Children eat more after seeing just five minutes of junk food ads, study finds

The Guardian

11-05-2025

Children will eat significantly more calories in a day after watching just five minutes of junk food advertising, according to a groundbreaking study.
Young people who saw or heard adverts for products high in saturated fat, sugar and salt consumed an average of 130 extra calories, equivalent to two slices of bread, the research found.
The study involved 240 seven- to 15-year-olds, from schools in Merseyside. On two separate occasions, they were shown or played five minutes of junk food adverts and then non-food adverts.
Subsequently, they were offered snacks such as grapes or chocolate buttons, and later, lunch with a range of savoury, sweet and healthy items.
The authors calculated that, after the adverts, the children consumed 58 calories more in snacks and ate 73 more calories for lunch than after exposure to non-food ads.
The research, to be presented at the European Congress on Obesity in Málaga, Spain, also found that the impact on calorie intake was the same whether the adverts were for specific foods or were generic adverts for fast food brands.
And it was unaffected by the type of advert, such as video with sound, social media posts, podcast adverts, and posters or billboards.
Emma Boyland, the lead author of the study and professor of food marketing and child health at the University of Liverpool, said: 'This is the first study to show that brand-only food advertising affects what children eat.
'We also showed that children don't just eat more immediately following food advertising, they actually ate more at the lunch meal as well, a couple of hours after they had seen the advertising.
'The foods that we served them weren't the same foods that were shown in the advertisements and were presented with no branding information. So it wasn't that they were driven to buy the particular food or go and consume fast food, it was just a prompt to consume what was available.'
Experts warned that the findings revealed a loophole in the government's proposed ban on junk food TV adverts before 9pm, due to come into effect in October.
Katharine Jenner, the director of the Obesity Health Alliance, said the study must send 'a clear message to policymakers: food advertising is driving excess calorie intake in children'.
She added: 'From October, new restrictions will limit unhealthy food adverts on TV before 9pm and online at any time – a vital step forward that will protect children from the worst offenders.
'But loopholes remain. Brands will still be able to advertise to young people even without showing specific products, on billboards and at bus stops, and children living with overweight or obesity are especially vulnerable.
'If the government is serious about ending junk food advertising to children, they must close the loopholes that will allow companies to keep bombarding them.'
Dr Helen Stewart, the officer for health improvement at the Royal College of Paediatrics and Child Health, said: 'Childhood obesity is stubbornly high, with children in the most deprived areas facing rates more than twice as high as their peers. Paediatricians recognise that tackling this crisis is impossible without also introducing necessary measures such as regulations on the food industry.'
A Department of Health and Social Care spokesperson said: 'This government has taken bold action to end junk food ads targeted at children on TV and online, which will reduce the number living with obesity by 20,000 and deliver health benefits to the economy worth £2bn.
'We are encouraging the industry to focus on healthier options by allowing companies to advertise healthier alternatives in identified categories.'