Just 5 Minutes of Junk Food Ads Can Make Kids Eat 130 Extra Calories: Study

It takes just five minutes of junk food advertising to tip the scales on a child’s daily calorie intake. The study showed that children and adolescents who saw or heard advertisements for products high in saturated fat, sugar and salt (HFSS) consumed an average of 130 extra kilocalories per day. This is equivalent to the calories in two slices of bread.

Researchers at the University of Liverpool conducted a randomised crossover trial involving 240 children aged between 7 and 15 years from schools in Merseyside.

On two separate occasions, participants were exposed to five minutes of HFSS food adverts and then, on another occasion, to non-food adverts.

Following each exposure, they were offered snacks such as grapes and chocolate buttons and later served lunch that included sweet, savoury and healthy options.

The children consumed 58 calories more in snacks and 73 more calories at lunch after watching junk food adverts, compared to after viewing non-food adverts. Overall, the study found that children consumed 130.90 extra kilocalories after exposure to junk food marketing.

Professor Emma Boyland, lead author and Professor of Food Marketing and Child Health at the University of Liverpool, said: “Our findings offer crucial novel information on the extent, nature, and impact of unhealthy food marketing via different types of media on young people's eating behaviour.”

“Even short exposure to the marketing of foods high in fat, salt, and sugar can drive excess calorie consumption and potentially weight gain, particularly in young people who are more susceptible to advertising and whose eating patterns influence their lifelong health,” she added.

The impact on calorie intake was found to be the same regardless of whether the ads promoted specific products or were brand-only. The effect was also consistent across different types of media, including videos with sound, social media posts, podcast adverts, posters and billboards.

“This is the first study to show that brand-only food advertising affects what children eat,” said Boyland. “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 have said the findings reveal limitations in the UK government’s proposed ban on junk food TV adverts before 9 pm, which is scheduled to begin in October.

Katharine Jenner, Director of the Obesity Health Alliance, said: “This study must send a clear message to policymakers: food advertising is driving excess calorie intake in children.”

“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, 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 spokesperson for the Department of Health and Social Care 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.”

Unhealthy weight gain in children is associated with conditions such as obesity, hypertension, diabetes and cancer. Researchers hope the study will support the design of stronger food marketing policies to better protect children’s health.