In recent weeks OHA, and our colleagues at the Royal College of Paediatrics and Child Health (RCPCH) have received several requests from journalists for data and comments explaining the impact of lockdown on childhood obesity levels.

The simple answer is that we just don’t know…

Information on prevalence of childhood obesity in England is collected yearly through the National Childhood Measurement Programme (NCMP). Children in reception (aged 4-5) and year six (aged 10-11) have their BMI measured and this data is then collated by NHS Digital and published yearly in the Autumn. There have been challenges around the use of BMI in children at an individual level, but at a population level it’s generally a very effective way for us to monitor trends in child weight status.

The latest NCMP data was published in October 2020 and spans the 2019/20 school year. As the first lockdown led to school closures between March and June 2020, the measurement programme was not carried out in full.

What may have affected child weight in lockdown?

The advice to stay at home, restrictions on how and when people can leave the house, playground closures and school closures are all likely to have had an impact on children’s health more broadly. Younger children in particular tend to get their physical activity by play, rather than formal exercise. Playgrounds being cordoned off and lack of school playground games is likely to have led to a drop in their activity. Opportunities for active travel, such as walking, cycling or scooting to school or nursery will also have disappeared. Combined with more sedentary behaviour from staying at home, this could had an impact on children’s health, particularly in children with little or no access to outside space.

Reduced incomes and rising food insecurity from the economic fall-out of COVID and the impact of losing access to breakfast clubs and free school meals for some pupils may have also led to changes to family diets which are often associated with poor nutrition because access to healthier food is limited.

More snacking and exposure to junk food adverts?

Several surveys have shown adults and young people reporting snacking more in lockdown, and this is likely to extend to children too. Snack food like crisps and biscuits tends to be high in calories and low in nutrients .

The pandemic has led to children spending more time online to study, play and socialise. We know that children who spend more time online are exposed to more junk food adverts, and that food advertisers have been working hard to keep their unhealthy products in the spotlight throughout the pandemic. Given the wealth of evidence that seeing junk food adverts influences children’s food choices and how much they eat, this additional screen-time could also have an impact on child health.

A rising issue with eating disorders?

It’s important to note that lockdown is likely to have had a wide-ranging impact on children’s eating behaviours. Colleagues at the RCPCH have raised concerns about a rise in eating disorders among children during lockdown with pediatricians noting a rise in cases of young people presenting with symptoms and a trend towards more severe symptoms. It should be recognised however that eating disorders are complex. Paediatricians working with children with eating disorders think there are a number of factors that are contributing to this rise.

What next?

It’s clear that the pandemic will have had a profound impact on children’s physical and mental health, and it will take some time to fully understand the full impact.

NHS Digital is due to publish NCMP statistics in Autumn, but it is unclear how the data collection will have been affected by school closures in 2021.

One positive sign is the continued momentum of Government’s efforts to improve children’s health with new restrictions on junk food advertising and promotions, including a 9pm watershed on unhealthy food adverts on TV and potentially a total restriction online. While we remain uncertain about the full impact of lockdown on children’s health, we can be absolutely sure that these evidence-based measures are an important step towards protecting children’s health in the longer term.