Body Mass Index (BMI) is a common tool in Canada for estimating healthy body weight and assessing the risks associated with being overweight or underweight. The latest from the Canadian Community Health Survey shows that nearly 1 out of 3 Canadian adults is obese based on their BMI.
Being overweight or obese increases the risk of getting stuff like heart disease, diabetes, cancer, and other chronic illnesses by a lot. These illnesses can reduce quality of life and drive up healthcare costs. The good news is that keeping a healthy BMI by improving lifestyle habits can help lower these risks.
This article provides a look at BMI in Canada, including current trends, its limitations, and actionable strategies for improving your health.
What Is the Body Mass Index (BMI)?
Body Mass Index (BMI) is a common measurement tool used to assess weight status and associated health risks in adults aged 20 and older. BMI provides a reliable indicator of body fat for most people.
More specifically, it is a mathematical formula calculated as follows:
BMI = Weight (kg) / Height (m)2
For example, an individual weighing 70 kg (154 lbs) and measuring 1.75 meters (5 ft 9 in) in height would have a BMI of 22.9, which falls within the normal range.
While BMI correlates with body fat percentage in most adults, it does not directly quantify body fat. BMI is a screening tool that produces a single number meant to give a general indication of whether a person’s body weight is low, normal, or high relative to their height. It provides a benchmark for comparing weight status within populations.
BMI Classification for Canadians
Health Canada, aligning with the World Health Organization (WHO), uses the following standard BMI classifications for adults aged 18 and over
| BMI Classification | BMI Range (kg/m2) |
|---|---|
| Underweight | < 18.5 |
| Normal Weight | 18.5 – 24.9 |
| Overweight | 25.0 – 29.9 |
| Obese Class I | 30.0 – 34.9 |
| Obese Class II | 35.0 – 39.9 |
| Obese Class III | >= 40.0 |
The obesity range can be further subdivided into Class I (BMI 30-34.9), Class II (BMI 35-39.9) and Class III (BMI 40+) obesity, with increasing health risks at higher levels. Individuals classified as overweight or obese based on their BMI have an elevated risk for developing chronic conditions like heart disease, diabetes, cancer, and osteoarthritis, among others.
Those with a BMI below 18.5 may have nutritional deficiencies, osteoporosis, and also face health risks.
Source: Health Canada. Canadian Guidelines for Body Weight Classification in Adults
For children and adolescents (ages 2-17), BMI is interpreted using age- and sex-specific percentile charts from the WHO.
- Underweight: Below 5th percentile
- Healthy Weight: 5th to 85th percentile
- Overweight: 85th to 95th percentile
- Obese: Above 95th percentile
These pediatric charts account for the dynamic changes in height, growth rate, and body composition throughout childhood and puberty. BMI screening and growth monitoring in youth can identify early weight management issues and reduce long-term health risks.
Canada’s Overweight and Obesity Trends Based on BMI
Obesity rates in Canada have risen significantly over the past two decades, from 21% in 2003 to 30% in 2022 (latest data from Statistics Canada). Rates vary notably across Canada’s provinces and territories.
| Province | % Obese (alduts) | Compared to National Average (30%) |
|---|---|---|
| British Columbia | 26% | Lower |
| Alberta | 31% | About average |
| Saskatchewan | 38% | Higher |
| Manitoba | 34% | Higher |
| Ontario | 30% | Average |
| Quebec | 29% | Lower |
| New Brunswick | 43% | Higher |
| Newfoundland and Labrador | 42% | Higher |
| Prince Edward Island | 36% | Higher |
| Nova Scotia | 36% | Higher |
As shown, obesity rates were lowest in British Columbia at 26% and highest in New Brunswick at 43%. The prairie and Atlantic provinces generally had higher obesity prevalence compared to the national average of 30%.
The obesity rates in Canada are also segmented by age group and gender. The table below shows the obesity rate by gender and age group (2021)
| Age group | Both genders (%) | Males (%) | Females (%) |
|---|---|---|---|
| 18-34 | 22.5 | 22.3 | 22.7 |
| 35-49 | 32.9 | 33.8 | 31.9 |
| 50-64 | 33.7 | 36.4 | 31.1 |
| 65-79 | 31.5 | 30.9 | 32 |
| 80 or older | 21.2 | 19.6 | 22.4 |
| Total (age 18+) | 29.5 | 30.1 | 28.9 |
How Does Canada’s Average BMI Compare Internationally?
