Janet Street-Porter: Forget the perfect diet, just eat less

Scientists in Australia claim that they've come up with a diet which is guaranteed to work - and the moment they published their findings in a book entitled The Total Wellbeing Diet it went straight to the top of the bestseller lists there, proving more popular than Harry Potter and The Da Vinci Code. It has just been published here, and you can download a week's worth of recipes and meal plans for free via the internet.

The Commonwealth Scientific and Industrial Research Organisation (CSIRO) is an extremely respected institute, and its unit in Adelaide is renowned for its pioneering work into genetic and nutritional factors affecting obesity, heart disease, bowel cancer and diabetes. Concerned by all the conflicting advice offered to the public from competing diet "gurus", they decided to take the radical step of publishing their work in a paperback. They found, after constructing eating plans for 120 obese women, that a high-protein, low fat diet led to 25 per cent more weight loss over a 12-week period than a diet loaded in favour of carbohydrates but low in fat.

At any one moment, we in the wealthy industrialised world can be sure that at least half a dozen of our acquaintances will be eating according to a specified regime in the hope of losing weight. I have friends who are on the Atkins diet, the blood group diet, the food-combining diet and the carbohydrate diet. Then there's Weight Watchers (led by a former member of our Royal Family), not to mention the Dine Out and Lose Weight regime.

At the same time as the book lists are crammed with diet books - and I fully expect that The Total Wellbeing Diet will be a bestseller in this country, and eventually in America - we find nothing bizarre in the fact that we over-eat so much that we feel the need to buy loads of advice about how to lose weight. At the same time, we dig deep into our pockets to send money to charities working to eliminate hunger and poverty in the Third World.

Every week, each household in Britain probably throws away more food than most African families would eat in a month. And to accommodate our growing girth, clothing manufacturers have revised what constitutes a size 12 or 14, making them larger than before so we don't feel too distressed by our ever-expanding waistlines. Try on a T-shirt called medium in the United States and you find it is the size of a small bungalow.

Food is the biggest addiction facing the West, more than drugs or drink. Having just spent a week in Michigan, USA, I can tell you that even with Morgan Spurlock's Super Size Me (with his dire warning about the perils of fast food) a national hit, the amount of food placed on your plate at every meal in a restaurant is grotesque. America has become the country where the poor are fat and the very rich can afford to be thin.

The same thing is happening here, but for the moment, most of Britain, right through all the social classes, is several kilos heavier than it needs to be. At the same time, the middle classes are fed a huge amount of information about food every day, via restaurant reviews, cookery pages in the press, and whole magazines devoted to the subject.

We can work out where to buy food that is totally politically correct, from eggs from happy free-range hens to organic meat and vegetables. We can support local farmers and demonise supermarkets who fly in vegetables from other continents. We can eat according to the season or our star sign, and one of Britain's most respected food writers, Nigel Slater, has just published a book about what he cooked and ate for a year. It will be required bedside reading for middle-class women throughout the land by the end of the month.

What I find so depressing about the so-called perfect diet, is that it reads just like every other diet, with its emphasis on low-fat spreads, sliced bananas, wholegrain bread and 200 grams of fish or lean meat, controlled alcohol intake and celery sticks. For every person who sheds 25 pounds on this diet, there will be another weak-willed sucker who weighs even more a year later.

Simple, proved single fact: you want to lose weight, try eating and drinking less. But the whole concept of less is a non-starter. We are better at the notion of going without than the more difficult process of cutting down. That's why rehab is such a popular concept - it takes four to eight weeks, and afterwards you have eliminated something from your life forever, be it drink or drugs. Saying no is easier, and far more fashionable, than saying I'd like just a little.

At a time when one in four girls and one in five boys are overweight, the Government is right to focus on what children eat. No one would accuse Ruth Kelly or her department of acting like interfering nannies, after seeing Jamie Oliver's television series about the appalling standard of school food.

Miss Kelly's committee has produced some really sensible conclusions, from banning vending machines that sell junk food right through to setting out nutritional guidelines for lunches. They are in agreement with Mr Oliver's conclusion that, left to their own devices, most kids would just eat fattening junk.

Now schools will have to provide hot food using ingredients from local suppliers, cooked on-site. This will involve rebuilding one in eight kitchens from scratch, and doubling the current spending on school food. By 2011, children may be restricted in what they can bring to school in packed lunches, and cooking lessons could be compulsory for children aged 11 to 14.

As one small boy has just died from an E.coli bug thought to have originated at a cooked meat company who supplied local schools, these guidelines cannot come soon enough. If the Government has to double what it spends on school meals, then surely parents will be more than happy to pay more.

I just can't understand two things. First, why are children allowed to bring packed lunches in the first place? There is provision for free meals for poorer families anyway, and those on special diets can easily be accommodated within the new guidelines. Parents can't cook, and are as fat as their children, so letting mum pack your lunch is no guarantee of anything more healthy than what the school will provide.

Secondly, why start teaching about food at the age of 11, when food fads are firmly entrenched? It should be easy enough to get kids interested in nutrition as part of their science classes from the age of seven, and they can certainly learn to cook simple meals. By the time they reach secondary school it's too late.