Obesity in Canada

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Opportunities for Intervention

The main focus of this report has been to highlight new data and findings concerning the prevalence of obesity in Canada, as well as to summarize our current understanding of its determinants and the health and economic burden. It states what we know about the issue. This chapter will highlight some promising evidence-based practices and opportunities for obesity prevention and management described in the national and international literature.

General principles

Even though scientific knowledge is still evolving and incomplete, waiting for the “perfect solution” may not be an option, and decisions about how best to address obesity at a population level must be made.^124,125 Such decisions may benefit from careful analysis of the feasibility of possible interventions, the available scientific evidence, the cost/benefit ratio (including the potential for unintended or negative outcomes such as stigmatization¹²⁶ or increased inequities¹²⁷), as well as potential value for money.¹²⁸ In discussing actions to address childhood obesity in particular, Estabrooks, Fisher and Hayman make the point that interventions must carefully document not only outcomes, cost and robustness but also the broader legislative or community context, implementation issues and sustainability.¹²⁹

Approaches to combat obesity can be categorized into three streams:¹³⁰

1. health services and clinical interventions that target individuals,
2. community-level interventions that directly influence behaviours, and
3. public policies that target broad social or environmental determinants.

In practice, these are not mutually exclusive categories but, rather, overlapping and complementary lines of action.

The WHO recommends a number of core principles to underpin public health efforts against obesity:

• ensuring that they are of adequate duration and persistency;
• adopting a slow and staged approach over time to support the transition through the stages of change (i.e., awareness, motivation to change, experimentation, adopting a change and maintaining the changed behaviour);
• providing education to encourage and support changes in behaviour and attitudes;
• harnessing advocacy from respected elements of society;
• fostering shared responsibility for change among consumers, communities, industry and governments; and
• utilizing legislative action where appropriate.⁶

Individual-based interventions

The 2006 Canadian clinical practice guidelines on the management and prevention of obesity in adults and children provide recommendations for health care professionals regarding the prevention, screening and management of obesity in clinical and community health settings.²² The guidelines suggest that approaches be tailored to individual patients but can include one or more of the following:

• behaviour modification training or therapy, including family-oriented behaviour therapy for children;^47,131
• dietary interventions, such as an energy-reduced diet;^132,133
• regular physical activity in adults;¹³⁴
• combined dietary and physical activity therapy;^135,136 and
• for some individuals, bariatric surgery and prescription medications.^137-138

A 2009 Cochrane Collaboration review of health professionals’ management of overweight and obesity suggested that brief training sessions, shared care with other health professionals and dietitian-led programs may be worth further investigation to demonstrate how the practice or organization of care could be improved.¹³⁹

There is some evidence that face-to-face (e.g., individual or small-group) clinical counselling is more effective than remote communications (e.g., telephone or mail-based programs) in obesity prevention in adults.¹⁴⁰ Emerging evidence on Internet-based programs suggests that computer-tailored approaches show inconsistent results but have been associated with changes in physical activity, diet and/or weight loss in adults.^141,142 There is only limited evidence to guide obesity screening and management programs for children and youth.¹⁴³

While individual interventions may be effective in promoting weight loss, avoiding weight regain is frequently a challenge.¹⁴⁴ For example, a US follow-up study of approximately 1,300 overweight or obese individuals aged 20-84 years who had lost at least 10% of their body weight found that, by one year, 34% had regained more than 5%.¹⁴⁵ Self-monitoring (e.g., frequent self-weighing) and regular physical activity may help to avoid weight regain,¹⁴⁶ and one study has suggested that even a relatively inexpensive intervention such as nurse counselling and support can help to prevent relapse.¹⁴⁷ However, frequent self-weighing has also been associated with increased risk of binge eating and unhealthy weight control among adolescent girls.¹⁴⁸

Community-based interventions

Community-based obesity prevention interventions include programs delivered in key settings, such as workplaces and schools, as well as both targeted and universal public educational and information campaigns delivered through print, broadcast and online media. One example of a comprehensive campaign that targets multiple risk factors (e.g., physical inactivity, low fruit and vegetable consumption, smoking, overweight and obesity, and alcohol use during pregnancy) is British Columbia’s ActNow BC. For each factor, specific targets are pursued through a mix of collaborative strategies and mechanisms. For example, from 2005 to 2010, ActNowBC set a target to reduce by 20% the proportion of the population 18 and over who were overweight or obese from the 2003 estimate of 42.3%.¹⁴⁹

