Despite health and fitness being more in vogue than ever, childhood obesity rates continue to rise. A new report from the World Obesity Federation warns that by 2040, the number of five- to 19-year-olds globally who are obese could increase from 180 million to 227 million. This is defined as a BMI of 30 or above – and is a risk factor for type 2 diabetes, hypertension, cardiovascular disease and a number of other serious health conditions.

These trends are also clear in the UK, where overweight and obesity rates continue to increase in children. In England, the National Child Measurement Programme (which takes height and weight data in year 6 for 94.1% of all eligible children) for 2024-25 found that 36.2% of children aged 10-11 had a high BMI (more than 25), with children in the most deprived areas twice as likely to be obese, and projections indicating that in some areas, the majority of children would be at an unhealthy weight by 2035. The UK as a whole has twice the number of overweight and obese children as either France or Italy.

Looking at Britain’s food system, this data isn’t surprising. Ultraprocessed foods often make up the bulk of school lunches, while at home, fast food and packaged options are often the cheapest choice for families, while fruit, vegetable, dairy and meat prices have risen since Brexit. We’ve seen budgets cut to schools, which covers free school meals, bringing impossible decisions over how to provide nutritious meals at very low cost.

To be fair to the UK, obesity does feel like a wave engulfing the world, one that certain governments are trying to counter by building seawalls through legislation. Some of these might be seen as a “nanny state” intervention, but doing nothing isn’t in children’s, or taxpayers’, interest.

Take South Korea, where the government has implemented “green food zones”, which state that within 200m of a school, vendors cannot sell junk food, high-calorie, low-nutrition food or high-caffeine food or drink. This has been supported by strict regulations over the targeted marketing of certain food products to children. Researchers concluded that environmental changes to what children can access was more effective than nutrition education.

Denmark has also taken an active approach, establishing children’s obesity clinics, to which children identified as having an unhealthy weight are referred. Here, children and their parents are supported to improve diet, increase play activities and reduce sedentary time. Researchers found that BMI decreased significantly even after just one year of working with the clinic.

Closer to home, the Welsh government has been trying innovative pilot schemes to get more vegetables into school meals. In 2022, the government guaranteed a large market (school meals in Cardiff) to courgette producers with the requirement that produce met certain quality standards. Farmers scaled up their production knowing they could sell their vegetables, and wholesalers reduced prices, given the guaranteed bulk purchase. In a win-win dynamic, the Courgette Pilot gave a clear example of how to lower the price of (usually expensive) vegetables, supported local producers and get more kids eating a nutritious lunch, and is a great model of how to provide affordable, healthy food to children.

The UK prime minister, Keir Starmer, came to power aware of these challenges, and moved towards implementing policies such as banning junk food advertising online and before 9pm on TV, as well as raising the issue of “green zones” around schools. The impact of these measures will take several years to see. But there is more that could be done.

For example, free school meals are subsidised by schools’ budgets, which means that to provide these, head teachers have to cut educational activities, or not fill teacher vacancies. School lunches are often framed as a social welfare issue to ensure no child goes hungry (and getting food at the cheapest cost) instead of a preventive health intervention, which could actually save the NHS money. Food is medicine, the adage goes.

An additional cause of rising child BMI rates is the decrease in physical activity rates in children. As a society, we haven’t figured out a good way to cope with the ubiquity of screens and the linked sedentary behaviour. You only have to look at young children these days to see that running around has been replaced by sitting and watching videos on a mobile phone or tablet. In short, the next challenge for governments is to figure out how to get children under five to sit less and play more, which is underlying many of these worrying health trends.

Prof Devi Sridhar is chair of global public health at the University of Edinburgh

Prof Devi Sridhar is chair of global public health at the University of Edinburgh

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