More children in Cumbria are starting school overweight than anywhere else in England.
New figures from the Local Government Association show that 28.2% of children, aged four and five, are classed as overweight or obese.
However, that rate falls to 19.8% by the time they leave primary school.
Across England, figures show more than 22,000 out of 556,000 children in Year 6 are classed as severely obese. Whereas 15,000 out of 629,000 children, aged four and five, are classed as severely obese.
The Local Government Association (LGA), which obtained the figures, said this shows children are gaining weight at a drastic rate as they go through schools.
The LGA, which represents 370 councils in England and Wales, warned the severe child obesity rates are contributing to a “multi-billion pound ill-health time bomb”.
Severe obesity puts people at serious health risks, including diabetes, heart disease, stroke and cancer. Severe obesity can also shorten a person’s life by 10 years – an equivalent loss to the effects of lifelong smoking.