Child obesity levels have been rising for decades
More than one in five children in England start their school life overweight or obese, NHS figures show.
What is more, by the end of primary school the rate rises to nearly one in three, the government's child measurement programme showed.
Obesity levels were higher in London, the North East and West Midlands than elsewhere in 2008-9.
But the NHS Information Centre said there were no significant changes in the results from last year.
NHS chiefs warned the true levels of obesity were likely to be a little higher as the parents of overweight children were more likely to opt out of the voluntary programme.
In total, more than 1m children took part, 90% of the age groups.
It comes after figures released earlier this year suggested childhood obesity may be levelling off.
However, the data on which that was based comes from a different source which has figures going much further back than the child measurement programme.
The schools data showed more boys than girls were overweight in both reception and year six.
Some 24% of boys aged four to five were overweight or obese, while 21.5% of girls were.
In the 10 to 11-year-old age group, 34.5% of boys and 30.7% of girls weighed too much.
NHS Information Centre chief executive Tim Straughan said: "These findings highlight the scale of obesity among some of our young children - something which may affect their future health."
Public health minister, Gillian Merron, said evidence is stacking up to suggest that child obesity is "levelling off".
"It's important to monitor children's weight and wellbeing, 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."