A fifth of 10 to 11-year-olds in Woking are obese or severely obese, new figures show.
The professor in charge of children's health in England called obesity a "ticking time bomb", but warned the NHS cannot solve the problem alone.
New figures from the Office for Health Improvement and Disparities show there were around 175 obese or severely obese year 6 children in Woking in the last academic year, accounting for 18.2% of the whole cohort.
This was up from a year earlier, when 16.3% of year 6 children were obese.
Across England, 22.1% of year 6 children were obese last year – down from 22.7% in 2022-23.
Despite the recent improvement in childhood obesity, the national rate remains higher than before the pandemic.
In 2020-21, 25.5% of children were classed as obese, up sharply from 21% in 2019-20.
The data is from the Government’s national child measurement programme, which covers mainstream state-maintained schools in England.
The figures also show persistent inequalities exist, with children from the most deprived areas twice as likely to be living with obesity than those from the least deprived areas.
The Local Government Association said cash raised from the soft drinks sugar tax should be targeted at areas with higher levels of deprivation, child obesity and tooth decay.
It said the tax has raised £1.9 billion since it was introduced in 2018, "yet councils are increasingly concerned about where the money is being spent".
It also wants the tax extended to include milk-based drinks, such as milkshakes, high-sugar coffees, and other high-sugar items like cakes, biscuits and chocolate.
Dr Helen Stewart, officer for health improvement at the Royal College of Paediatrics and Child Health, said the inequality across the country was "impossible to ignore".
She added: "This is a long-standing health inequality that successive governments have failed to tackle.
"It is clear to paediatricians that progress on childhood obesity cannot be achieved without also addressing our out-of-control rates of childhood poverty and deprivation."
Dr Stewart urged the Government to expand free school meals and scrap the two-child limit to benefit payments to lift more children out of poverty.
In Woking, 3.6% of year 6 children were also considered severely obese.
Professor Simon Kenny, NHS England’s national clinical director for children and young people, said: "Obesity can have a major impact on a child’s life – it affects every organ in the body and is effectively a ticking health time bomb for the future by increasing a child’s risk of type 2 diabetes, cancer, mental health issues and many other illnesses.
"But the NHS cannot solve this alone and continued action from industry, local and national government, and wider society together with the NHS is essential to help create a healthy nation."
A Department of Health and Social Care spokesperson said: "This government inherited an obesity crisis which is costing the NHS and the economy billions of pounds.
"We are committed to tackling this issue head on, shifting our focus from treatment to prevention as part of our 10 Year Health Plan.
"We have already made a strong start by restricting junk food advertising on TV and online, limiting school children's access to fast food, and confirming that we will take steps to ensure the Soft Drinks Industry Levy remains effective and fit for purpose."