The World Health Organization says more than 1 billion adults are overweight and 300 million of them are obese, putting them at much higher risk of diabetes, heart problems, high blood pressure, stroke and some forms of cancer.

Zimmet, a diabetes expert at Australia's Monash University, said there are now more overweight people in the world than the undernourished, who number about 600 million.

People in wealthy countries lead in overeating and not doing enough physical activity, but those in the poorer nations of Asia, Africa and Latin America are quickly learning bad habits, experts said.

Thailand's Public Health Ministry, for instance, announced Sunday that nearly one in three Thais over age 35 is at risk of obesity-related diseases.

"We are not dealing with a scientific or medical problem. We're dealing with an enormous economic problem that, it is already accepted, is going to overwhelm every medical system in the world," said Dr. Philip James, the British chairman of the International Obesity Task Force.

The task force is a section of the International Association for the Study of Obesity, a professional organization of scientists and health workers in some 50 countries that deal with the issue.

James said the cost of treating obesity-related health problems was immeasurable on a global scale, but the group estimated it at billions of dollars a year in countries such as Australia, Britain and the United States.

Among the most worrying problems are skyrocketing rates of obesity among children, which make them much more prone to chronic diseases as they grow older and could shave years off their lives, experts said.

The children in this generation may be the first in history to die before their parents because of health problems related to weight, Kate Steinbeck, an expert in children's health at Sydney's Royal Prince Alfred Hospital, said in a statement.

Experts at the conference said governments should impose bans on junk food advertising aimed directly at children, although they acknowledged such restrictions were unlikely to come about soon because the food industry would lobby hard against them.

"There is going to be a political bun fight over this for some time, but of course we shouldn't advertise junk food to children that makes them fat," said Dr. Boyd Swinburn, a member of the International Obesity Task Force.

Dr. Claude Bouchard, president of the International Association for the Study of Obesity, an umbrella group for medical organizations dealing with weight-related and children's health issues, said the group supported advertising bans as official policy.

But the policy position is unlikely to have any immediate effect on influencing governments to introduce such bans, said Bouchard, head of the Pennington Research Center at Louisiana State University at Baton Rouge.

"Children are sensitive at an increasingly early age to their physical appearance," said Leeds University professor Andrew Hill.

"The impact of being overweight on girls' self-confidence has been detected in children as young as five years.

"Psychological factors such as perceptions of one's attractiveness, physical ability and self-esteem can be improved with even a modest weight loss," he told more than 2,000 delegates to the congress, which is held every four years.

Adult women were also affected psychologically by being overweight, said Deakin University researcher Kylie Ball.

New findings from a major study of women's health in Australia showed that physical inactivity and high body weight in adults were independent predictors of depressive symptoms three years later.

"In other words, the study showed that women who were overweight or obese -- regardless of how much activity they did -- were at increased risk of depressive symptoms three years on," Ball said.

"Women who were physically inactive also had an increased risk of depressive symptoms when surveyed three years later."

The Women's Health Australia project had also shown that obesity may have lasting effects on young women's life satisfaction.

Obese women were less likely to aspire to higher education and were more dissatisfied with work, relationships and social activities than women in a healthy weight range, the study of 7,800 women showed.

"These results have implications for the content of weight-loss programs," Ball said.

"There is a need to address the adverse psychological consequences of high weight gain and help people to be more accepting of their weight and themselves, while assisting them to achieve their goal weight."

The congress, which runs until Friday, is seeking practical methods of combatting what chairman Paul Zimmet called "this insidious, creeping pandemic of obesity now engulfing the entire world".

Obesity is the greatest single contributor to chronic disease and the world now has more fat people than hungry ones, according to World Health Organisation figures.

The strain was originally discovered by scientists earlier this year. They looked at cases of multiple drug-resistant TB - which has developed over the past decade in many parts of the world - and discovered that among these a worrying new 'extreme' strain had evolved.

'Mainstream drugs are ineffective against multiple drug-resistant TB,' said Nunn. 'However, there are half a dozen second-line medicines that can be used to tackle it. Now this new extreme resistant strain has appeared. It is not only resistant to our principal anti-TB drugs, but to many of our second-line defences. In short, we are now on the last line of our defences against tuberculosis.'

