School Absence Emerges as Overlooked Driver of Childhood Obesity Crisis

Ibbie was 12 years old when a doctor told her she might need a liver transplant. She weighed nearly 22 stone. The diagnosis came after years of struggling with her weight, but the real turning point had been the pandemic lockdowns. During that time, bullying from classmates over her size became unbearable, and she stopped going to school altogether. Away from the structure of the school day, away from the regulated meals in the canteen, away from the simple fact of having to leave the house, her weight spiraled. "When you are at home 24/7 it is very easy to go into the kitchen to get a snack," she says now. "It's not the same if you are at school."

Ibbie's story is extreme, but it is not unique. She is one of more than 6,000 children treated at the Complications from Excess Weight clinics—a network of 39 specialist NHS hubs across England designed to treat severe obesity in children. Some of these young people have mental health problems or learning disabilities. Some are neurodiverse or autistic. But nearly all of them share a single characteristic that has begun to strike senior doctors as significant: they do not attend school. The pattern is so consistent that it has prompted a shift in how clinicians think about the obesity crisis itself. School absence, they now say, is an overlooked driver of childhood obesity—a factor that has been hiding in plain sight.

The connection became harder to ignore after the pandemic. Childhood obesity had been rising in Britain for decades, but during the lockdowns, the rates exploded. The proportion of overweight and obese 10 and 11-year-olds rose from 35 percent to 41 percent, with poorer children hit hardest. Although obesity levels have declined slightly since then, they have never returned to pre-pandemic levels. One in 10 children starting school in England is now obese; by the time they leave primary school, that figure rises to one in five. Meanwhile, school absence itself has nearly doubled. In 2019, about 10 percent of pupils at English state schools were classified as persistently absent, meaning they missed at least 10 percent of classes. Now, that figure stands at 18 percent.

Professor Ken Ong, the lead clinician at Cambridge University Hospital's obesity clinic, sees the connection clearly. During the lockdowns, he notes, diets got worse, children did far less physical activity, and many became isolated. "I think these are the same factors that are and have been contributing to overweight and obesity," he says. International research supports the intuition. A meta-analysis published in 2017 that examined studies across seven countries found that an obese child was 54 percent more likely to be absent from school than a child with a healthy weight. The causality is not yet fully settled—obesity might drive absence, or absence might drive obesity, or both might be true—but the correlation is strong enough that doctors are now asking why.

The mechanisms are becoming clearer. Since the 2000s, when all four UK governments passed laws to make school lunches healthier, it has become much harder to find high-sugar or high-fat foods in most school canteens. At home, those restrictions vanish. A study from the University of Leeds found that only 1.1 percent of home-packed lunches met the nutritional standards that would apply to a meal bought at school. Exercise matters too. A British study from 2014 that measured step counts with electronic sensors found that most children are more active on school days than on weekends. And there is something else: the simple act of leaving the house, of walking to school, of being part of a structured day and a community. "The very act of leaving the house and walking to school is beneficial," says Dr. Catherine Falconer, a researcher at the UK Health Security Agency who has studied the link between school absence and child health.

Professor Simon Kenny, NHS England's national clinical director for children and young people, launched the first obesity clinics in 2021. He has been struck by how completely absent these children are from ordinary life. "I hadn't quite clocked how absent these children are not just from school but from life," he says. "You don't see them in the street or youth clubs or sports centres. They are outside of society." The toll is visible. Professor Julian Hamilton-Shield, a consultant paediatrician at Bristol Royal Hospital for Children, describes the severely obese children he treats as "the most unhappy children I have come across." Ibbie remembers dark days. The bullying became so severe that she had suicidal thoughts and attempted to take her own life. She developed symptoms of PTSD from the experience.

There are no easy fixes. Some parents hope that weight-loss drugs like Mounjaro and Ozempic might offer a shortcut, and the drugs have shown promise in some cases. Ibbie was given GLP-1 injections at age 12 and lost 10 stone. She no longer has liver failure, is no longer prediabetic, and says the treatment "completely changed my life." But Professor Ong cautions that medication alone is not enough. "Some families see weight-loss medication as a quick fix," he says. "Families who come here have very complex needs and if those aren't addressed then either the weight will come back very quickly, or the medication is papering over the many other needs of these children." The real solution, doctors argue, is getting children back into school—and treating school absence as a public health crisis rather than an education problem. The current network of 39 clinics reaches only 5 percent of the obese children eligible for treatment. The annual cost of treating obesity-related ill health across all ages in the NHS is now estimated at £12 billion. Ibbie never returned to school; she was home-schooled instead. But she has not given up on education. Inspired by her time at the clinic, she now hopes to study healthcare at college and help others the way she was helped.