Backgrounder: Healthy Weights Study


In 2004, the Chief Medical Officer of Health for Ontario reported an epidemic of overweight and obesity that is threatening the health of Ontario’s residents (Basrur, 2004). Halton Region has not escaped this trend. In Halton, 55% of residents aged 18 and over were considered overweight and obese in 2010 (Rapid Risk Factor Surveillance System, 2010, 2010 Body Mass Index (BMI) Indicator Report Adobe Portable Document Format (PDF)183KB). Unfortunately, this is not just a problem with adults. Increasingly children are becoming overweight and obese. In just 15 years, from 1981 to 1996, the prevalence of childhood overweight and obesity in Canada increased almost five-fold (Tremblay and Willms, 2003). This is particularly troubling because overweight and obese children are at increased risk for serious health problems, including heart disease, high cholesterol, high blood pressure, diabetes, osteoarthritis, and sleeping difficulties (Leung and Robson, 2008). In addition, young people who are overweight may suffer self-blame and low self-esteem because of the social stigma attached to being overweight (Leung and Robson, 2008). Despite well-known recommendations to be physically active and to eat nutritious foods, traditional health promotion that focused on individual behaviours has had only modest impact on the problem. A growing body of international public health evidence supports an increased emphasis on creating built environments1 where healthy nutrition and physical activity choices are the easiest choices.

In response to the 2004 Ontario Chief Medical Officer of Health report and the rates of overweight and obesity in Halton, the Halton Region Health Department promoted the initiative “Healthy Weights: Halton Takes Action” and brought together representatives from diverse sectors of the Halton community in June 2007 to explore causes and possible solutions to the overweight and obesity epidemic.

These community discussions identified 3 priorities:

  • to develop walkable and bikeable communities
  • to increase the availability of healthy food choices within the community
  • to ensure community coordination of the Healthy Weights Initiative

To complement this process, the Health Department partnered with academic researchers to generate new information about the built environment in Halton’s neighbourhoods and allow future evaluations of their change. The Healthy Weights Study aimed to examine the relationship between grade 7 students’ weights and various individual and community level factors that had been identified in the literature as important for physical activity and nutrition. The study found that the walkability scores in Halton were well below the rates of other denser areas. It also showed a significant association between Body Mass Index (BMI)2 and neighbourhood educational levels or individual-level risk factors such as physical activity, screen time, and eating breakfast. Other modifiable environmental-level risk factors were not found to be associated with BMI in this study.

The study results provide a baseline to inform program planning and future evaluations. However, the results from any study can only be interpreted properly with a good understanding of the setting of the study and the limitations of the study’s methods. Caution should be used in interpreting the findings of this study given the characteristics of Halton Region’s built and nutrition environments and its population. One of the study’s limitations is that it cannot be used to explore causality and determination. To do this, a research study needs variability in those variables being measured. Comparison across different groups according to diverse exposure levels is required to find any association. In addition, the evaluation of change over time is fundamental (pre- and post-risk exposure). By contrast, the Healthy Weights Study used a cross-sectional design, which examines only one point in time. This background paper provides an introduction to the Healthy Weights Study in Halton Region by focusing on the Region’s particular characteristics that need to be taken into account to interpret the study report:

  1. Halton is a relatively homogenous region with little variability in its physical activity and nutrition environment3.
  2. Rural areas are not adequately assessed with the indicators used in this study.
  3. Results from grade 7 students cannot be generalized to the general population.

The Healthy Weights Study in Context: Halton Region’s Characteristics

Halton is a relatively homogenous and affluent region

The Healthy Weights Study was completed in a largely affluent region composed of suburbs with little diversity in the built environment. The 2006 census showed that Halton was an affluent region with median incomes of families at over $92,000 in 2005, while the median family income for Ontario was $69,156 in the same year (Statistics Canada, 2007)4. In addition, a high level of education characterizes Halton's working-age population. Among the surrounding municipalities in southern Ontario, Halton had the highest percentage of persons with post-secondary education (Statistics Canada, 2006).

