 - 39.9 Very high
>= 40.0 Extremely high

To clarify risk for each individual, other factors such as lifestyle habits, fitness level, and presence or absence of other health risk conditions also need to be considered.

Footnotes

Footnote 1

May indicate an eating disorder or other underlying illness.

Return to footnote 1 referrer