Almost one in four boys and more than one in five girls are overweight or obese at the start of their school life, figures showed today.
Another 35% of boys and 31% of girls in their last year of primary school (aged 10 and 11) also have weight problems, equating to almost one in three, the data for England revealed.
The figures have barely changed in the last few years, suggesting drives to cut childhood obesity have failed to have an impact.
Around 90% of all eligible children were weighed and measured in the 2008/09 school year as part of the Government's National Child Measurement Programme.
This equates to more than a million children in reception year (aged four and five) and Year 6 (aged 10 and 11).
Of those, 115,319 in reception year were found to be overweight or obese along with 162,408 in Year 6.
In reception year, 24% of boys were overweight or obese (14% overweight, 10% obese), while 22% of girls were overweight or obese (13% overweight, 9% obese).
In Year 6, just over 14% of boys were overweight and 20% were obese, while 14% of girls were overweight and 17% were obese.
Obesity was much higher than the national average in London, the north east and the West Midlands.
The report revealed that the percentage of obese children in Year 6 (18.3%) was almost double that in reception year (9.6%).
Meanwhile, the percentage of overweight children was higher in Year 6 (14.3%) than in reception year (13.2%), according to the study from The NHS Information Centre.
Its chief executive, Tim Straughan, said: "This is the fourth year of the programme and participation in the study has grown to more than a million children.
"The study shows that the number of children starting their school life either overweight or obese is just over one in five and that it is even higher in Year 6 where nearly one in three pupils is either overweight or obese.
"These findings echo very closely the picture that emerged from last year's study.
"They highlight the scale of obesity among some of our young children - something which may affect their future health."
Tam Fry, board member of the National Obesity Forum, said: "The levelling off of the figures is good news but one swallow does not make a summer.
"We are going to have to have two or three more years of this kind of result before we can say obesity is levelling off for good.
"Then, of course, you've got the problem of lowering obesity rates, which is what we should be aiming for.
"It's only when we see rates falling that we can break open the champagne.
"There is no cause for complacency whatsoever."
Mr Fry said the Government's Change4Life programme and its Start4Life component needed to start having an effect.
"If Start4Life simply rests on leaflets and posters, it is doomed from the start.
"We need more people on the ground to advise parents of pre-school children on preventing them becoming obese.
"We've got to invest in people - midwives, school nurses and health visitors - and put them back into the system.
"The Chancellor should also have been looking at a tax on unhealthy foods like fizzy drinks, which are linked to obesity and tooth decay.
"It would have been salient to tax fizzy drinks as a reminder that you consume them at your peril."
Harry MacMillan, chief executive of Mend (Mind, Exercise, Nutrition, Do it), which has received Government money to run weight-loss programmes, criticised the way strategies were co-ordinated nationally.
He said: "There is a shortage of money reaching the frontline.
"The Department of Health has given about £65 million to primary care trusts (PCTs) to help them combat obesity, primarily focusing on children to date.
"We know from our estimates that only a maximum of £10 million is reaching the frontline - reaching child weight management programmes.
"We train staff to run their own programmes and provide the kit they need.
"In January, there will be just under 400 programmes around the UK.
"I would say a good number of these are oversubscribed but some of them have space.
"The co-ordination of programmes by PCTs is piecemeal around the country and that's not very efficient.
"We're not saying Mend should be given all the money, but we're a fan of doing things efficiently.
"We've got a proposal in that you could get things for half of that £65 million.
"By spending less than £30 million and doing things in a co-ordinated way, we believe we could impact 400,000 children and their parents in three years, and have a wider impact on 2.5 million people."
Public Health Minister Gillian Merron said: "Evidence is stacking up to show that child obesity is levelling off.
"This is thanks to the hard work of families, schools and the NHS across England, supported by Government initiatives such as Change4Life and Healthy Schools, and action from industry and local communities.
"It's important to monitor children's weight and well-being, and I'm glad that we achieved a 90% take-up of the scheme.
"But we need to keep the momentum going. We'll only turn the tide on obesity for good if everyone plays their part."
Ann Stubbs, a single mother from Walsall, was one of thousands of parents who received a letter about her child's weight.
She said: "Receiving the letter was a real wake-up call.
"I haven't made a big deal out of it, but we have now signed up to Change4Life and, as a family, we are now trying to take more exercise together.
"We go walking, swimming and bike riding and I am not buying chocolate any more.
"The kids have a choice of fruit and yoghurt for dessert and fruit for snacks."Reuse content