The built environment and physical activity

Halton is a suburban region whose built environment is characterized by its low density5  and limited diversity6. Much of Halton was built after 1950, when urban planning was focused on separating residential areas from places of work, suggesting that Halton is a classic example of a suburb that has been designed around vehicles. A lack of mixed-use zoning7 and low-density housing developments in Halton has resulted in suburban sprawl in many neighbourhoods. At the time of the Healthy Weights Study, Halton’s density was below the minimum threshold that research has found is needed in order to see a shift from vehicles to transit or active modes of travel (Frank and Pivo, 1995; Halton Region Health Department, 2009). The average population density of Halton is 457 persons per square km. Frank and Pivo (1995) found that nearly all travel was done by car until residential density levels reached 3,200 people per square kilometre (32 people per gross hectare). Conducting research on walkability in low-density suburbs is challenging because this style of development has led to a region with very little diversity in terms of built form8.    

The geographic units used for this study also limit the opportunity to compare across diverse sectors of the population. Halton’s 21 neighbourhoods were based on combined census tracts, which may have also reduced the variation between the neighbourhoods and therefore the ability to model variations related to Body Mass Index (BMI) (Leslie et al, 2007). Census tracts are relatively large geographic units in Halton. Differences in the built environment located in smaller areas than census tracts were not identified. This would have resulted in an “averaging” out of the walkability index and would have reduced any variation existing in smaller geographic areas across the Region.  

The nutrition environment

In terms of the “nutrition environment,” Halton Region’s relatively affluent and suburban characteristics are also fundamental to contextualize the study findings. The literature on adults in the United States has indicated that some more ethnically diverse and poorer neighbourhoods have less access to stores with fresh fruits and vegetables (Black & Macinko, 2008; Sallis & Glanz, 2006; Powell et al, 2007). Nonetheless, this literature may not apply to Canada (Apparicio et al, 2007, Smoyer-Tomic et al, 2006). While in the U.S. lower income neighbourhoods have been shown to have fewer larger supermarkets and farther distances for people to travel to get to them compared to wealthier neighbourhoods, it may be that all the neighbourhoods in Halton could be considered “wealthier,” resulting in little variability between the nutrition environments amongst neighbourhoods.

Most studies of the built environment have focused on comparing neighbourhoods that had a greater variability in population density and greater variability in diversity in neighbourhood design. It is difficult to meaningfully compare neighbourhoods that are ultimately very similar in terms of density and design and to expect to see associations with self-reported individual behaviour.

The lack of assessment of rural north Halton

An additional challenge to the Healthy Weights Study was the analysis of the Rural North Halton neighbourhood. This neighbourhood stands out from other neighbourhoods in the analysis and for good reason. Rural North Halton is predominantly green space and agricultural land. It has few sidewalks, the lowest density in the Region, and few diverse uses. In fact, there are different indicators for walkability in a rural setting that were not measured in this study, such as the presence of paved shoulders. Although density, diversity, and design are important characteristics for urban environments, these are not the same elements that would be important in a rural environment. In order to ensure Rural North Halton did not skew the multivariate model examining the factors influencing BMI, this neighbourhood was not included in the study; however, rural areas of other neighbourhoods, such as South Milton, were still included as places with some urban areas.

Results from grade 7 students cannot be generalized to the general population

Finally, much of the research linking the built environment and nutrition environment to overweight and obesity has been done among an adult population, whereas, this research studied grade 7 students. A study conducted by Zick et al. (2009) suggested that children and youth in non–low-income neighbourhoods are less constrained by their neighbourhood environment—such as the presence of a grocery store—because of their access to other options. The socioeconomic conditions in Halton Region further limit the possibility of generalizing results to the general population. This is probably the case in Halton Region, where the average family income is higher than in the rest of Ontario. Children and youth can more easily travel to purchase healthy food and have the money to purchase fresh fruits and vegetables.  Furthermore, children eat what their parents buy them to eat. In Halton Region’s affluent communities, parents tend to have access to cars. In general, the research literature on location of fresh food sources is not directly applicable to children (Galvez et al, 2009). A lack of walkable environments can also be offset by the ability of many Halton families to afford recreation programs for their children. The research report discusses some dimensions such as the mother’s education level, which may be also important in determining healthy behaviours in Halton Region.    


