07/25/2011 01:55 EDT | Updated 09/23/2011 05:12 EDT

To Fight Obesity, Use Homes and Cities as Exercise Machines

Why do waistlines keep expanding? The common tendency is to blame people's poor dietary choices, made worse by their inactivity. But if one is to point out the main culprits of our effort-free habits, the motor vehicle and suburbia would be the ones.

The global obesity epidemic is staggering, and it seems to keep escalating. In Canada, where I live, one person in five is overweight and nearly one in 10 is obese, an increase of two-and-a-half-times over the past two decades, according to the Canadian Institute for Health Information.

Obesity among Canadian children is particularly troubling. In the past three decades, the rates have almost tripled. We are giving rise to the next generation of patients who will populate hospital wards in the coming decades. Efforts to curb the trend have proven unsuccessful.

The medical consequences of obesity are well documented. A New England Journal of Medicine paper suggests that overweight and obese people run a fivefold risk of diabetes, and have greater risk of hypertension, gallbladder disease, and certain cancers. The author also suggests that the overall risk of mortality increases by two and half times.

So why do waistlines keep expanding? The common tendency is to blame people's poor dietary choices, made worse by their inactivity. Only recently attention was given to a sobering fact: our built environment has been progressively altered to curtail physical activity, even by those who wish to be active. Over the past century, we have planned communities, built homes and welcomed lifestyles that lets us run daily chores while burning fewer and fewer calories.

If one is to point out the main culprits of our effort-free habits, the motor vehicle and suburbia would be the ones. Some 65 per cent of all North Americans live in suburban or rural locations. That means that nearly all work, shopping, social, educational and entertainment-related activities require use of private cars by every member of the household. We simply reduce walking to a bare minimum.

Low residential density, the mark of most new suburbs, implies that basic services and amenities, that can potentially get people active, are not economically viable in the suburbs. There are not sufficient riders to justify introduction of a public transit and not enough shoppers to support a corner grocery store, for example. Things have gone from bad to worse when it comes to public health implications of town planning decisions.

In the name of efficiency, schools have been relocated from their traditional spots in the heart of neighbourhoods to the outskirts where they can easily be accessed by residents of several communities. That meant that a short walk or an easy bike ride to them by a pupil has been rendered impossible. Unfortunately, the time allocated to physical activity has also been sharply reduced. In Canada, it stands on one hour per week, far less than what's needed to let a child burn acceptable number of calorie.

Another casualty of contemporary suburban planning was the sidewalk. Since no one walks, some argued, why are they needed at all? Seniors, parents pushing a stroller and children had to share the road with motorists, often putting their lives at risk. When the sidewalk vanished, benches followed, leaving no places to sit on, or trees to stand under and talk with a neighbour on a sunny day. Stepping out for a simple healthy walk became uncomfortable.

At home, physical activity has also experienced a sharp decline. When asked, most people will rather reside in a dwelling with fewer stairs, limiting a dose of essential healthy exercise. They have also acquired effort-free tools like mechanized lawn mowers or snow blowers. The kitchen has also become a place for the storage of gizmos which have replaced domestic manual labour. We are simply spending fewer calories after work as well.

So, how should we get people to be active? The simple answer is to recast in our built environment the features that have, over the past half century, been taken out. Homes and cities must be regarded as exercise machines. Along with the reintroduction of physical changes, we have also continued to warn people about the grim consequences of inactive lifestyles. Several strategies nonetheless need to be placed on top of planning agendas.

The tide is beginning to change. Elected and public health officials are finally recognizing the link between poor urban planning and its unhealthy consequences. In recent years, I consulted established towns and designed new ones based on active living principles. In the Town of Stony Plain in the Province of Alberta, Canada, we have configured a master plan for healthy living. Organic growth ensures that the towns' centre could be reached by walking or safe cycling from every home. Sidewalks, bike paths and traffic calming features are made part of every street. Places for commerce have been allocated in every neighbourhood. A new civic square that functions as a gathering spot has been introduced in front of the town hall. Free shuttle buses that reach all neighbourhoods have also been proposed. A series of green open spaces have been connected to provide a secondary, more leisurely way of moving around. Mixed types of dwellings, some with commerce on their ground floors, are now part of the urban vocabulary.

It takes time to bring about changes in town planning. Convincing elected officials about the need to invest in health promotion is not simple. Our conduct, however, must be an urgent one, because if not followed, the ramifications to people and nations can bear dire consequences.