Health Survey for England data indicates that 62% of men and 53% of women are overweight, and 20% of women and 17% of men are obese.

This compares with 1980 figures which showed that just eight per cent of women and six per cent of men were clinically obese.

However, a report launched on Monday by the Bread for Life campaign has found that only three per cent of men and six per cent of women perceive themselves as very overweight.

More than half of all adults (57%) did not believe that they are at risk of being overweight in the future.

The campaign organisers believe that personal denial, coupled with confusion about what puts individuals at risk of obesity - particularly dietary factors - could be contributing to the escalating obesity levels in the UK.

Obesity is associated with increased risk of premature death and ill health.

It is estimated that obesity accounts for six to eight per cent of the total health care budget. After smoking, it is the most preventable cause of ill health in the UK.

Expert report

To address the problem, the Bread for Life campaign commissioned Dr Susan Jebb, head of nutrition and health at the Medical Research Council Human Nutrition Research Centre in Cambridge, to identify risk factors for individuals and to draw up strategies to combat obesity.

The risk factors identified by Dr Jebb in her report, The Weight of the Nation: Obesity in the UK, include:

• A high fat diet
• Low levels of physical activity
• Parental obesity

Dr Jebb warns that if the current trends continue, more than 25% of British adults will be obese by 2010.

Dr Jebb said: "Key to tackling obesity is helping individuals ahcieve a balance between the calories they consume in food and those they burn off in physical activity.

"Consuming a diet with less fat and a greater emphasis on carbohydrates, especially complex carbohydrates, such as bread, is a proven strategy for weight control.

"Complex carbohydrates can help curb appetite and subsequent snacking by makng you feel full."

Dr Jebb's report highlights a study that showed that people who ate a high level of fat in their diet were 19-times more likely to be obese than a group which had a low fat diet.

John Murray, executive director of the Bread for Life campaign, said research showed that many people were not clear about the role of complex carbohydrates in the diet.

"Fifty-nine percent of people mistakenly think bread is fattening when in fact, bread is part of the solution and not the problem," he said.