Willpower or nannying is hopeless, but a dose of team spirit might shed the UK's extra kilos.

Phewee. I am feeling a bit wrung out because I have just got back from the battlefield - I mean the zone of moral conflict that I now enter every time I open the door of the fridge. The plan was to have an apple, and then I thought it might be nice to have something to go with the fruit; something sharp, savory - and before I could help myself I had wrenched open that Pandora's box and stood bathed in its lurid glow.

There it was, the thing that had been calling to my subconscious. It was the cheese: curvaceous, enticing, gorgeously perfumed. It seemed to be winking at me on the ledge, in a provocative way. Go on, said the great moldering lump of ancient cheddar; you know you want it, don't you?

As we stared at each other I felt the willpower start to drain invisibly through the soles of my shoes. The sweat formed on my palms; up and down went my gulping Adam's apple. I gazed at that full-fat, extra-mature, golden-skinned ingot of dairy-based destruction with the hopeless lust of the hobbit as he gazes at the Ring of Power, or a bishop unexpectedly opening the door of a brothel.

Failing willpower

With a gasp I tore my eyes away. I slammed the door shut, and having eaten that apple in two ravening bites I am here to tell you that this time it is different. This time I have found an entirely new way of losing weight, and on this occasion I am not relying on conventional dieting willpower; or to be more precise, I am not relying solely on my ability to act rationally in my own self-interest. From now on, folks, it is not just about me. It is about us.

Let me explain. It must be 20 years ago that I first wrote a piece about what was already being called a "national obesity epidemic". My thesis was one of pure and pitiless libertarianism. I scoffed at the notion that our collective fatness was somehow a problem of government.

If people were too fat, I said, then that was because they were too darn greedy; and if they wanted to get thinner then they should eat less. Simple, I said. The more we "medicalized" the problem, the less people would take responsibility - and the fatter we would all become.

Well, I am afraid that in the past two button-busting decades, I have been proved right at least about the last point. The UK is now the second-fattest nation in the world, and I am alarmed to discover that Londoners are now even fatter than New Yorkers. We have obesity levels of 67 percent among men and 57 percent among women. We are the official fatties of Europe.

Fat troops

Every year we have to widen our cinema seats and reinforce the floors of our ambulances. As reported recently, an increasing number of British soldiers are made to leave the army for being, frankly, too fat to charge at the enemy. Our charter jets puff and groan and spew out unconscionable quantities of fossil fuels as they lug our biomass to the Mediterranean - and the fatter we get, the greater the risk to our health. The more overweight we are, the more likely we are to have cancer, heart disease, stroke: the big causers of early and preventable death. The national fatness problem costs the National Health Service at least 16 billion pounds ($27 billion) a year in extra and unnecessary expense.

Nothing seems to stop us eating too much - neither my savage libertarian sermons in the Telegraph, nor the bossing and nannying of the state. We are akratic. We know what we should do, but we can't seem to make ourselves do it. We know what is in our interest - cut out french fries, cake, bread, cheese, chips, etc, and eat more fruit - but we can't summon up the consistent willpower to follow the rules.

Brooding on this problem, I wondered if we could construct a different psychological framework. What if it wasn't just about us: our selfishness, our weakness of will, our own abusive relationships with food. Perhaps people might be more willing to exercise discipline - to make a sacrifice - if it could be seen to be for everybody's sake, for everybody's health.

People are generally capable of amazing acts of kindness and altruism. Seldom are people happier and more energetic than when doing things for others.

City Hall initiative

So at City Hall we have all embarked - about 150 of us, I think - on a plan to lose weight together.

We all stood on some giant commercial scales; not individually, so that no one felt any personal embarrassment or pressure, and we didn't have the anxiety of other people seeing how much we weighed. We did it in groups of about 12 at a time. We recorded who was in the groups, and the total weight, and we agreed that in a few months we would try to lose 5 percent.

There is no coercion, no bullying, and it goes without saying that the whole thing is entirely voluntary. It is a joint effort and a bit of a laugh. But the key thing is that I now know that unless I keep it up - and refuse the lascivious winks of the cheese and the cake - then I will not just be failing to do the right thing by myself. I will be failing to do the right thing by the group.

I need to lose weight or I'll let the side down. In a few months' time we will all get back on the scales and see how we have done. Will it work? Every psychological textbook will probably say that you only get results by appealing to people's naked self-interest. Well, we have tried that, and it's going nowhere. Let's try team spirit. It's worth a shot.

(China Daily 08/02/2014 page23)