Why did he have to bring it up? That's the question I keep asking about John Prescott, since, try as I might, I can't erase from my inner eye that image of the former Deputy Prime Minister glugging Carnation milk from the can or grimly chomping through his second packet of McVitie's digestives. And the bad pun is intended. Why did he make himself vomit afterwards and why did he feel the need to tell us?

Many find it grotesquely comic; a few believe his admission “brave”. But putting both aside, Mr Prescott's biography reveals a vivid portrait of the stress attendant on high office. A 16-hour-a-day gerbil wheel of redrafting some government pamphlet, isolated from his family in Hull and, one suspects, more than averagely racked by the inner dread that afflicts us all of being found out, Mr Prescott crammed his face with “any old rubbish”.

Burgers or M&S trifles: the food he ate, the taste, didn't matter. The pleasure, the lever that somehow released his internal pressure valve, was in “stuffing my face and feeling really full”. He would sneak off to the loo to purge so “I could carry on eating, do the same the next day”. The items consumed were irrelevant, quickly discarded, heaved into the parliamentary plumbing. What mattered, what he needed, was the process: consumption itself. And it struck me that this affliction is not confined to poor old Prezza, but that Britain has the same disorder: that our society is bulimic.

Mega-inflation in the price of staple foods - maize, rice and wheat - will be felt as a global wave, we are told. From Haiti to Bangladesh to the bacon counter in Tesco, customers will be shaking heads at prices. Except that while families in the developing world are already giving up healthcare or taking children out of school or cutting back on vegetables to pay for rice, in Britain we still throw away a third of all the food we buy.

Contemplating dinner yesterday, I looked into a half-empty fridge and was about to head down to Sainsbury when I realised I had enough for days. It wasn't that I craved roast chicken or a nice steak or anything else we lacked. I just wanted to shop, to browse and buy. And then enjoy the pleasure of filling my shelves, perhaps discarding the two sausages and slightly manky mushrooms I was tired of looking at, to make way for the new, interesting foods with all their unexplored menu possibilities.

Just how decadent is a society that can purge itself of decent food? The estimated £800 rise in a family's annual grocery bill could be more than absorbed by eliminating waste and reviving respect for food, eroded by decades of cheap produce. But then our bulimic society does not value any commodity for long. It's striking that while drug addicts or alcholics are viewed with severity, the term “shopaholic” is a joke. It is a giddy, girly-pink, frivolous name for the kind of idiot women, spurred on by fashion-magazine “must have” diktats, who “can't resist” a pair of shoes, or bags. It is fine, even encouraged, for a shopaholic to hide her habit; conceal her purchases, rip up receipts and lie to husbands - the fun-suckers - about her egregious debts.

Not that shopaholics I've come across garner much pleasure from what they buy. Unopened bags clutter up wardrobes, that sparkly top - one of three similar because, at Primark prices, why not buy every colour - is worn twice before ending in a bin bag in the back room. One former colleague would spend most lunchtimes in Oxford Street, arrive back flush-faced with a dozen frocks and tops, then the next afternoon return most of them for refunds. Her credit card, like Prezza's belly, swelled briefly to capacity, before the purge allowed her to trawl Selfridges, hungry once more.

At least this woman was only wasting her life. With personal debt rising to epidemic levels and the demise of cheap credit, surely the Government should warn us of the dire consequences of spending so far beyond our means. But shopaholics are the Gurkhas of the economy, bravely forging onwards through the high street while weaker, fearful consumers retrench. Their country needs them.

And, especially among the young, there is no shame in overspending: a fifth of 18 to 34-year-olds, according to a Mintel survey, see no stigma, should their financial pressures build to bursting point, in declaring themselves bankrupt and thus disgorging all their debts.

Globalisation has become a glib, catch-all phrase to explain why your favourite café was swallowed by Starbucks. But the world food shortage illustrates its true meaning: that our lives and our consumer choices are finely connected with those of the rest of the planet. I remember reading about biofuels a while back with bemusement. What, you fuel a car with corn? Wouldn't that take an awful lot of corn? Isn't it as daft as feeding, say, strawberries to a pig?

I assumed that far cleverer brains than my own - really worthy eco-minds - had figured this all out. (After all, I find most supposed solutions to global warming incomprehensible: how does donating money make a multinational company “carbon neutral”, how can I “offset” my flight to Australia by planting a tree?) But now when we drink more expensive beer - land that once grew hops having been turned over to ethanol-producing corn - we have some distant connection with Asia's empty rice bowls. Maybe we will realise the insanity of pretending we are saving the planet by pumping the West's SUVs with the hungry's cereal crop. Maybe we'll realise that the only solution is to consume less.

And when I hear teenagers contemptuous of a model of mobile phone because it's six months old, or when a young woman with a good job tells me she has 50 pairs of shoes, £6,000 on her cards, but thinks she'll never own her own home, I wonder if this is a bad thing.

John Prescott spilt his guts in his memoirs because, whatever the loss of dignity, however much this revelation will overshadow his whole political career, it will sell. And we will buy it because so many of us struggle with one appetite or another. We comfort eat, comfort shop, binge and purge.

Maybe a recession will hurt, but it might better align our wants with our needs. Like John Prescott in Mr Chu's of Hull, we aren't any happier eating the whole menu.

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