Social marketing campaigns that emphasize physical activity, healthy eating and/or healthy weights are one type of common community-level health promotion tool. Some examples of social marketing campaigns that use mass media strategies are Canada’s ParticipACTION (physical activity)^150,151 and 5 to 10 a Day (fruit and vegetable consumption),¹⁵² England’s Fighting Fat, Fighting Fit¹⁵³ (revised as Change4Life¹⁵⁴), Australia’s Measure Up campaign¹⁵⁵ (healthy weights), and US campaigns such as the VERB¹⁵⁶ (youth physical activity) and Fruits & Veggies More Matters¹⁵⁷ (previously known as 5 A Day). Evaluations have not been published for all campaigns; among those that have, the type of evidence collected has varied. Some evaluations have focused almost exclusively on measuring campaign awareness, public attitudes and knowledge,¹⁵⁸ whereas others have focused on the specific behaviour being targeted, such as physical activity within a specific target population.¹⁵⁹ Fighting Fat, Fighting Fit is one of the few campaigns that have been evaluated for impact on participants’ body weight; results, although encouraging, were modest.¹⁵³ Further study is required to more clearly understand the contribution that mass media campaigns can make to obesity prevention or management, as well as the manner by which they influence behaviour.

A recent systematic review of experimental and quasi-experimental studies, conducted primarily in the US, identified a number of initiatives that were effective in influencing two of the key behavioural factors known to affect obesity: physical activity and healthy eating.¹⁶⁰ The most promising approaches included the following:

• point-of-decision prompts such as signage encouraging the use of stairs;
• school-based interventions for children and youth (e.g., increased frequency/duration of physical education classes, additional training for teachers);
• comprehensive worksite programs that include counselling, education, incentives and access to supportive facilities such as locker rooms, showers and gyms;
• point-of-purchase strategies, such as menu and shelf labelling, to increase the purchase and consumption of healthier foods;
• workplace, school and municipal policies and environmental supports that increase access to healthier foods and beverages (e.g., in vending machines restaurants and cafeterias);
• systematic nutrition reminders and training for health care providers.¹⁶⁰

It has been argued that a strong business case can be made for workplace wellness programs.¹⁶¹ A review of 12 Canadian worksite programs reported a wide range of activities, such as addressing the physical work environment (e.g., safety/cleanliness, air quality, ergonomics, health and safety), the physical health of employees (fitness, smoking cessation, nutrition and lifestyle education or promotion) and mental health, stress and other psycho-social concerns (including work/family balance, work organization and stress reduction).¹⁶² It has been reported that obesity is becoming an increasing focus of workplace wellness programs.¹⁶³ A recent meta-analysis of nine randomized controlled trials of such programs reported a net loss of 2.8 pounds at 6-12 months, with six trials showing a net reduction in BMI of 0.47.¹⁶⁴

A 2006 review of 158 publications representing 147 studies of obesity prevention and management interventions for children and youth concluded that the majority led to positive outcomes, at least in the short term.¹⁶⁵ Targeted programs in clinical settings most frequently reported positive outcomes, and school-based programs, particularly those conducted in primary schools, were also found to be effective. Engagement in physical activity was considered a critical component of effective obesity prevention and management programs.¹⁶⁵

The review paper concluded with a call for greater recognition of the roles that sex and gender, family dynamics and environment can play in childhood and adolescent obesity. It also highlighted a number of weaknesses in the current evidence base:

• little or no research on interventions for preschool-aged children, sex-specific interventions or interventions focusing on immigrant children and youth;
• under-utilization of the principles of population health;
• little stakeholder involvement;
• little or no investment in environmental modifications (with the exception of some school-based programs); and
• a focus on obesity in isolation, rather than as part of an integrated chronic disease prevention approach.¹⁶⁵

Other studies have also shown that school-based health programs have the potential to educate children and youth about nutrition and healthy eating, and promote behaviours (e.g., physical activity and eating) related to achieving or maintaining a healthy weight.^166-168 Reviews of past studies, however, have produced mixed results in terms of effectiveness.^169-171

Public policies

The effectiveness of public health efforts to promote healthy weight by encouraging individuals and families to make healthier choices is often limited by factors in the physical, social and economic environments that preclude or undermine those choices. For example, analyses suggest that even after adjusting for behavioural and individual factors, living in a neighbourhood characterized by material deprivation is associated with a higher BMI for women, though not for men,¹⁷² and that participation in organized sports is more prevalent among children from higher-income than lower-income households.¹⁷³ Studies from other jurisdictions have suggested that environmental factors, such as the lack of safe and accessible spaces for children to play¹⁷⁴ and a built environment that promotes motorized transportation over active commuting (cycling and walking),¹⁷⁵ can serve as barriers to physical activity. It has also been suggested that environmental factors may be linked to food choices, diet quality and obesity.¹⁷⁶