Among the areas found to have been affected by extreme drug-resistant TB are Latvia and South Africa. Scientists discovered the strain last month among HIV-infected patients in the Kwazulu-Natal region. 'Fifty two of the 53 infected people are already dead, and the last may well have died by now,' added Nunn.

An estimated 4.5 million people in South Africa have HIV. Extreme drug-resistance TB could devastate the population. 'If countries don't have the diagnostic capacity to find these patients, they will die without proper treatment,' said Nunn.

As a result, WHO is to hold its emergency meeting in Johannesburg to help establish measures that will lead to the rapid diagnosis of the new strain.

'It appears to kill within a few weeks and that does not give us a lot of time to spot it and treat it with the right drugs,' added Nunn. The few classes of drugs that are still effective against this strain of TB are expensive and can be toxic.

The meeting will be attended by officials from WHO and its partners, including the South African Medical Research Council and the US Centers for Disease Control and Prevention.

Five samples out of 27 tested positive for the unauthorized rice strain, officials at the two groups said.

"Innocent consumers again become the victims of the GE (genetic engineering) industry's 'contamination first' strategy," Greenpeace International GMO campaigner Jeremy Tager said in a statement.

The Chinese rice contained a protein that might cause allergenic reactions in humans, he said. It was supposed to be used only in field trials and was not approved for commercial growing because of concerns about its safety.

Dutch company Heuschen & Schrouff, one of the importers cited in the report, said it was investigating the case and would check with its suppliers.

"We have no comment. This information is very new to us, we received it just half an hour ago. We import the products so we are checking with our suppliers. Our quality department is also involved," commercial manager Bernard van Schaik told Reuters.

Heuschen & Schrouff Oriental Foods Trading BV says it is the market leading distributor of authentic Asian food and non-food in Germany, Austria, and the Benelux countries.

A spokesman for Seewoo Foods Ltd, Britain's largest supplier of Chinese foods which was also cited in the report, was not immediately available for comment.

The discovery of the experimental rice comes just a few weeks after the European Union tightened requirements on U.S. long-grain imports to prove the absence of another biotech rice type detected in samples intended for commercial use.

The EU does not yet permit the sale, import or marketing of any biotech rice on the territory of its 25 member countries.

European consumers are well known for their wariness over GMO foods, but the biotech industry says its products are perfectly safe and are no different to conventional foods.

"Once illegal GE crops are in the food chain, removing them takes enormous effort and cost. It is easier to prevent contamination in the first place," Tager said.

Last month the EU-25 tightened requirements on U.S. long-grain rice imports to prove the absence of the GMO strain LL Rice 601 marketed by Germany's Bayer AG and produced in the United States.

The EU decision followed the discovery by U.S. authorities of trace amounts of LL Rice 601, engineered to resist a herbicide, in long-grain samples targeted for commercial use.

Mr Kyprianou said: "The internal market applies to health services. People can shop around."

Opening the market could provide lucrative opportunities for private providers to lure clients from across Europe.

The move would have big budget implications for countries such as the UK, which effectively rations healthcare by limiting capacity and having long waiting lists. EU health spending rose from an average 7 per cent of gross domestic product to 7.7 per cent between 2000 and 2003.

On Tuesday Mr Kyprianou will launch a debate, requested by member states, in the European Commission that will lead to proposals within months for how the market should function.

"We need to give people information. For example, if you want a hip replacement, where do you go, which country? There must be a better way to help the citizen make a choice," he said. "On the other hand, can a receiving country turn down a patient?"

About 1 per cent of operations across the EU involve people from other countries. Defining "undue delay" will be one thorny issue. "I am not going to produce a list of time limits," Mr Kyprianou said. There is also the question of liability if an operation goes wrong and who should pay for follow-up treatment when the patient returns home.

Patients could only travel for treatment that would be available in their own country and at the same price. They would have to meet extra costs themselves.

Jim Murray, director of European consumer lobby group BEUC, welcomed the debate. "Patients need much more clarification of their rights," he said.

Although José Manuel Barroso, the liberal president of the European Commission, wants to go further. Many members insisted health be excluded from a recently-agreed EU directive to liberalise trade in services.