New Research Reveals Short Exposure to Junk Food Advertising Significantly Increases Caloric Intake in Children
An eye-opening study presented at the European Congress on Obesity 2025 in Malaga, Spain, reveals that even brief exposure to unhealthy food advertisements causes children and adolescents to consume substantially more calories throughout the day. Conducted by researchers from the University of Liverpool, this randomized crossover trial provides compelling evidence that just five minutes of viewing ads for foods high in saturated fat, sugar, and salt (HFSS) leads young viewers to increase their daily calorie intake by approximately 130 kilocalories — roughly equivalent to the energy found in two slices of bread.
This groundbreaking research emerges amid a global spotlight on childhood obesity and growing calls for stricter regulations on unhealthy food marketing. Governments across Europe and worldwide consider limiting children’s exposure to junk food advertisements as a key strategy to curb escalating obesity rates. The Liverpool study sheds new light on the potency of advertising stimuli, underscoring the urgent need for policies that effectively protect young people’s health.
The investigators recruited 240 children aged 7 to 15 from schools in Merseyside, UK, to participate in a carefully controlled experimental design. On two separate days, each child was exposed to five-minute advertisement reels, one featuring HFSS food ads and the other showcasing non-food advertisements as a control. These ads varied in format—ranging from traditional TV-like audio-visual commercials to visual-only posts, audio ads such as those found in podcasts and radio, and static images like paper billboards—to assess whether the medium influenced consumption behaviors.
Following exposure, the researchers measured children’s spontaneous (“ad libitum”) intake of snacks and lunch items. They also recorded height and weight to calculate body mass index (BMI), while area-level socioeconomic status (SES) was derived based on participants’ home postcodes using the 2019 English Index of Multiple Deprivation. This comprehensive approach allowed the team to analyze not only immediate eating behavior but also potential moderating effects of socioeconomic background and body composition.
Findings revealed a striking increase in calorie consumption after HFSS ad exposure: participants ate on average 58.4 additional calories from snacks and 72.5 more calories at lunch compared to when they viewed non-food ads. The combined increase in caloric intake totaled nearly 131 calories per day. Importantly, the nature of the advertisement content—whether brand-only, displaying logos and branding without product images, or product-based—did not significantly affect this outcome. Brand-only ads were just as effective as product-heavy advertisements in driving increased food consumption.
This revelation carries profound policy implications. Currently, many advertising restrictions focus explicitly on product images and overt food promotion, often neglecting brand-only marketing which, as this study demonstrates, has an equally potent effect on children’s eating behavior. “Our study is the first to conclusively show that brand-only food advertising, a regulatory blind spot globally, can increase children’s caloric intake,” explains Professor Emma Boyland, lead author and expert in food marketing effects on youth.
Interestingly, the type of media platform on which the ads were presented—whether audio-visual like television, visual-only like social media posts, audio formats such as podcasts, or static billboards—did not moderate the increased intake. This finding suggests that the impact of HFSS advertising transcends medium, emphasizing the pervasive influence of unhealthy food marketing regardless of delivery format.
Socioeconomic status did not show a moderating effect on calorie consumption changes, indicating that children across various SES backgrounds are susceptible to the marketing cues promoting unhealthy eating habits. This raises important considerations about the universal reach of such advertising practices and their potential to exacerbate childhood obesity regardless of socio-demographic factors.
However, body mass index (BMI) did play a significant role: for every standardized unit increase in BMI (adjusted for age and sex), children consumed an additional 17 kilocalories following exposure to HFSS ads. This suggests that children with higher BMI scores may be more vulnerable to the influence of unhealthy food marketing, potentially contributing to a feedback loop of excessive calorie intake and weight gain over time.
The mechanisms through which advertising prompts increased consumption are multifaceted. Exposure to HFSS marketing can trigger automatic, unconscious responses such as craving, cue reactivity, and heightened impulsivity. Advertising manipulates psychological drivers by creating positive associations with brands and foods, bypassing rational decision-making and altering reward pathways in the brain, particularly in young, impressionable minds.
Given these insights, the study’s authors advocate for urgent and comprehensive policy interventions. Restrictive measures limiting both product-based and brand-only HFSS advertising across all media platforms are essential to mitigate the harmful effects on children’s eating behavior. Such policies would protect children from exposure that leads to excess caloric intake sufficient to drive weight gain over time, ultimately combating the growing childhood obesity crisis.
This research contributes significantly to the scientific literature on the environmental determinants of obesity, highlighting the complex interplay between marketing practices, individual susceptibility, and eating behavior. The randomized crossover design allows causal inferences about the immediate impact of junk food advertising, filling critical gaps left by observational studies and enriching the evidence base policymakers rely upon.
Professor Boyland emphasizes, “Our results underscore that even minimal exposure – in this case just five minutes – to unhealthy food ads can meaningfully increase calorie consumption in children. This effect is robust across different ad content types and media, as well as socioeconomic backgrounds, making it a ubiquitous concern that demands swift regulatory action.”
In addition to informing policy, the findings resonate with parents, educators, and public health practitioners seeking strategies to nurture healthier eating habits in young populations amidst a media landscape flooded with persuasive food marketing. Recognizing the subtle yet powerful role advertising plays in daily diet choices is a crucial step toward systemic change.
As childhood obesity continues to pose major public health challenges around the world, evidence from studies like this reinforces the urgency of addressing food marketing environments. Limiting children’s exposure to HFSS advertisements—regardless of whether they showcase actual products or simply brand logos—should become a cornerstone of comprehensive obesity prevention efforts in the 21st century.
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Subject of Research: Impact of unhealthy food advertising on children’s calorie consumption and eating behavior
Article Title: Not provided in the source text
News Publication Date: 10-May-2025
Keywords: Childhood obesity, junk food advertising, calorie intake, saturated fat, sugar, salt, HFSS foods, food marketing, randomized crossover trial, brand-only advertising, media influence, body mass index, socioeconomic status
