More than half (52%) of young people have been exposed to junk food promotions on social media in the past month, according to new research from Cancer Research UK.
The ‘Digital Influence’ study found posts promoting high fat, salt and sugar (HFSS) products came from both businesses and influencers. Nearly four in 10 young people who saw the content engaged with it by liking, commenting or sharing, with influencer-led posts proving more influential than business-led adverts.
Cancer Research UK surveyed more than 4,000 11-to-21-year-olds. Alongside the survey, 43 young people took part in focus groups, while 46 used interactive tools to record and reflect on their social media use.
Participants reported seeing HFSS content in a wide variety of formats, including posts from restaurants, influencer-led restaurant reviews, cooking videos featuring HFSS ingredients, ‘mukbangs’ (live streams of people eating large amounts of food) and viral eating challenges.
The young people who took part in the qualitative research said HFSS products appeared frequently in their online worlds. This was passively via algorithm-driven feeds and actively, through content from creators they follow – often those specialising in food content.
One 15-year-old participant reported that “at least every two minutes” they’re on Instagram they see at “least one food-related post”.
Cancer Research UK warns obesity is the second biggest cause of cancer in the UK after smoking, with rates of obesity rising in young people. Previous studies found simply viewing images of HFSS foods can trigger cravings that are difficult to resist.
New restrictions
The findings come ahead of new restrictions on how ‘less healthy’ food and drink (LHF) products can be advertised.
From 1 October 2025, advertisers have agreed to comply with restrictions banning LHF promotions online and on TV before the 9pm watershed.
Under the rules, influencers cannot name or show products, in their packaging or out, if recognisable. Organic influencer posts will remain allowed, but cannot be boosted with paid spend. Brands can still post on their own channels, but cannot promote the content through paid media, provided they adhere to existing HFSS rules.
In January 2026, the Advertising Standards Authority (ASA) will have full legal enforcement powers and separate guidance will apply. Government modelling suggests this could prevent more than 20,000 cases of childhood obesity.
The research highlights how heavily young people are exposed to commercial content online. Currently, 63% of eight-to-11-year-olds have at least one social media profile, rising to 92% of 12-to-15-year-olds and 95% of 16-to-17-year-olds. At least 11% of 11-to-17-year-olds admit to setting their age to 18+ to bypass restrictions.
What’s more, 21% of adolescents say they spend five hours or more a day on social media, providing many opportunities for exposure to influential content.
A meta-analysis studying advertising and young people’s critical reasoning abilities shows children and young people struggle to identify and critically evaluate advertising, especially in digital formats. Even when they recognise adverts, they are not necessarily protected from their influence.
As a result, many young people underestimate how often they are marketed to, and how it shapes their behaviour and habits. Participants in Cancer Research’s study often framed eating HFSS foods as a matter of personal choice rather than the result of marketing.
Most believed their online activities (77%) and profile data (62%) influenced the adverts they saw, while only 17% thought offline activity played a role and 7% assumed ads were shown at random.
“Planned restrictions on junk food advertising online are a vital step to protect young people’s health,” says Cancer Research UK prevention policy manager Liv Cheek.
“However, these measures must be properly enforced and strengthened by closing any remaining gaps in the online marketing rules. We urge the UK government and regulators to take bold action to shield young people from harmful marketing that could increase their risk of obesity and cancer in the future.”
The study also found high levels of exposure to other age-restricted products. One in five young social media users said they had seen posts relating to cigarettes from businesses in the past month, while one in four reported seeing similar content from influencers.
Almost a third of respondents reported seeing vape-related posts from businesses, rising to nearly four in 10 when it came to influencers. Exposure was particularly high among those who had previously vaped.
While a minority of participants felt this type of content could subtly increase the appeal of vaping, the majority expressed negative views and believed vapes to be more harmful than often portrayed.
Alcohol content was also widespread. More than a third of young people reported seeing posts from businesses in the past month, while almost two in five said they had encountered influencer-led alcohol content.
Cancer Research UK is calling on the government, regulators and enforcement bodies to communicate existing and new guidance/legislation, “strengthen and enforce” advertising laws and monitor online platforms “more effectively”. The charity also wants to ensure enforcement agencies are receiving sufficient funding, leading to healthier digital environments being created for young people.
