Britain's obesity problem is exaggerated and children are being dubbed overweight when often it's nothing more than "puppy fat", Birmingham's head of education claimed.

Councillor Les Lawrence said Britain was at risk of stigmatising youngsters and opening them up to bullying amid the obsession on weight.

He claimed health experts and Government Ministers were exporting an American problem to the UK without properly examining the real situation over here.

His comments come amid increased concern over weight in this country.

The Government's Chief Medical Officer, Sir Liam Donaldson, has warned of an "obesity timebomb". Research says six out of ten people will be obese by 2050 and nearly one in five children aged two to 15 already are.

Launching a range of initiatives to tackle obesity last week, Health Secretary Alan Johnson described it as "the most significant public and personal health challenge facing our society".

However, Coun Lawrence (Con Northfield), Birmingham's Cabinet Member for Children, Young People and Families, said: "There is no doubt America does have an obesity problem. But I think some how we have transferred that obesity problem from there to here without really looking at it.

"Improvements in lifestyle mean that both in terms of height and skeletal frames we are bigger than our parents and grandparents. How we interpret things like body mass weight I don't think has moved on in terms of the human frame."

Ministers last week ordered cookery lessons to be made compulsory for secondary pupils as a key part of a £372 million strategy to cut obesity.

However, Coun Lawrence criticised linking the two things.

He said: "Youngsters should be taught the basics of cooking because it helps with independent living and moving away from purely processed food.

"That should be the focus, not overlyconcentrating on obesity as the driver of this initiative. I don't think the problem is as big as is being made out."

Coun Lawrence claimed "over-exaggeration" of the problem was creating an "an atmosphere of fear" which meant youngsters who appeared overweight were targeted by bullies. "When you look at the life cycle, particularly between 0 and 14, some children have characteristics that maybe classed as obese but as they develop it disappears," he said..

"It might just be puppy fat."

Sir Liam, however, last night reiterated Government concerns.

"In England alone, nearly a quarter of men and women are now obese," he said.

"The trends for children are even more a cause for concern, with 18 per cent of two to 15 year olds currently obese and a further 14 per cent overweight." He added that two out of three children are predicted to be obese within 30 years.

"If this trend continues, millions of adults and children will inevitably face deteriorating health and a lower quality of life and we face spiralling health and social care costs." he said.

Birmingham City Council's lead officer on children's nutrition and health Dr Patrick Lowe also stressed the extent of the problem.

"The last figures we had for 2005/06 revealed that 20 per cent of reception children in Birmingham, those aged four and five, were obese and that did not include those children who were overweight," he said.

"We are due to publish new figures in March, but I can tell you that the problem has got worse, markedly so." A cross-Government health strategy to tackle obesity aims to fundamentally change people's eating habits and encourage healthier lifestyles. As well as including compulsory cookery classes for 14 to 19 year-olds, teachers are urged to clampdown on the contents of packed lunches and employers are being encouraged to introduce cash incentives to encourage weight loss.