The scale of childhood obesity has been exaggerated, researchers have claimed.
The report suggests the rate of obesity among children has remained relatively stable
The Social Issues Research Council, which is funded by food companies as well as the government, said average child weights have only risen slightly.
SIRC, which compared average weights in 1995 and 2003, said obesity levels have started to rise among older teenagers but the middle-aged were most at risk.
However, the National Obesity Forum insisted childhood obesity was increasing and had to be addressed.
The team from the SIRC analysed data from the 2003 Health Survey for England.
It looked at children's average weights.
The survey showed that an average 15-year-old boy weighed 9st 7lbs (60.7kg) in 2003, compared with just over 9st 3lbs (58.8kg) in 1995.
For a 15-year-old girl, the average 2003 weight was slightly under at 9st 4lbs (58.9kg) compared with 9st 2lbs (58.5kg) in 1995.
The SIRC's report says: "We can conclude from these figures that there have been no significant changes in the average weights of children over nearly a decade.
"This can be taken as evidence that there has been no 'epidemic' of weight gain, since an epidemic would certainly have affected average weights."
SIRC also challenge the way the extent of childhood obesity is estimated in the UK.
Children are classed as obese if they fall into the top 5% in relation to the weight range for their age.
However, there is an international measurement which looks at height/weight distribution across six countries including the UK.
The UK method suggests obesity rates in children aged two to 10 have increased from 9.6% in 1995 to 15.5% in 2003.
SIRC said the international measure - which it said was better because it took into account the increase in children's average height since 1995 - showed rates had increased from 3.9% in 1995 to 6.75% in 2003.
Dr Peter Marsh, co-director of SIRC, said: "No one's suggesting there isn't a problem - clearly there are some children who are too fat for their own good.
"But there has been very little change over the last decade, contrary to the lurid warnings that the current generation of children will die before their parents."
Dr Marsh said people's weight tended to increase after they left school: "Then people take even less exercise and start to adopt lifestyles that lead to that kind of weight gain."
And he said people who were middle-aged or older were at highest risk of obesity and weight-related diseases such as Type 2 diabetes.
But obesity experts said it was important to instil healthy eating habits from a young age.
Professor Mike Kelly, from the Health Development Agency, said an increase in childhood obesity rates had been seen over the last 20 to 25 years.
But he said: "The real problem is not childhood obesity - we shouldn't get too hung up on that.
"The unfortunate thing is that patterns of eating, exercise and so on are set in childhood and that's why the emphasis has been on children."
Dr Ian Campbell, president of the National Obesity Forum, which receives some of its funding from drug companies, said: "The inescapable fact is that obesity among children is a real problem. The problem can't be over-exaggerated or over-stated."
A Department of Health spokeswoman said it used both the UK and international methods of assessing obesity rates because it was understood there were different ways of measuring the extent of the problem.
But she said: "What they both show is that there has been a rise."
She added: "It is essential that we tackle the proven year on year rise in obesity amongst children under 11 if we are to prevent our future generations becoming clinically obese - resulting in the threat of killer diseases like cardiovascular disease, type II diabetes and cancer."