Children from deprived areas in England are significantly more likely to be obese, according to new figures.
The latest statistics for children aged 10 to 11 show that 24.7% from low-income areas are obese, compared to 13.1% in the least deprived locations.
There is a doubling of the overall obesity rate from youngsters aged four to five (9.5%) to the end of primary school (19.1%).
The data were collected during the 2013/14 school year and have been released by the Health and Social Care Information Centre (HSCIC).
Eustace de Sousa, national lead for children, young people and families at Public Health England (PHE), described the figures - which are for children in state schools - as "deeply concerning".
He said: " We know that over a third of children leaving primary school are overweight or obese, which makes them much more likely to be overweight or obese as adults and considerably increases their risk of developing Type 2 diabetes and other serious health problems.
"Tackling obesity, and in particular childhood obesity, has always been a national priority for PHE."
In reception class, more than one in five (22.5%) children were classified as overweight or obese, 0.3% higher than in 2012-13.
In year 6, over a third (33.5%) were overweight or obese - a rise of 0.2% from last year.
Mr de Sousa said: " Parents and carers can help their children maintain a healthy weight by following a balanced diet, keeping an eye on portion sizes and limiting sugary drinks and sugary or fatty snacks.
"Change4life offer simple, affordable recipes including family meals for £5 and ideas on small swaps families can make to their diets, like swapping sugary drinks for diet or sugar free versions, water or lower fat milk, to remove excess calories.
"Children also need a minimum of 60 minutes of exercise each day, which can be achieved in one session or through shorter bursts of 10-minute activity."
The local authority with the highest obesity rate for reception aged children was Hackney (14.4%), while Windsor and Maidenhead was the lowest (5.5%).
In year 6, the range was from 26.7% in Southwark to 11.1% in Richmond upon Thames.
The prevelance of obesity was found to be higher for boys in both year groups. In reception, 9.9% of boys and 9% of girls were classified as obese, while in year 6 the rate was 20.8% for boys and 17.3% for girls.
Meanwhile t he overall prevalence of underweight children was lower in reception (0.9%) than in year 6 (1.4%).
Dr Colin Michie, chairman of the nutrition committee at the Royal College of Paediatrics and Child Health, said: " The headline that poor children are more likely to be obese is nothing new. But what is startling is the gulf between health outcomes for rich and poor, the fact that childhood obesity is continuing to rise and children are getting fatter younger.
"We have to get away from the idea that, just because a child grows up in a low-income area or in a low-income family, it's somehow accepted that they will be overweight or obese.
"Interventions for tackling the UK's obesity crisis must concentrate on where it is most needed. It is ridiculous that most junk food is cheaper than healthier alternatives, so a potential tax on foods high in salt, sugar and far should be explored.
"We need to make sure all schools teach cooking and nutrition, so that children are brought up knowing the importance of eating the right food and having the skills to cook it. And local authorities must consider the impact on health and well-being when they are planning new development so that children have safe places to play and exercise.
"Despite being one of the richest countries in Europe, we are one of the most unequal. Unless we bridge the gap between rich and poor, we will continue to fail not only the current, but also future generations of children."