Just 5 minutes of advertising is enough to worsen a child's eating habits

They say we eat with our eyes. It is certainly with our sight that we learn to desire food, especially the junk food that populates online and television advertisements. Nothing strange, given that companies spend millions every year on their advertising campaigns. What may be surprising, however, is how rapid the effect is: just five minutes of exposure to advertisements for snacks and foods rich in saturated fats, sugar and salt, is enough to increase children's daily energy intake by 130 kcal. This was revealed by a study by the University of Liverpool, recently presented during the European Congress on Obesity in Malaga.

Prohibit the sale

In fact, for some time now, in Europe as in the rest of the world, people have been thinking about the possibility of banning, or at least regulating, advertisements for products that can be classified as junk food aimed at children. An idea that is also liked by the WHO, which has supported a ban during protected time slots as a strategy to combat the worrying increase in childhood obesity. But it is struggling to find the necessary legislative support, also due to the lack of scientific research in this field. Something that the Liverpool researchers intend to remedy with their study.

“Our findings provide crucial new insights into the prevalence, nature and impact of unhealthy food marketing across different media on the eating habits of young people,” said Emma Boyland , a researcher from Liverpool who led the study. “Even a brief exposure to an advert for a food high in fat, salt and sugar can lead to excess calorie consumption and potentially weight gain, particularly among young people who are more susceptible to the effects of marketing and whose eating habits can influence their health for the rest of their lives.”

What the research says

The research involved 240 children aged between seven and 15, to test the effects of different forms of advertising - direct advertising of unhealthy foods, marketing limited to the brand of the company that produces the food, video advertising, audio advertising and static billboards - on different sociodemographic targets. In two different sessions, the children watched for five minutes various types of commercials (audio, video, with or without images of food) related, or not, to junk food. They were then given free access to the food of their choice for the rest of the day.

The researchers monitored how their eating habits changed, and the total caloric intake related to the foods consumed at lunch and snack, after watching the commercials. The results indicate that the type of advertising does not influence the behavior of the children, nor do the sociodemographic characteristics of the families they come from. On average, however, all children after five minutes of exposure to junk food commercials consumed 58.4 kcal more from snacks and 72.5 at lunch.

The body mass index

The only variable that seems to influence the reaction to the ads is the body mass index: for each point increase in BMI, children would consume 15 kilocalories more in response to the commercials. "Our results show that the marketing of unhealthy foods leads to a sustained increase in calorie intake in young people, of a magnitude sufficient to cause weight gain over time - concludes Boyland -. These new data will be useful for developing urgent restrictive policies towards the marketing of food products, in order to protect the health of children".