More than 6,000 children living with obesity, including hundreds as young as four, have required treatment at specialist NHS weight-loss clinics, new figures reveal.

NHS England data, published for the first time, underlines the scale of the growing childhood obesity crisis.

Since the first Complications from Excess Weight clinic (CEW) opened in 2021, the NHS has treated 6,497 children and teenagers. Of these, 423 were four years old, 1,088 were aged between five and eight, 1,791 were aged nine to 12 and 3,137 were aged between 13 and 17. The age of a further 58 is unknown.

All were “extremely” overweight for their age, with the four-year-olds weighing an average of 33kg (5st 3lbs), the same weight as a typical 10-year-old. About 400 of the children treated by CEWs have had weight loss jabs as part of their treatment plans.

In order to be treated at a CEW, children must be referred by a community or hospital paediatrician, a GP or childhood mental health services and have a BMI above the 99.6th percentile as well as an illness linked to their excess weight.

New analysis of just under 6,000 children treated by CEWs, due to be presented at the European Congress on Obesity, in Istanbul, found that 17% had high blood pressure and a similar number had abnormal fat levels in their blood, while 6% had type 2 diabetes.

The research, by Sheffield Hallam University, Leeds Beckett University, the University of Leeds, the University of Bristol and the University of Sheffield, found that just under 30% had metabolic dysfunction-associated steatotic liver disease and 17% had obstructive sleep apnoea. About 9% had deliberately self-harmed, and the same proportion had anxiety. A significant number were neurodivergent. Just under 30% had autism and about 12% had attention deficit hyperactivity disorder. A further 24% had a learning disability.

Experts said the figures were extremely worrying and called for immediate action to curb sales of junk food and make healthier food cheaper.

Katharine Jenner, executive director at the Obesity Health Alliance, said: “These figures should be a wake-up call. All parents want their children to grow up healthy, yet seeing children as young as four needing specialist NHS treatment for their weight highlights just how early the drivers of poor health are taking hold.

“Children today are growing up surrounded by unhealthy food at almost every turn, leaving families struggling against a system that stacks the odds against healthier options.

“The fact that some children are already developing high blood pressure, type 2 diabetes and early signs of heart disease at such a young age underlines why prevention has to begin in the earliest years of life.

“Healthier food should be easier, cheaper and more available for everyone, no matter where they live.”

Dr Helen Stewart, officer for health improvement officer at the Royal College of Paediatrics and Child Health, said:

“It’s extremely concerning that we are seeing more and more children being treated at CEW clinics. Unfortunately, high levels of obesity continue to cause significant health problems in our young people, particularly impacting children from the most disadvantaged backgrounds, where children with obesity are at higher risk of chronic illnesses, mental health issues and potentially even a shorter lifespan.”

Further analysis presented at the conference shows that the children treated at the 39 CEWs in England were on average 10kg lighter two years later than those who only saw their GP or community health teams. The clinics, which provide tailored care, such as diet plans, mental health support and coaching, have prescribed weight loss jabs to hundreds of children aged 11 or over.

Prof Simon Kenny, national clinical director for children and young people at NHS England, said: “Severe obesity can impact all aspects of a child’s life – affecting their physical health, mental wellbeing and confidence – so it is fantastic that NHS CEW clinics are helping thousands of children and young people turn their lives around.”

People who have obesity as children are more likely to have the disease as adults, increasing their risk of developing a range of serious health conditions early, including heart disease, cancers and respiratory illness.

“In some cases, these clinics are helping children who could otherwise face a life cut tragically short – dying decades too soon – to look ahead to a full and healthy life,” Kenny added.

“Childhood obesity remains one of the biggest public health challenges facing the country, and the NHS is committed to stepping in early to help prevent serious long-term health complications.”