Obesity is a complex chronic disease in which abnormal or excess body fat impairs health, increases the risk of long-term medical complications and reduces lifespan. Because it is a chronic disease, obesity often requires lifelong interventions to maintain health status (just like other chronic diseases such as diabetes and heart disease).
Put simply, you have obesity if (and only if) your weight affects your health.
Research tells us obesity is caused by a complicated interaction of a large number of genetic, metabolic (the way your body breaks down food and transforms it into energy), behavioural and environmental factors. Importantly, this means that obesity does not arise simply from poor choices, overeating or a lack of physical activity, yet this unscientific and biased point of view remains common in society. Read more about weight bias, stigma and discrimination below.
Watch the video at the top of this page and check out the infographic below to learn more about how the brain and your genetics affect your weight.
Further reading: The Science of Obesity (from the 2020 Canadian Adult Obesity Clinical Practice Guidelines)
To guide you and your clinician on selecting the obesity care options that are right for you, a clinical evaluation is needed to determine how your weight impacts your health and well-being. This may include both a mental health assessment and a physical exam, which may include various tests (e.g., blood pressure, blood tests). Remember, weight bias and stigma are common in healthcare and can be detrimental to helping you achieve your health goals. Healthcare providers should conduct their obesity assessment in a sensitive and non-judgmental way, as they would for any other chronic disease.
Note: Historically, body mass index (BMI; calculated as your weight in kilograms divided buy your height in metres squared) has been widely used to estimate body fat in individuals and in population health research. However, while BMI can still play a role in screening for obesity, it does not provide an objective assessment of health status, and so other investigations are necessary for an accurate diagnosis and tailored treatment plan.
Further reading: Assessment of People Living with Obesity (from the 2020 Canadian Adult Obesity Clinical Practice Guidelines)
Adults living with obesity should receive individualized care plans that address their root causes of obesity and that provide support for behavioural change (e.g., nutrition, physical activity) and additional therapies, which may include psychological, pharmacologic (medications) and surgical interventions (bariatric surgery).
Weight loss achieved with health behavioural changes is usually 3%–5% of body weight, which can result in meaningful improvement in obesity-related complications. The amount of weight loss varies substantially among individuals, depending on biological and psychosocial factors and not simply on individual effort. Further reading: Effective Psychological and Behavioural Interventions in Obesity Management, Physical Activity in Obesity Management and Medical Nutrition Therapy in Obesity Management (all from the 2020 Canadian Adult Obesity Clinical Practice Guidelines).
Medications may compliment the magnitude of weight loss/stability behavioural changes can achieve alone, and they can help prevent weight regain. Currently, there are three medications approved for obesity treatment in Canada, with a fourth expected in 2022. Your doctor can help you decide if medication, and which medication, is right for you. Further reading: Pharmacotherapy in Obesity Management (from the 2020 Canadian Adult Obesity Clinical Practice Guidelines).
Bariatric surgery may be helpful for people over the age of 18 with a BMI of 35 kg/m² with one at least additional obesity-related complication such as type 2 diabetes, hypertension, hyperlipidemia (high cholesterol), coronary artery disease, severe reflux, obstructive sleep apnea and others. Bariatric surgery is also indicated for individuals with a BMI of 40 kg/m² without the presence of obesity-related complications, and there may be a benefit in people with a BMI between 30 and 34.9 kg/m² who have not responded to non-surgical attempts at weight loss with obesity-related complications, especially T2DM. The 2020 Canadian Adult Obesity Clinical Practice Guidelines have three chapters dedicated to bariatric surgery.
Note: Obesity Canada’s research indicates that access to multidisciplinary care, behavioural supports, medications (public or private coverage) and bariatric surgery vary wildly. In 2019, less than 20% of the Canadian population with private drug benefit plans had access to the three medications indicated and approved by Health Canada for obesity treatment. Every province and territory received a grade of ‘F’ for public coverage of obesity medications; the federal government received a ‘C’. All provinces that offer bariatric surgery except Quebec received an ‘F’ for overall access to surgery, as did Canada as a whole. Quebec receives a ‘D’. Further reading: Report Card on Access to Obesity Treatments for Adults in Canada 2019.
Not all commercial weight loss programs and products are created equal. While short-term “quick-fix” solutions can sound appealing, they are usually temporary and are therefore linked to high rates of weight regain. Few commercial approaches have any quality scientific evidence to back up their claims, and some may even be dangerous. Further reading: Commercial Products and Programs in Obesity Management (from the 2020 Canadian Adult Obesity Clinical Practice Guidelines).
