Councils say they plan to spend less money fighting obesity.
Figures from the Local Government Association (LGA), which represents more than 370 councils, show they are forecast to spend £127 million in 2016/17 - down from their estimated spend of £140 million in 2015/16.
In 2014/15, councils spent £126 million, and £112 million in 2013/14 on tackling obesity, amounting to a half a billion spend from 2013 to 2017.
Councils blamed their drop in spending on Government cuts to public health grants, saying these were having an impact on their ability to tackle obesity in adults and children.
The LGA said the Government has reduced the public health grant by £331 million from 2016/17 to 2020/21. This is in addition to a £200 million in-year cut in 2015/16.
Councils use the money for a range of services - such as weight-loss courses, exercise referral schemes and free or reduced-cost sport and swimming.
Councils also run the Government's National Child Measurement Programme in schools, where children are weighed and measured when they start and leave primary school.
In 2014/15, one in 10 four and five-year-olds and one in five 10 and 11-year-olds were found to be obese.
The figures come amidst growing frustration over delays to the Government's childhood obesity strategy, which was due to be published last year.
Experts from Action on Sugar accused the Government of watering down original aims in face of pressure from the food and drinks industry.
A leaked copy of the report seen last week contained no specific details about marketing restrictions on junk food to children and a series of other "pathetic" responses, the group said.
Izzi Seccombe, from the LGA, said: "The staggering amount of money councils are having to plough into obesity prevention work shows the sheer scale of the crisis we face."
She added: "From working with children who are obese and overweight to encouraging children to cut their consumption of sugary drinks, since taking over responsibility for public health three years ago, local authorities have been leading the way in the fight against obesity.
"But we would like assurances from the Government's new administration that the long-awaited childhood obesity strategy is still on track and that it includes tough measures that will help to reverse the rise in costs and children becoming obese."
A Department of Health spokeswoman said: "Over the next five years we will invest more than £16 billion in local government public health services and an extra £10bn in the NHS. Local councils are doing excellent work to help make their communities healthier.
"We are committed to tackling obesity - we have already taken a bold step by announcing the soft drinks industry levy and we will go further through our childhood obesity strategy."