A new study from Edith Cowan University (ECU) in Australia suggests that very short health advertisements could help people resist junk food cravings and make healthier choices.
Surprisingly, the research found that a quick 15-second message may sometimes work better than the traditional 30-second commercial.
The study, led by Dr. Ross Hollett, looked at how both junk food ads and anti-junk food ads influence people’s immediate desire to eat unhealthy foods.
Researchers were especially interested in whether responses differed among adults with different body weights.
Junk food advertising is common in Australia and many other countries, and it is often aimed at encouraging people to buy high-sugar, high-fat, and highly processed foods.
Public health experts worry that this type of marketing contributes to rising rates of obesity and related diseases. Anti-junk food ads, on the other hand, try to discourage unhealthy eating by warning about health risks or promoting better food choices.
To test the effects, the researchers recruited 505 Australian adults. Participants were randomly shown either a junk food advertisement or an anti-junk food advertisement. After watching, they reported how strong their cravings were and whether they intended to eat junk food. The researchers grouped participants by Body Mass Index (BMI), comparing those in the normal range with those who were overweight or living with obesity.
The results were unexpected. Seeing a single junk food advertisement did not significantly increase cravings or intentions to eat unhealthy foods, even when participants were shown foods they liked. However, anti-junk food ads did reduce cravings and intentions across all groups.
The way the message was delivered mattered. Among people with a normal BMI, a short 15-second anti-junk food ad was more effective than a longer 30-second version. According to Dr. Hollett, a brief, direct message may capture attention and create a stronger immediate reaction than a longer one.
For participants who were overweight or living with obesity, the type of message made an even bigger difference. A short ad that encouraged healthy eating worked better than one that criticized junk food. Positive messages seemed to resonate more strongly with people who may already feel at risk from diet-related health problems.
The findings suggest that public health campaigns could become more effective by using short, encouraging messages rather than longer warnings. Increasing the frequency of these brief ads might help reduce unhealthy eating habits across the population.
Dr. Hollett emphasized that understanding how people react in the moments right after seeing an advertisement is important. If governments and health organizations want to invest in campaigns that truly improve public health, they need to know what works, for whom, and why.
The study was published in the Health Promotion Journal of Australia and highlights a simple idea: sometimes, a short message delivered at the right moment may be enough to nudge people toward healthier choices.