A number of reports have commented on the connections between land use planning and health.^177,178 It has been suggested that progress can be made in combating obesity by broadening public health efforts into comprehensive strategies that both promote healthy choices and simultaneously support environmental changes to make those choices easier.¹⁶⁶ Many municipalities have reported that broad stakeholder consultation is needed in order to balance environmental, economic, social and cultural needs and to manage and coordinate community planning and design.¹⁷⁹ Such approaches often require leadership by various levels of government, as well as a commitment to a long-term, multisectoral and progressive approach that is rooted in an ecological or environmental perspective.^47,180

Some examples of the types of public policy strategy that have been discussed or implemented to address the key influence on obesity, physical activity and nutrition are as follows:

• Subsidy programs to support healthy eating (e.g., the Food Mail Program for northern Canada,¹⁸¹ the Northern Fruit and Vegetable Pilot Programme in Ontario¹⁸² and community-based food security initiatives¹⁸³);
• Land development, urban planning and transportation planning that promote active commuting and recreational physical activity;^6,166
• Food labelling to help consumers understand the health implications of their choices;^6,166
• Regulation of marketing to children, particularly for energy-dense, nutrient-poor foods and beverages;^6,166,184
• Financial incentives to promote physical activity (e.g., the Children’s Fitness Tax Credit and the Federal Tax Credit for Public Transit^185-187); and
• Financial disincentives, such as a tax on “unhealthy” foods and beverages.¹⁸⁸

It is unlikely that there is a single solution to reverse the rising prevalence of obesity in Canada; a comprehensive, multisectoral approach may be needed to respond effectively to this complex issue. A number of resources are available to assist policy-makers and health practitioners in assessing the evidence for potential population-based obesity prevention and management interventions (see Appendix 4). Evidence from smoking cessation programs and other public health experiences suggest that an intervention is more likely to be effective if it is long term and multifaceted in nature, tackling multiple drivers and factors simultaneously.¹⁸⁹ Responses may also be improved by integrating evaluation into program development and implementation. By facilitating the emergence of new knowledge, ongoing evaluations could support the continual realignment and enhancement of resource investments.¹⁸⁹

Research issues

Relatively few population-level obesity prevention and management interventions, especially public policy approaches that target broader environmental factors, have been systematically evaluated either for their effectiveness or cost-effectiveness.¹⁹⁰ The need for more research is particularly pressing for obesity prevention, for which evidence of efficacy is limited to a small number of studies.¹⁹¹ Developing and implementing effective interventions requires better knowledge about what approaches work (and do not work) in different settings and with different populations,¹⁹² as well as economic analyses to assess value for money.¹²⁸

More research is needed on how best to address obesity in specific target groups. For example, while current knowledge about interventions among children and youth is growing, a number of gaps remain, particularly for preschool-aged children. More information is also needed about the efficacy of interventions among immigrants, those living in economically deprived neighbourhoods and Aboriginal communities. Given the results of the multifactorial research presented earlier in this report, more information about the effects of intervention by sex, as well as the impact of sex-specific initiatives, could also offer important insights for program planners and policy-makers.

Key points

• Approaches to combating obesity can be categorized into three main types: 1) health services and clinical interventions that target individuals, 2) community-level intervention to influence behaviours, and 3) public policies that target broad social or environmental determinants.
• Guidelines suggest that a number of individual-based interventions can contribute to obesity prevention and management but that more evidence is currently available for interventions targeting adults than children. Moreover, weight maintenance (i.e., avoiding weight regain) is frequently a challenge.
• Community-based obesity interventions are delivered in the community and settings such as workplaces and schools. An example of a Canadian community-based intervention is ActNow BC.
• Systematic reviews and policy documents have identified some of the key principles and strategies for community-based interventions.
• The literature also suggests that a number of public policy approaches can be undertaken to address obesity at the population level.
• There is unlikely to be a single solution that will reverse the rising prevalence of obesity in Canada; rather, a comprehensive, multisectoral response may be needed.
• More research and information are needed about the effectiveness, transferability and generalizability, and value for money of prevention and management interventions, particularly in specific subgroups such as preschool-aged children, immigrants and Aboriginal communities. Given the results of the multifactorial analysis of the population attributable risk of obesity, additional research on the sex-specific effects of interventions could also offer important insights.

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