The resolution will put doctors on a collision course with Coca-Cola and Pepsi, plus the likes of McDonald's and Burger King.

Sales of soft drinks in U.S. schools are in decline ahead of the introduction of guidelines allowing only healthier low-calorie drinks, plus milk and certain fruit juices, over the next two years.

But the medical association wants to go further. Delegates at its Chicago conference are gunning in particular for high fructose corn syrup, the sweetener which is added to everything from ketchup to cola.

One American politician labelled it the 'crack of sweeteners' because it is so widespread.

Some U.S. cities and states already levy taxes on soft drinks or junk foods that raise £500million a year, said Michael Jacobsen, director of the Centre for Science and the Public Interest, an independent health watchdog. But earmarking tax revenue for programmes promoting better diet would be a first, he added.

American doctors are seeing the same alarming trends as those in Britain where obesity is considered to be a 'ticking timebomb of epidemic proportions'.

More than 30,000 Britons die each year because of obesity. In England, 47 per cent of men and 33 per cent of women are overweight, with around a fifth being obese. The problem costs the Health Service £500million in consultations, drugs and other therapies.

Life insurance companies are considering increased premiums for overweight clients because so many are dying prematurely from heart disease and cancer. Cancer Research UK has warned that obesity will soon cause more cancers than smoking.

Just as alarming is the rapid growth in childhood obesity. Among six-year-olds, one in ten is classed as obese, rising to one in five among 15-year-olds.

The Government has warned that the current generation of schoolchildren could be the first to live shorter lives than their parents.

He said it was sad that Chile's conservative opposition is fighting a government which has worked out plans to punish inappropriate employment of laborers under 15, and to govern the working hours for older teens so that they can still study if they wish.

Guillermo Miranda, director for Latin American affairs of the International Labor Organization (ILO), praised the Chilean initiative, saying, "It is a goal that is within reach."

The ILO data showed that Chile has the lowest child labor rates on the Continent, with 196,000 working minors, of whom 107,000 working under unacceptable conditions.

Chile's National Minors Service has said 66 percent of working children are boys and 34 percent are girls, noting that 74.1 percent are aged between 15 and 18, of whom 55.7 percent do not attend school.

According to the same data, nearly 20 percent of Chile's working children are in some way involved in illegal activities, including sex work.

The study begins with some sobering observations about the record run in the US housing market. Over the past five years house prices have outstripped income growth more than sixfold - the median home now costs more than four times median household income in 49 out of 145 metropolitan areas in the US, a record. In 14 metropolitan areas, the median house is now worth more than six times median income. Last year saw the average house price shoot up 9.4 per cent - the biggest rise in the average house price since records started more than 40 years ago.

Financial strains on US home-owners have been mounting. The number of Americans devoting more than half of their incomes to housing climbed by 1.9m to 15.6m in the three years to 2004.

To bridge the gap between sluggish earnings growth and speedy house price growth, ever more Americans have been tempted by riskier flexible-rate mortgage products. More than a third of loans last year were at adjustable rates and may rebound on their holders if interest rates continue to climb. Even more reckless buyers, about 10 per cent last year, opted for payment-option mortgages - which do not require full payment of the interest costs.

So why will non-home-owners be deprived of the crash they have been waiting for?

The strongest underlying support for the market comes from accelerating household formation. Demand is being driven not only by population growth but by household fragmentation, as couples divorce or children leave home.

Immigration has been a still stronger force - over the past decade 12.6m new households were formed in the US. Over the next 10 years the pace of household formation will accelerate to 14.6m, according to the Joint Center for Housing Studies.

"Even if America decided to close the borders now, we would still see the lagged effects of previous waves of immigration," said Mr Retsinas. "Many of those that came to America earlier are only now in a position to buy property. As it is, we don't believe there will be any slowdown in immigration."

The Harvard study also argues that there are fewer points of vulnerability than during previous housing market downturns. The macroeconomic outlook for the US is uncertain but no mainstream economists are predicting the kind of surge in unemployment or leap in interest rates that would prick the housing bubble. In spite of the shift towards flexible rate mortgages, 75 per cent of mortgage holders have 30-year fixed rate loans and are therefore largely invulnerable to rising rates. A third of households own their homes outright.

Nor are manylikely to suffer from negative equity should rising interest rates or unemployment drive up defaults - about 94 per cent of home-owners have equity of more than 10 per cent.

Over-development has also been less of a problem than in the past, the study says. Price declines associated with episodes of big job losses alone average 4.5 per cent, while those occurring around periods of over-building alone average 8.3 per cent, it says.

Not everyone concurs, however. Many economists say national figures are deceptive, since they obscure pockets of extreme over-valuation in property prices and greater vulnerability to rising rates. Others point to evidence of overbuilding in recent years. Residential investment has risen to 6 per cent of gross domestic product - its highest level in 50 years and much higher than the average of 4.75 per cent.

The Harvard study concedes that even a slowing housing market could take a heavy toll on growth, as Americans become less able to use their houses as ATM machines and less employment is created by homebuilding. Provided the slowdown is gradual, as Harvard expects, this could help rebalance the US economy, reducing demand for imports and so stemming the growth of the trade deficit.

Half of that amount would be returned to the ministries concerned, he added after unveiling letters sent to each establishing spending ceilings contained in the 2007 budget, part of which is to be presented on Tuesday.

The spending limits were part of a move to modernise the state apparatus, the official said, adding: "It is a question of providing the same quality of service at a lower cost, the French will not feel the effects."

The French public deficit has repeatedly breached European Union limits and the EU Commission said early this month that it could happen again this year.

In economic forecasts unveiled on May 8, the commission voiced skepticism about France's commitments for reducing its chronic deficit.

"I would like the French government to take new measures without waiting for 2007" to bring the deficit into line, EU Monetary Affairs Commissioner Joaquin Almunia said at the time.

According to the plan presented on Monday, around 19,000 full-time posts are to be eliminated through natural attrition, and about 4,000 created among security forces and judicial services, and in research programs, parliament deputy Hervé Mariton told AFP.

The education ministry is to see a little more than 7,000 jobs cut, while the finance ministry is to lose a total of almost 3,000.

Around 4,400 cuts are slated at the defence ministry, though the national gendarmerie which is part of that ministry is to gain almost 1,400.

Meanwhile, government spending is to be kept to one percentage point below the level of inflation, which would be 0.8 percent at the present level of 1.8 percent.

"This is unprecedented in the history of French budgets," the ministry official said, while the government took pains to point out that programs proposed by the opposition Socialist party would increase the French debt.

Villepin's conservative government set a goal of bringing the public deficit to 2.5-2.6 percent of gross domestic product in 2007, and overall public debt to 64.6 percent of GDP at the end of this year.

Eurozone countries are supposed to maintain public deficits of no more than three percent of GDP and maximum overall debt of 60 percent.