As a result, calls have increased for the Government to take further action to prevent youngsters consuming junk food and sugary drinks, as the level of severe obesity hit a record high across England.
NHS Digital figures show that 19 per cent of year six pupils in Nottinghamshire in 2017-18 were obese, of which 3.8 per cent were severely obese.
Additionally, 14 per cent of year six children were overweight.
That means 33 per cent of Nottinghamshire’s youngsters are unhealthily overweight when they finish primary school.
Across England, 4.2 per cent of 10 and 11-year-olds are severely obese, a record high.
Caroline Cerny, of the Obesity Health Alliance, a coalition of leading health charities, medical royal colleges and campaign groups, said: “We can do something about this.
“The ever increasing number of children living with obesity is a clear reflection of the unhealthy wider environment that pushes us towards sugary and fatty food and drinks.
“We need to start with reducing the number of junk food adverts children see before a 9pm watershed, restrictions on junk food promotions in supermarkets and the food industry stepping up efforts to reduce sugar and fat from everyday foods.”
Despite school meals getting healthier, the proportion of obese 10 and 11-year-olds in year six has risen from 18 per cent in 2013-14.
The figures are from the National Child Measurement Programme.
Each year officials measure the height and weight of more than one million children, in reception and year six classes to assess childhood obesity.
The Government works out obesity using the 1990 British growth reference chart, a large collection of statistics used to determine a child’s body mass index (BMI).
It defines a child as obese if their BMI is in the chart’s top five per cent, and overweight if they are in the top 15 per cent.
Children’s BMI is measured differently to adults, and is calculated using age and gender as well as height and weight.
Obesity can lead to heart problems and type 2 diabetes later in life, as well as psychological issues such as low self-esteem and depression.
The data shows that children often develop weight problems while at primary school.
In 2017-18, just 10 per cent of Nottinghamshire’s children were obese in reception.
Across England one in five pupils in year six was obese.
Children from the most disadvantaged backgrounds were more than twice as likely to be obese than those from the wealthiest areas.
Dr Max Davie, of the Royal College of Paediatrics and Child Health, said the figures were ‘totally unacceptable’.
He added: “However, the Government has already shown it is serious about tackling childhood obesity and I am reassured that these stats will begin moving in the right direction.”
Steve Brine MP, a public health minister, said: “Obesity is a problem that has been decades in the making – one that will take significant effort across government, schools, families and wider society to address.
“We cannot expect to see a reversal in trends overnight – but the Government has been clear that it is willing to do whatever it takes to keep children healthy and well in this country.
“It has already removed tonnes of sugar from children’s diets through the sugar tax, which has funded vital school sports and breakfast programmes, and this summer it announced the second chapter of its childhood obesity strategy with a series of bold plans to halve child obesity by 2030.”