Weight management is never about how much weight you can lose or how fast you can lose it – all that matters for your overall health, well-being and quality of life is how much weight you can keep off while still living a life that you can enjoy. This is called your “best weight.”
Obesity is a medical condition that can be caused by multiple factors. However, people often think that individuals living with obesity are personally responsible for their weight because they just eat too much or do not exercise enough. This belief is a fundamental driver of weight bias, stigma and discrimination. Weight discrimination can affect individual’s access to education, employment and medical care, causing health and social inequalities. Stigma and weight discrimination is an added burden to individuals’s health and can be a barrier to weight management. This is why fighting weight bias is a core objective for Obesity Canada.
Further reading: Reducing Weight Bias in Obesity Management, Practice and Policy (from the 2020 Canadian Adult Obesity Clinical Practice Guidelines).
Visit our weight bias page for more information and resources.
Obesity rose dramatically in Canada and in many other countries over the last 30 years and is a global public health priority. Obesity is estimated to affect 13% of the adult population worldwide, affecting over 650 million individuals. Globally, obesity is one of the largest contributors to poor health, with annual costs estimated to be USD $2 trillion dollars, equivalent to 2.8% of the world’s GDP and equal to the costs of smoking. In Canada, annual direct medical care costs for hospital admissions, medication use, physician fees and emergency room visits were estimated to be CAD $3.9 billion in 2010. When indirect costs are included, such as short- and long-term disability, absenteeism, presenteeism and premature death, this increases to $7.1 billion.
In Canada, the prevalence of obesity in adults (18 years +) increased dramatically over the last three decades independent of whether actual or self-report= measures are examined. Using actual measures of heights and weights, obesity, defined using BMI, increased more than 300% from 6.1% in 1985 to 26.4% in 2015/2016. When using self-report measures, the prevalence was 20.1% equating to just over a 200% increase.
The prevalence of obesity varies by geographical region. In 2015–2016, the prevalence of obesity was highest among the Atlantic Provinces (Newfoundland and Labrador, Prince Edward Island, Nova Scotia and New Brunswick) and lowest in British Columbia and Quebec. Since 1985, the proportion of people affected by severe obesity increased disproportionately. Between 1985 and 2016, Class II and III obesity increased by 455% (from 1.1% to 6.0%) affecting an estimated 1.9 million adults. This increase in prevalence is a major concern as severe obesity (Class II and III) is associated with a much higher risk of ill health and premature mortality than Class I obesity. Although the prevalence of obesity (BMI ≥ 30 kg/m2) has continued to increase over the last 10 years, data suggest the prevalence of obesity has remained largely stable between 2007 and 2017.
Increasing abdominal obesity is associated with significant health risks. In Canada, over the last three decades, abdominal obesity measured by waist circumference presents a concerning picture. Using measured waist circumference data and threshold cut-offs from Canadian health surveys conducted in 1981, 1988 and 2007–2009, the prevalence of abdominal obesity increased from 11.4% to 14.2% to 35.6%, respectively. Differences in waist circumference by sex are also reported. Over this time period men’s average waist circumference increased by 6.5 cm while for women the average increase was 10.6 cm. Temporal changes in obesity, based on waist circumference, are more pronounced than changes in BMI. In 1981, for each unit increase in BMI, the equivalent increase in waist circumference was 1.98 cm compared to in 2007–2009, when a unit increase in BMI was equivalent to an increase in waist
circumference of 2.22 cm. In adults affected by obesity, 93% have a waist circumference that places them at an increased health risk. These data illustrate that the obesity phenotype or what obesity looks like may be changing and the risks associated with this change in abdominal obesity may be even more significant and place a larger burden on individuals, the health system and society than increasing health risk associated with BMI.
In Canada, the prevalence of excess body weight (overweight and obesity) in children (six to 17 years) has increased over the last four decades. Using the World Health Organization criteria for children,24 the prevalence of overweight and obesity increased from 23.3% in 1978/79 to 31.4% in 2014. However, similar to adult trends, data from the last 10 years suggest the prevalence of overweight and obesity in children may have stabilized. Excess body weight differs significantly in children depending on sex, level of household income and place of residence. For example, obesity rates are higher: among 12–17-year-old boys (16.2%) than girls of the same age (9.3%), and in lower household income children (16.9%) than in higher income households (9.3%). Further, regional variations exist; in some regions of Canada the prevalence of overweight and obesity is 28.9%, while in others it is 65%.
Excerpted from: Epidemiology of Adult Obesity (from the 2020 Canadian Adult Obesity Clinical Practice Guidelines).
Click the image below to see our infographic on why obesity is a highly genetic disease.
