The war on drugs brought spiraling levels of addiction; the war on terror inflamed violence throughout the world. So here comes the war on fat.

Launching a $218 million program to test the health of Victorian workers, Premier John Brumby declared obesity a challenge “as big as climate change”.

Really? The Intergovernmental Panel on Climate Change says unchecked global warming will destroy up to 70 per cent of plant and animal life. How, exactly, are the poor fatties responsible for anything of that order? Are they supposed to be eating endangered species or something?

But you can make almost any absurd claim on this topic, since the ways we respond to obesity have very little to do with rationality.

Take a look at The Biggest Loser, the Abu Ghraib of the war on fat. No-one emerges any healthier from the show. In fact, the rapid weight loss of the contestants promotes the kind of fad diets and insane exercise regimes that every reputable nutritionist condemns as medically disastrous. But that doesn’t matter.

The Biggest Loser rates so well since it takes moral outcasts (ie. fat people) and makes them perform a very public penance. Each episode resolves in tears, as the heaving, sweating tubsters acknowledge once again how they were blind but now they can see – and henceforth they will worship at the treadmill and the calorie counter.

Yes, obesity is a problem, and fat people often have a miserable time. But the reasons are social much more than medical. The fatter society gets, the more desirable thinness becomes – making those extra pounds another factor in the quiet unhappiness of most people’s lives.

As for the medical consequences, it’s remarkable how rubbery the consensus actually is. Our sedentary lifestyles are dangerous – but it’s physical activity rather than weight loss that makes the most difference to your health.

Paul Campos, a war on fat dissident, explains:

[F]or most people, increased physical activity does not produce significant long-term weight loss. And people who lose a lot of weight don’t get any benefit over people who lose a little weight, so the benefit of weight loss by itself is medically nonexistent. But the good news is you don’t have to become thinner to enjoy significantly improved health.

Even with type 2 diabetes, lifestyle changes can make a difference, without a loss of weight. As the unfortunately-named Linda Bacon says, it’s preferable to talk about lifestyles rather than obesity, since there’s no actually no proven method for achieving long-term weight loss, and many of the common techniques are actually dangerous.

Yet for politicians – especially social democratic politicians – a declaration of war on fat is irresistible precisely because it shows them doing something, yet commits them to absolutely nothing. Will there be less obesity in the future? Fat chance!

Jeff Sparrow is the editor of Overland magazine.