Monday, January 31, 2011

Orderly neighbourhoods with lots of green space good for the waistline?

Aesthetics of the residential environment is important for sustainability and even for obesity prevention as I alluded to in my introduction of sustainability on January 21st. I hesitantly categorized my discussion of ‘sustainability’ and how that relates to obesity into four separate posts, but you will find that the categories tend to blur together. Please keep that in mind as you read all posts in the series.

It’s probably a no-brainer that if your neighbourhood were to look like a dump, you would be less likely to be out and about being active. Well, the scientific literature is starting to catch up with common sense. Studies are finding that the presence of a lot of garbage, graffiti, derelict buildings, etc, in a neighbourhood tend to dissuade people from being physically active, and can actually increase their chances of being obese (1-3). There are a few explanations for why this might be; an obvious one is that if there is nothing interesting to look at, residents may not be enticed to go for a walk, or run, or use active transportation to get somewhere.  A run-down neighbourhood may also be perceived as dangerous, or may invite crime (perhaps you have heard of the ‘broken windows hypothesis’?) and actually be dangerous (4). This may prevent adult residents partaking in physical activity outside, and make moms leery of letting their children play outside.

Photo credit: W. Murphy

Stress can also result from living in a hazardous environment – stress has been shown to have direct effects on metabolism, and has been linked to obesity (2,5). Eating may also be used as a coping strategy for stress (6,7). Who hasn’t taken the Haagen Daas out after a stressful day at work? If you’re constantly stressed and have crappy, cheap food nearby that makes you happy, well then it’s not hard to overeat.

Dilapidated neighbourhoods likely do not have as many community residents looking out for their interests as say the Bridle Path in Toronto, the Glebe in Ottawa, or the Shaughnessy neighbourhood in West Vancouver.  These less cared for neighbourhoods, therefore, are prone to further environmental injustices such as illegal dumping.

I think, in addition to neighbourhoods that are not well cared for, we must also consider the mind-numbing monotony of suburban design. If I did not have a dog that did not require a walk two times a day, I would never walk around my neighbourhood just to ‘go for a walk.’  EVERYTHING LOOKS THE SAME!

Nearby greenery may also be important for the promotion of physical activity and prevention of obesity (I recently twittered about a new way to measure the quality of open space in neighbourhoods using Google Earth – Come, to think of it that may end up being my last PhD thesis paper…)  A study that used data from eight different European countries found that living in an area with a lot of greenery (objectively measured) increased the odds of adult residents participating in physical activity by quite a large amount (3.32-fold to be exact), compared to low greenery areas (8). High greenery areas also reduced the odds of obesity by 40%.  Associations among children are similar but less strong than they are in adults (9,10). 

Perceived greenery on the other hand, may be more important than objectively measured greenery; for instance, one study found an association between walking trips per month and the amount of greenery residents perceived, but not with that measured by the researchers (11). Population density may also be important as some studies have shown that greenery is not important in rural areas (12) or areas where other amenities are not that easily accessible on foot (11).

Photo credit: F. Grammenos
In addition to obesity prevention, greenery is beneficial for overall well-being. A study conducted in the UK found that people who were more dissatisfied with the green spaces in their neighbourhood were more likely to score lower on the mental health and vitality scales of the SF-36, than those who were not dissatisfied (13). Cognitive function has even been shown to improve among low-income children when they are provided with window views of greenery, in contrast to paved or bare dirt surfaces(14). Interestingly enough, a cross-Canada run is now underway to get Canadian children outside to play and learn - go Colin!  

In summary, if we like the way our neighbourhoods look we may be more likely to be physically active and less likely to be obese. Neighbourhoods that are cared for and regularly used are more sustainable, and more greenery can help to recycle the harmful outputs of urban/suburban living.   