The rise in obesity has impacted countries globally, but BMI levels vary significantly by nation. The table below shows the mean BMI values for selected countries:
| Country | Mean BMI |
| Nauru | 32.5 |
| Tonga | 31.9 |
| Samoa | 31.7 |
| Kuwait | 30.0 |
| Qatar | 29.2 |
| United States | 28.8 |
| Mexico | 28.1 |
| New Zealand | 27.9 |
| Canada | 27.2 |
| Australia | 27.2 |
| Japan | 22.6 |
The highest BMIs were seen in Pacific islands like Nauru, while Japan maintained a lower BMI. The U.S. and Mexico had a high mean of over 28 among industrialized nations. Canada was above the OECD average of 26.6. Higher mean BMIs indicate greater obesity prevalence over time.
Monitoring BMI globally allows for the identification of high-risk regions and the sharing of best practices. Canada and other countries should act to improve nutrition and physical activity.
What Are the Limitations of BMI as a Health Indicator?
Despite being the most widely adopted proxy measure for indicating body fat and weight categories, BMI does have limitations:
- Does not differentiate between body fat, muscle, bone density, etc. Athletes may have higher BMIs due to increased muscle mass.
- Does not consider fat distribution (abdominal vs peripheral). Abdominal fat increases health risks.
- Less accurate for individuals at weight extremes or with certain medical conditions.
- Does not account for age, gender and ethnic differences in body composition.
- Not adjustable for proportionally shorter or taller individuals.
Due to these constraints, BMI should not be solely relied upon as a diagnostic tool. Rather, it is best utilized as part of a comprehensive health screening, alongside other metrics such as Waist Circumference (WC), Waist-to-Hip Ratio (WHR), cholesterol levels, and blood pressure, to evaluate weight-related health risks.
What Are the Health Risks of High and Low BMI?
Excess weight classified by a BMI in the overweight or obese ranges places individuals at heightened risk for developing an array of chronic health conditions, disabilities, and psychosocial issues:
- Cardiovascular diseases: Hypertension, coronary artery disease, congestive heart failure, stroke
- Metabolic disorders: Type 2 diabetes, dyslipidemia, fatty liver disease
- Respiratory problems: Obstructive sleep apnea, asthma, pulmonary embolism
- Musculoskeletal diseases: Osteoarthritis, back and joint pain, decreased mobility
- Mental illnesses: Depression, anxiety, eating disorders, and low self-esteem
- Cancers: Breast, uterine, colon, kidney, esophageal
- Increased mortality risk: Up to 9 years reduction in life expectancy
This wide range of detrimental health consequences shows the pressing need to address Canada’s high and climbing overweight and obesity rates, as revealed through BMI screening data. Canadians with a high BMI seeking life insurance may face challenges in finding affordable premiums and coverage.
While overweight and obesity are far more prevalent in Canada, a low BMI below 18.5 also poses health concerns of its own.
Underweight individuals may suffer from:
- Malnutrition: Insufficient energy and nutrient intake can arise from poverty, eating disorders, chronic diseases, substance abuse, or mental illness.
- Anemia: Underweight BMI can signify deficiencies in iron, folate, vitamin B12, or other nutrients vital for red blood cell production.
- Osteoporosis: Too little mechanical loading on bones over long periods can precipitate accelerated bone loss and fractures.
- Reproductive issues: Underweight women may experience irregular menstruation, infertility, or complications during pregnancy.
- Weakened immunity: Malnutrition hampers immune defences, raising risks for frequent or severe infections.
Therefore, an underweight BMI can be a vital red flag for underlying medical causes requiring further evaluation and care. It may also necessitate interventions to improve diet, nutrient status, and self-care behaviours in some patients.
What Strategies and Policies Address High BMI in Canada?
To counteract Canada’s high and rising BMI statistics, various initiatives have been undertaken by government agencies and public health groups:
- National public health campaigns promote healthy weights through engaging fitness tips and nutrition education.
- Provinces like Ontario, Alberta, and Nova Scotia have expanded access to no-cost or low-cost bariatric care, behavioural weight loss programs, and specialized obesity management clinics that are covered under provincial health plans.
- Proposed federal bills like C-211 aim to impose restrictions on marketing unhealthy foods and beverages to children in order to curb childhood obesity rates.
- Electronic medical records increasingly integrate BMI documentation prompts to standardize obesity screening and monitoring across providers.
