Richard Hannaford, BBC Health Correspondent: "Nearly half of all men and a third of all women are overweight"

A task force from the British Nutrition Foundation has been examining the issues surrounding the seriously overweight for the last two years.

And they have come to the conclusion that the problem cannot be tackled simply by lecturing fat people to eat less and do more exercise.

The man chairing the task force, Professor John Garrow, told the BBC that health education needed to be focused on obesity, which is swiftly becoming one of the most significant causes of ill health in Britain.

He said: "Health education has consistently ignored the subject of obesity. They have got look after your heart programmes, but nothing for people who want to lose weight."

Noting the rise in the number of people having drastic hospital operations such as stomach stapling in a bid to lose weight, he said the NHS could save money if it organised its own slimming service.

He said: "At the moment it rests completely on the private sector to provide this. Some of these companies are good and some are bad."

British Nutrition Foundation's Sarah Schenker: Major increase in obesity in last 20 years

The latest figures show that one in five UK women, and only slightly fewer men are now clinically obese - almost half of all adult men, and a third of women, are classed as simply overweight.

The task force report said: "Action is needed now to prevent the spread of the problem to epidemic proportions."

The task force included experts in biochemistry, medicine, dietetics, exercise, genetics, health education, psychology and surgery.

It said a change in "national lifestyle" was needed to involve a higher level of physical activity, and a universal diet which includes more fruit and vegetables.

But in addition to this, the government must play its part, indirectly encouraging exercise by removing the barriers which discourage people from taking part.

Cycle lanes rather than lectures

Amanda Wynne, a nutrition scientist at the foundation, said: "Things that can be done might include setting up more cycle lanes so people feel safer riding bicycles, or dealing with crime and improving street lighting, which would encourage people to walk more.

"We have been saying to people: 'Go on a diet and take exercise' for years, and levels of obesity are still rising. We need new policies to promote physical activity and healthy eating.

"It's a global approach to obesity that is needed."

She said research had shown that obesity had risen despite an overall decrease in the daily energy intake of the average person.