walk it off

Planners regularly cite the importance of arranging land uses to reduce trip distances. For example, if neighbourhood shops are not isolated from residential areas, shorter distances increase the likelihood that people will travel on foot. Or if apartments are close to public transport routes, more can take the bus to work. There are many reasons for encouraging this, including the need to reduce the costs of widening roads and providing parking. The December 2003 edition of the Sustainable Transportation Monitor provides a new twist to this theme. Let me explain.

There are conflicting reports on why obesity is a growing problem worldwide. In general, our weight is determined by energy intake - specifically the consumption of fat in food - and energy expenditure through physical activity. Studies conducted in several countries suggest that energy intake from fat in food has declined, while body weights have been increasing. So we must be less active, right? Maybe, but is the focus of remedial actions making a difference?

In Canada, as far as health and exercise is concerned, the focus has been on organized activity such as physical education in schools. However, for some groups of the population, the rate of organized or deliberate physical activity appears to have remain unchanged or even increased, and yet body weights continue to rise. A possible explanation relates to the role of transportation - and the associated matter of urban form. Shorter trip lengths and the use of public transport increase physical activity, because they both can include walking.

One study has shown a correlation between average body weight and geographical area. People living in the core of Toronto, with mixed land uses and good access to public transport, have lower weights than those living in outer suburbs where car ownership and dependence are higher. The implication is that it is not just leisure-time activity that affects fitness, but transportation as part of everyday lives.