  1. Grafova IB. Overweight children: Assessing the contribution of the built environment. Preventive Medicine. 2008; 47(3): 304-8 
  2. Stafford M, et al. Pathways to obesity: Identifying local, modifiable determinants of physical activity and diet. Social Science & Medicine. 2007; 62: 1882-97 
  3. Saelens BE & Handy SL. Built environment correlates of walking: A review. Medicine & Science in Sport Exercise. 2008; 40(7S): S550-66 
  4. Macintyre S. et al. Place effects on health: How can we conceptualise, operationalise, and measure them? Social Science & Medicine. 2002; 55(1): 125-39 
  5. McEwen BS. Protective and damaging effects of stress mediators. New England Journal of Medicine 1998;338(3):171-9. 
  6. Kumanyika SK. Environmental influences on childhood obesity: ethnic and cultural influences in context. Physiology & Behavior 2008;94(1):61-70. 
  7. Rosenkranz RR, Dzewaltowski DA. Model of the home food environment pertaining to childhood obesity. Nutrition Reviews 2008;66(3):123-40. 
  8. Ellaway A. et al. Graffiti, greenery, and obesity in adults: secondary analysis of European cross sectional survey. BMJ. 2005; 331:611-2 
  9. Bell JF et al. Neighborhood greenness and 2-year changes in body mass index of children and youth. American Journal of Preventive Medicine 2008;35(6):547-53 
  10. Wheeler BW et al. Greenspace and children’s physical activity: A GPS/GIS analysis of the PEACH project 
  11. Tilt JH et al. Using objective and subjective measures of neighbourhood greenness and accessible destinations for understanding walking trips and BMI in Seattle, Washington. American Journal of Health Promotion. 2007; 21(4): 371-79 
  12. Liu GC et al. Green neighborhoods, food retail and childhood overweight: differences by population density. American Journal of Health Promotion 2007;21(4 Suppl):317-25. 
  13. Guite HF, Clark C, Ackrill G. The impact of the physical and urban environment on mental well-being. Public Health 2006;120(12):1117-26. 
  14. Wells NM. At home with nature: effects of "greenness"on children's cognitive functioning. Environmental Behavior 2000;32(6):775-95. 

Friday, January 21, 2011

Sustainable Design, what does that even mean? Health by Design continues...

In urban ecology, human settlements are seen as dynamic ecosystems whose structures are defined by the built and natural environments, population demographics, social institutions, and culture, as well as belief, economic, and political systems (1). They are dissipative structures, meaning that they require huge inputs of energy, and produce amounts of waste in proportion to the materials they consume.  From reading the literature in this field, human settlements seem to be akin to parasites, in that they undermine the very ecosystems that support them. I would tend to agree with this perspective.

From this “city as ecosystem” perspective, the doctrine of sustainability has emerged, and revolves around the concept of ‘the three Es’ - Environment, Economy, and social Equity. Sustainable neighbourhood development then refers to the balanced consideration of environmental, social and economic goals, with specific objectives that include minimizing environmental impact, sustaining a high quality of life, and financing infrastructure in an equitable and efficient manner (2) – so that humans and their settlements can exist well into the future.
automobiles,cities,commuters,environmental issues,freeways,iStockphoto,public transportation,roads,rush hour,traffic
It should by now be quite apparent that our current space gobbling method for designing communities is environmentally (and in some instances, financially) unsustainable – see Health by Design: Part 1. However, if you need more convincing I can humour you with some extra facts and figures. In Canada for instance, passenger travel has increased by 30% (passenger km traveled per capita) from 1990 – 2008, and we travel mostly by personal passenger vehicle, not public transportation (85% of all ground-based transportation in 2008)(3). Increasing passenger vehicle use has led to an unprecedented rise in GHG emissions in Canada (and North America) – it now contributes 20% of all GHG emissions in Canada (3).     Suburban sprawl also requires the continual creation of paved roadways that often disrupt and damage human communities, as well as natural ecosystems, which have the capacity to recycle harmful outputs of suburban living (4). Increasing paved surfaces also increases water runoff, which increases the chance of raw sewage flowing directly into lakes and rivers when storm sewers are overwhelmed. As an aside, New York is now having to deal with aging infrastructure and is considering going green for the environment and its pocket book. Finally, a large bulk of infrastructure funding is diverted to road repair, financing that could be spent elsewhere to improve neighbourhood liveability. 