The Healthy Weights Study provides some valuable information for program planning and future evaluation to examine the relationship between children’s weights in Halton and various individual and community level factors.  In particular, it highlighted for future research factors such as low neighbourhood education levels and behavioural elements (i.e., high screen times, low physical activity, and infrequent breakfast). However, the study does not attempt to explore causal determination because other studies (Black and Macinko, 2010; Mujahid et al, 2007; Sallis and Glanz, 2009) have already shown that the built environment, physical activity, and healthy food intake are associated with overweight and obesity. This research is better conducted internationally, such as the work being done by the International Physical Activity and Environment Network (IPEN), as they are in a better position to locate communities with sufficient variability in the built environment. The lack of density and diversity in Halton is one of the factors that needs to be taken into account to better understand the study results. In addition, the fact that grade 7 students were the study population limits the generalizability of the research findings to the general population.

Despite its limitations, the report provides valuable information for grade 7 students in Halton Region. An important implication of the research is that changing the trend toward overweight and obesity is complex and one specific intervention will not change children’s weights at a population level in Halton. Healthy eating and physical activity programs that focus exclusively on individual knowledge and behaviour change are unlikely to be effective if the environment in which people live remains unchanged (Sallis and Glanz, 2009). Similarly, though it is almost certainly a necessary component, changing only the environment to support healthy eating and physical activity may not be sufficient to see a change in behaviour. The social-ecological model used in the study tells us that in order to be as effective as possible, we need to introduce and sustain programs at the individual, social, and community levels. To be successful, all relevant stakeholders, including community residents, need to be involved in efforts to create healthy individuals and environments. Community engagement is critical to the success of new initiatives (Sallis and Glanz, 2009).

For overweight and obesity prevention, children and youth are a priority population for policies and programs. Healthy eating and physical activity are key factors in healthy child development; behaviours and attitudes formed during childhood can last a lifetime (Ministry of Health Promotion, 2006). Overweight children are more likely to become obese adults with chronic health problems (Stovitz et al, 2010). It is believed that by supporting healthy and active children and youth, we will be able to build a culture of healthy eating and physical activity that will last for years to come. In addition, investments in reducing adolescent overweight and obesity will reduce future medical costs (Wang, Dennistron, Lee, Galuska, Lowry, 2010).


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1  The ‘built environment’ refers to patterns of human activity within the physical environment.  It includes elements such as the urban design, land use, and the transportation system (Halton Region Health Department, 2009).

2  Body Mass Index is the weight in kilograms divided by the squared height in metres. It is associated with weight-related health risk.

3  In this study, nutrition environment refers to the average distance to a fruit and vegetable store. However, in a broader context, a nutrition environment encompasses multiple dimensions such as culture, ethnicity and socioeconomic status, which affect the access to healthy food.

4  Census family total income: the total income of a census family is the sum of the total incomes of all members of that family.

5  Density refers to the number of households and jobs per hectare. Research shows that as density increases, people reduce their use of automobile, and increases the number of trips by walking, bicycling and public transit (Halton Region Health Department, 2009).

6  Diversity as it applies to the built environment makes reference to variety of housing and the presence of mixed land uses such as neighbourhood retail and service opportunities. Researched evidence has consistently shown that there is a relationship between diversity and active transportation such as walking and cycling (Halton Region Health Department, 2009).

7  Mixed use zoning is a form of development that combines two or more of the types of use: residential, commercial, office, industrial or institutional. Mixed-used zoning is an indicator of diversity (Halton Region Health Department, 2009).

8  Halton Region is also in constant change. In reviewing this study and comparing results to what is currently happening in communities across Halton, it is important to recognize that these data were collected in 2006. For instance, under-serviced areas such as South Georgetown have had new grocery stores built, and many new schools have been built across the entire Region. If this study was to be repeated, results may be different as communities continue to grow, and the built environment and nutrition environment continue to change.

This backgrounder is an adaptation of the original report by Kristie Daniel and Emma Tucker (2009), “Individual and environmental factors influencing obesity in suburban youth:  Results of the research conducted under Healthy Weights: Halton Takes Action” (Halton Region Health Department). The selection of excerpts and the final edition was conducted by Fabio Cabarcas, Senior Policy Analyst Chronic Disease Prevention (CDP), in collaboration with the following Halton Region Health Department staff members: Dr. Monir Taha, Associate Medical Officer of Health and Director Chronic Disease Prevention & Oral Health, Helen Ross, Manager CDP, Philippa Holowaty, Manager Epidemiology, and Jeffrey Crowder, Health Promoter CDP.