The Core Paradigm: Obesity as a Disease
“Obesity is a complex chronic disease in which abnormal or excess body fat (adiposity) impairs health, increases the risk of long-term medical complications, and reduces lifespan.”
Recognition: Healthcare providers should treat obesity as a chronic disease rather than a simple lifestyle choice.
Etiology: Its causes are complex, involving genetics, socio-economic status, and environmental factors that extend far beyond “calories in vs. calories out.”
Weight Bias: Stigma and discrimination are pervasive in healthcare and significantly impact patient wellbeing and treatment outcomes.
Statistical Snapshot: Canada (1985–2016)
The prevalence of obesity in Canada has risen dramatically over the last three decades.
The Three-Fold Increase: Since 1985, the prevalence of adult obesity has tripled.
Current Impact: As of 2016, obesity affects approximately 26.4% (8.3 million) of Canadian adults.
The Overweight Gap: An additional 34% of adults (10.6 million) are classified as overweight.
The Severe Surge: Severe obesity () is the fastest-growing subgroup, increasing by 455% since 1985.
Economic Burden: In 2010, the total cost of obesity to the Canadian economy was estimated at $7.1 billion.
Clinical Classifications & Assessment
1. Body Mass Index (BMI)
BMI is calculated as weight () divided by height squared ().
| Classification | BMI Range (kg/m2) | Health Risk |
| Overweight | 25.0 – 29.9 | Increased |
| Obesity Class I | 30.0 – 34.9 | High |
| Obesity Class II | 35.0 – 39.9 | Very High |
| Obesity Class III | ≥ 40.0 | Extremely High |
Clinical Pearl: BMI should not be used in isolation; it must be paired with other clinical assessment tools.
2. Abdominal Obesity (Waist Circumference)
Abdominal adiposity is often a more significant predictor of health risk than BMI alone.
Men: Increased risk at (40 inches).
Women: Increased risk at (35 inches).
Trend: Average waist circumference has increased by 6.5 cm for men and 10.6 cm for women over recent decades.
3. Edmonton Obesity Staging System (EOSS)
A five-point system (0–4) that assesses comorbidity and functional status.
It is a better predictor of mortality than BMI or waist circumference alone.
Complications & Impact
Obesity is a major driver of premature morbidity and mortality in Canada.
Life Expectancy: Obesity can reduce lifespan by 6 to 14 years.
Chronic Disease: Increases risk for Type 2 diabetes, heart disease, stroke, and non-alcoholic fatty liver disease.
Cancer: Approximately 20% of all cancers are attributed to obesity.
Mental Health: Individuals with obesity are twice as likely to be diagnosed with a mood disorder.
Quality of Life: Reduced mobility, chronic pain (osteoarthritis), and mental health strain significantly lower health-related quality of life.