I know people who have the option of driving but instead take the train so they can improve their physical fitness. It takes longer than driving, but since they’re going to work anyway, walking to the station is an easy way to exercise. It makes good sense; I’ve walked or cycled to work at various times for the same reason.

However it’s one thing to make a private choice to use public transport in order to exercise – it’s another thing altogether to elevate the war on obesity and other health issues, as a matter of public policy, to the status of a key goal of the transport system. That’s what organisations like the Planning Institute and the National Transport Commission propose, but it’s not self-evident to me that it’s a good idea. It’s worth thinking about it further.

There’s a paradox here. The very point of public transport is to extend personal mobility. At the end of the nineteenth century when everyone other than the very wealthy walked, the arrival of trams and trains greatly enriched people’s lives by overcoming the limitations of walking. Now they could travel further to better jobs or better houses, take the family to the beach on Sunday, or visit friends and relatives in more distant suburbs. The whole point of public transport was to travel faster than walking so people could travel further in the same time.

The panoply of exercise-related issues like obesity are not a transport problem, they’re a social problem. They’re a result of eating more and of expending less effort in all aspects of life, not just in the way we travel. It’s true we are much more likely today to drive than walk, cycle or use public transport, but the avoidance of effort is true of almost everything we do.

Most of us work in jobs that don’t involve anything even remotely like the level of physical effort expended by the average worker of a few generations ago. If we did, Occ Health and Safety would have a fit. On the home front, we’ve had “labour saving” devices like refrigerators, stoves, washing machines and vacuum cleaners for generations. Television and home delivered newspapers mean we don’t even need to go out to get information and entertainment.

Consider the giant strides we’ve made in avoiding exertion over the last twenty years. Computers have eliminated the effort of going to the bank, the booking office, the travel agent or the bookshop. We blow leaves rather than rake them, we use power tools to drive nails and screws, we answer the phone without getting out of our seat, and we cook meals without having to prepare them. We control our air conditioners, central heating, TVs and sound systems with remotes. Climate control means our bodies don’t even consume much energy to keep warm – many children barely know what it means to shiver.

The decline of effort pervades all aspects of our lives, not just how we travel. For better or worse, it’s one of the ways we define progress. So transport – and that essentially means the car – is only one part of the health problem.

And in fact it’s a relatively small part, because the main cause of obesity is what we eat, not how little we exercise. It’s likely to be far more effective to target food than public transport.

Lennert Veerman, Senior Research Fellow at Queensland University’s School of Population Health, points to a recent study which argues the main force driving the obesity pandemic is an increase in consumption. He says the 1970s was:

When the food supply started to change radically. The supply of refined carbohydrates and fat increased and more food was mass prepared rather than cooked at home. The era of easily available, cheap, tasty, highly promoted, energy-dense foods had begun. This view of the causes of the rise in obesity prevalence suggests the likely solutions lie in the area of the supply and promotion of food. And research supports that notion.

He says if governments are serious about tackling obesity their priority should be food. They should tax unhealthy food, limit advertising and restrict availability in schools. He also says healthy food should be subsidised.

I think it’s always risky to extend the core purpose of an undertaking to include secondary objectives, particularly when the organisation concerned is in or close to the public sector. There’s always the possibility the core purpose might be compromised by ‘goal succession’. In some circumstances that might be a risk worth taking but in this case the argument for exercise seems pretty shaky to begin with.

I might be cynical but I can imagine scarce funds being diverted to transit services that are doubtful on mobility criteria but get over the line because of their claimed health benefits (or vice versa!). Perhaps one day a marginal service will be abolished with the excuse that another is a short health-enhancing walk away.

There’s also a paternalistic aspect to the “transport as exercise” meme that I think could rankle many travellers. We already know the great majority of travellers prefer a fast drive to a slower public transport journey so they can decide for themselves how to use their time. Telling people they should use public transport because it’s good for them might not be popular with those who see themselves as time-short.

I see no problem with public transport being promoted to users as an exercise choice (although I think it would be better if it were in the context of a wider “get active” message that looks at all aspects of day-to-day life). However I don’t think making obesity prevention an explicit and formal objective of transport policy is either a necessary idea or a good idea. Better to “stick to the knitting” and focus on the core purpose of providing mobility.

What’s more intuitively appealing to me is the converse – accessibility to health services (including preventative ones) should be a key objective of health policy. Hopefully the current Parliamentary inquiry into environmental design and public health in Victoria has an open mind.