A sustainable neighbourhood design is, by its very nature, obesity preventive. The series Health by Design was originally supposed to be two posts, but I realized that I should probably more fully explain the characteristics of a sustainable neighbourhood design and how that relates to obesity prevention before I started discussing the effectiveness of the Fused Grid design. Since no one likes long posts, I’ll divide this into a series of four posts that focus on aesthetics, safety, diversity and compactness, and connectivity. This first post (coming soon) will begin with aesthetics.    

(1) Grimm N, Baker LJ, Hope D. An ecosystem approach to understanding cities: Familiar foundations and unchartered frontiers. In: Berkowitz AR, Nilon CH, Hollweg KS, editors. Understanding urban ecosystems: A new frontier for science and education.New York: Springer-Verlag; 1999. p. 95-105

(2) Jabareen YR. Sustainable urban forms: Their typologies, models, and concepts. Journal of Planning Education and Research 2006;26:38-52.
(3) Environment Canada. National Inventory Report: 1990-2008 Part I. Greenhouse gas sources and sinks in Canada: The Canadian Government's Submission to the UN Framework Convention on Climate Change. Available at:

(4)  Lopez R, Hynes HP. Obesity, physical activity, and the urban environment: public health research needs. Environmental Health: A Global Access Science Source 2006;5(1):25-32.

Tuesday, January 11, 2011

Governments play a role in deciding how we eat, citizens can play a role in government

Marion Nestle is a professor in nutrition, public health, and sociology at New York University.  She writes extensively on food policy issues and her research focuses on how science and society influence dietary advice and practice. She is the author of many books and currently writes a monthly Food Matters column for the San Francisco Chronicle, and blogs daily at and at the Atlantic Food ChannelHer most recent Food Politics post struck a chord with me and I wanted to share it:

'When San Francisco voted to eliminate toys from McDonald’s Happy Meals, the Forum at the Harvard School of Public Health invited comments on this issue.  Here’s what I had to say about it:
I’m surprised at the mayor’s comment that “parents, not politicians, should decide what their children eat,” because the San Francisco ordinance is not about the food. It’s about the toys.
Nobody is stopping parents from ordering Happy Meals for their kids. But as everyone knows, kids only want Happy Meals because of the toys.
The idea that government has no role in food choice is ludicrous. The government is intimately involved in food choices through policies that make the cost of some foods—those containing subsidized corn or soybeans, for example—cheaper than others.
It is not an accident that five dollars at McDonald’s will buy you five hamburgers or only one salad. It is not an accident that the indexed price of fruits and vegetables has increased by 40% since the early 1980s, whereas the indexed price of sodas has decreased by 30%. Right now, agricultural policies support our present industrialized food system and strongly discourage innovation and consumption of relatively unprocessed foods.
Agricultural policies are the results of political decisions that can be changed by political will. If we want agricultural policies aligned with health policies—and I certainly do—we need to exercise our democratic rights as citizens and push for changes that are healthier for people and the planet.
Yes, individuals are the ultimate arbiters of food choice. But our present food system makes unhealthful eating the default. We need to be working for government policies that make healthy eating the default. The San Francisco ordinance is a small step in that direction'.

I 100% agree with you Marion.  And I hope that others will soon come to understand and be concerned with this.

But how can we, as ordinary citizens, make a difference in the politics of our respective countries?  I think that it IS possible, but this is a rather lengthy discussion for another day or two or three...  

However, I would like to leave you with one last thought on this: 

In order to even begin making a difference, we need to first know where political parties stand on issues of interest (i.e. food policies), and then actually go out and VOTE! In our last Canadian election (2008), only 59% of the eligible population voted. Voter turnout has been on the decline and this 2008 proportion is the lowest on record. Even more concerning is that voter turnout is lowest in the youngest age groups,the so-called future of this country...