- Federal grants fund research on emerging weight management solutions and subsidize programs targeting groups with high BMIs.
Recommendations for BMI Screening in Canada
Canadian clinical practice guidelines provide the following evidence-based recommendations for BMI screening and interpretation in order to guide obesity prevention efforts:
- All adults aged 18 years and older should have their BMI assessed at least once annually, with increased frequency for those who are overweight or obese.
- BMI should be interpreted in conjunction with age, gender, ethnicity, and muscle mass, not in isolation.
- For children/youth, BMI should be plotted on CDC BMI-for-age growth charts starting at age 2 years at each pediatric well-child visit.
- BMI screening should occur alongside other health assessments like waist circumference, blood pressure, and cholesterol.
- BMI results should inform individually tailored nutrition, exercise, and lifestyle recommendations to promote healthy weights.
While some limitations exist, routine, standardized BMI screening remains a crucial tool for tracking population health and facilitating timely interventions.
How Can Canadians Improve Their Body Mass Index?
If your BMI is in the underweight or overweight ranges, you can aim to reach a healthier weight through lifestyle adjustments:
- Consult your doctor for individualized weight loss or weight gain advice
- Fill half your plate with vegetables and fruits. These are rich in vitamins, minerals, and fibre
- Choose plant-based proteins like beans, lentils, and tofu more often. Include lean meats, fish, and low-fat dairy.
- Make at least half of your grain products whole grain, such as quinoa, brown rice, oats, and whole-wheat bread.
- Limit highly processed foods, as they are often high in sodium, sugar, and saturated fat.
- Gain weight healthfully if underweight by adding nutritious, high-protein and high-calorie foods to your diet under medical guidance.
- Increase physical activity to 30-45 minutes per day to expend excess calories if overweight or obese.
- Set realistic weight loss targets up to 2 lbs per week if overweight or 1 lb weekly if obese. More rapid loss may signal muscle wasting.
- Prioritize sleep and stress management. Chronic stress and insufficient sleep can contribute to weight gain and obesity. Aim for 7-9 hours of quality sleep per night and incorporate stress-reducing practices like mindfulness, meditation, or hobbies.
With time, consistency, and support from your healthcare team, reaching and sustaining a BMI in the normal range is an attainable goal that can optimize your health. Monitor your BMI over time to assess your progress.
Aside from BMI, other common stats like average IQ, average height and weight for men, average height and weight for women, and average life expectancy also offer insights into overall health, and these factors can sometimes play a role in life insurance assessments in Canada.
The bottom line
Your BMI is a single data point, not a complete definition of your health or self-worth. Focus on feeling your best through balanced nutrition, regular activity, and positive lifestyle habits aligned with Canada’s Food Guide and physical activity recommendations.
Stay motivated by monitoring your BMI over time and celebrating healthy improvements. Remember to be kind to yourself throughout the process. If you have concerns about your weight or BMI, reach out to your Canadian healthcare providers for personalized guidance.
By taking consistent, positive steps, you can work towards a healthier life, regardless of what the scale says.
FAQs related to Body Mass Index in Canada
How is BMI calculated in Canada?
BMI is calculated the same way in Canada as other countries: by dividing a person’s weight in kilograms by their height in meters squared.
What is considered a healthy BMI range in Canada?
In Canada, a BMI between 18.5 and 24.9 is considered healthy for most adults. Those with a BMI of 25-29.9 are considered overweight, while a BMI over 30 indicates obesity.
Where can Canadians find their BMI on medical reports?
Canadians can find their BMI listed on medical reports and lab results under the "Vitals" section, along with their height, weight, and other metrics.
Why do doctors in Canada use BMI to assess health?
BMI is an easy, inexpensive way for Canadian doctors to broadly assess body fat and predict obesity-related health risks like diabetes and heart disease. It is commonly used for population statistics.
Do all doctors in Canada use the same BMI scale?
Yes, all doctors and health professionals in Canada use the standard BMI scale as outlined by Health Canada and the World Health Organization guidelines.
Can BMI be inaccurate for certain groups in Canada?
Yes, BMI can be less accurate for very muscular Canadians, seniors who have lost muscle mass, and some ethnic groups. Doctors may interpret BMI differently for certain individuals.
Article Sources
- Health Canada. Healthy eating recommendations – Canada’s Food Guide. https://food-guide.canada.ca/en/healthy-eating-recommendations/
