A recent study by Edith Cowan University (ECU) has found that short advertisements promoting healthy eating can lower cravings and intentions to consume unhealthy foods. The research, led by Dr. Ross Hollett, examined how the duration and message framing of junk food and anti-junk food ads affect immediate cravings among adults with different Body Mass Index (BMI) categories.
The study included 505 Australian adults who were randomly shown either a junk food or an anti-junk food advertisement. Participants then reported their immediate cravings and intentions to eat unhealthy foods. The results were analyzed in two groups: those within the normal BMI range (18.5–25) and those classified as overweight (25+) or living with obesity (30+).
Researchers found that exposure to a single junk food advertisement did not significantly increase cravings or intentions to eat junk food, even when participants viewed foods they liked. However, anti-junk food ads reduced both cravings and consumption intentions across all BMI groups.
The effectiveness of these ads depended on their length and framing. For individuals in the normal BMI range, a 15-second anti-junk food ad was more effective than a traditional 30-second version.
"For some viewers, a short, sharp message may have more immediate impact than a longer ad," said Dr Hollett.
For those classified as overweight or living with obesity, 15-second advertisements that encouraged healthy choices worked better than those criticizing junk food.
"This suggests positively framed health messages may resonate more strongly with audiences carrying greater health risks," Dr Hollett said.
He added: "If we're investing in public health campaigns, it's important to know not just whether they work, but for whom and under what conditions."
Dr Hollett suggested that increasing the frequency of brief, positive health messages could help reduce public health risks related to junk food consumption.
The findings are published in the Health Promotion Journal of Australia.
