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.

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

Underweight^{Footnote 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 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.

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.

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

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.