Obesity in Canada – Introduction

Introduction

The causes of, and contributors to, obesity are complex and multifaceted. They include not only individual choices (what to eat and whether to be active) but also environmental and social determinants that shape people’s ability to make healthier choices. Our understanding of the underlying factors that contribute to obesity is often incomplete, spread out between different studies and research findings.

This report pulls together both new data analyses on the prevalence, determinants and impacts of obesity, as well as a summary of recent research reviewing what we know about obesity in Canada. The report will also provide an overview of obesity prevention and treatment.

While overweight is recognized as both a precursor to obesity and a health concern in its own right, this report will focus primarily on obesity (class I through III), as this is the weight class associated with the greatest health risks. New analyses discussed in this report include an updated estimate of the societal cost of obesity, updated obesity estimates from the 2007/08 Canadian Community Health Survey (CCHS) and the 2006 Aboriginal Peoples Survey, and research on behavioural and social factors contributing to obesity. These analyses are presented within the context of other Canadian research, including findings from the 2007-2009 Canadian Health Measures Survey, published analyses of previous health surveys, reviews by the Canadian Institute for Health Information (CIHI) and a scan of the related medical and scientific research literature on obesity among Canadian populations. In the case of Aboriginal peoples, the scan was extended to include studies that investigated diabetes or other chronic conditions and collected data on body weight as part of the research protocol.

This combination of new and existing analyses aims to provide an overview for health planners, promoters and decision-makers of what is currently known about the prevalence, determinants and impacts of obesity in Canada.

Box 1. Measuring Obesity in Canada: Key Population Health Surveys

Canadian Health Measures Survey (CHMS) The CHMS is an extensive national survey of physical health measures, collected through interview as well as direct measurement, capturing height and weight, fitness, flexibility, muscular strength and many other health and environmental elements. Data were collected from approximately 5,600 people aged 6 to 79 years at 15 sites across Canada between March 2007 and February 2009; the results are considered representative at the national level.Footnote 1 

Canadian Community Health Survey (CCHS) Information is collected from about 65,000 respondents aged 12 and over, including Aboriginal peoples living off-reserve, and is reported annually starting in 2007. Previously, the sample consisted of 130,000 respondents every two years. In order to achieve more accurate estimates for smaller populations, in this report 2007 and 2008 samples were pooled together and used for most analyses unless trends or measured height and weight data were required. Height and weight measures were collected most recently in 2008 and 2005 for a subsample of respondents. In a 2004 cycle focusing on nutrition, measured height and weight were also collected for approximately 20,000 respondents aged 2 and over. For more detail on the CCHS see Appendix 1.

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