Obesity: Health Risks

by Health Canada

The number of Canadians who are overweight or obese has increased dramatically over the past 25 years. Obesity is a risk factor in a number of chronic diseases. Achieving and maintaining a healthy weight is important to reduce the risk of those diseases and improve overall health.

Although smoking remains the greatest threat to public health in Canada, poor eating habits, physical inactivity and their contribution to obesity are also critical public health challenges. Statistics Canada reports that two out of every three adults in Canada are overweight or obese.

The proportion of obese children has nearly tripled in the last 25 years. The increases were seen for both boys and girls and across all age groups except pre-schoolers. As well, more than half of Canadian children and youth are not active enough for optimal growth and development.

Many factors have contributed to the increasing rates of overweight and obesity. Changes in society, work and leisure have affected activity and eating patterns, leading to a rise in overweight and obesity. There has been a shift towards less physically demanding work, as well as an increased use of automated transport and passive leisure activities, such as television viewing and playing video games. Many children and youth have fewer opportunities to be physically active at school as physical education classes and time spent being physically active at school have been reduced. There are also fewer children and youth walking to and from school. Statistics Canada found a direct correlation between the amount of time youth spent watching TV and playing video games, and their likelihood of being overweight or obese.

Changes in our food environment, including consuming larger portion sizes and the availability of a wide variety of inexpensive food, have also made it challenging to maintain a healthy weight.

The body mass index (BMI) and waist circumference (WC) measurement are two tools used by health professionals to help assess your risk of developing health problems associated with being overweight and underweight. These tools are used with adults age 18 years and over, with the exception of pregnant and breastfeeding women. The BMI and WC may underestimate or overestimate health risks in certain adults, such as:

• highly muscular adults
• adults who have a very lean body build
• young adults who have not reached full growth
• adults over 65 years of age.

The BMI is a ratio of weight-to-height. It is not a direct measure of body fat but it is an indicator of health risk associated with being under- and overweight. Research conducted with large groups of people have shown that the BMI can be classified into ranges associated with health risk. There are four categories of BMI ranges in the Canadian weight classification system. These are:

• underweight (less than 18.5)
• normal weight (between 18.5 and 24.9)
• overweight (between 25 and 29.9)
• obese (30 and over)

To calculate your BMI and level of risk, use the link provided in the Need More Info? section or see your doctor.

The WC measurement is an indicator of health risk associated with abdominal obesity. Excess fat around the waist and upper body (also described as an "apple" body shape) is associated with greater health risk than fat located more in the hip and thigh areas (described as a "pear" body shape).

A WC measurement of 102 cm (40 in.) or more for men, and 88 cm (35 in.) or more for women, is associated with an increased risk of developing health problems such as Type 2 diabetes, coronary heart disease and high blood pressure. As the cut-off points are approximate, a WC just below these measurements should also be taken seriously. In general, your risk of developing health problems increases as your WC measurement increases above the cut-off points.

Your age, family history and the presence of other health conditions, such as high cholesterol, high blood pressure or high blood sugar levels can all interact with being overweight or obese to greatly elevate your risk of developing a wide range of chronic diseases. Poor eating habits, physical inactivity, and tobacco use not only contribute to the development of these conditions, they can further exacerbate their burden on your health.

Health Risks of Obesity

If you are overweight or obese, you may be at risk for a wide range of serious diseases and conditions including:

• hypertension or high blood pressure
• coronary heart disease
• Type 2 diabetes
• stroke
• gallbladder disease
• osteoarthritis
• sleep apnea and other breathing problems
• some cancers such as breast, colon and endometrial cancer
• mental health problems, such as low self-esteem and depression.

Obesity is one of the leading factors in heart disease and stroke, as well as in Type 2 diabetes, which affects an estimated 1.8 million Canadians. If you are overweight, you are at high risk of becoming obese, which can more seriously affect your health.

Minimizing Your Risk

You can achieve and maintain a healthy body weight by moderating the amount of food that you eat and by building physical activity into your daily life.

Get some regular physical activity that fits easily into your routine, such as a walk at lunch time. This recommended physical activity can be split up over several shorter sessions, if that suits you better (i.e., start with 10 minutes of activity, 3 times a day). For other ideas, check out the link to Canada's Physical Activity Guides to Healthy Active Living in the Need More Info? section.

Portion sizes affect the number of calories you consume. You may be eating more than you realize. Serve smaller portions and offer seconds to those who want more and avoid eating out in places where very large servings or "all you can eat" are offered. Alcoholic beverages and other sweetened beverages are also high in calories.

If you are concerned about your weight, consult your doctor or another health care professional for a more complete assessment of your weight and health risk. Discuss what your BMI and WC measurement mean for you as an individual.

Avoid fad diets. Although some may help you lose weight quickly, they usually involve avoiding certain types of food and the effects don't last once you return to a normal diet.

Government of Canada's Role

Health Canada and the Public Health Agency of Canada are committed to helping Canadians improve their health and well-being by promoting and supporting regular physical activity and healthy eating.

The Centre for Health Promotion is actively working with other levels of government, the private and voluntary sector on the issue of healthy living, which includes physical activity, healthy eating and healthy weights.

The Office of Nutrition Policy and Promotion supports the nutritional health and well-being of Canadians by defining, promoting and implementing evidence-based nutrition policies and standards.

The Food Directorate is the federal health authority responsible for establishing policies, setting standards and providing advice and information on the safety and nutritional value of food.

The Centre for Chronic Disease Prevention and Control works with stakeholders to provide leadership in chronic disease prevention and control across Canada and internationally.

About the Author

www.hc-sc.gc.ca
Health Canada is the Federal department responsible for helping Canadians maintain and improve their health, while respecting individual choices and circumstances.