Key Development

A new study from Edith Cowan University (ECU) in Western Australia has found that short advertisements promoting healthy eating can reduce cravings for junk food — and in some cases, a 15-second message works better than a traditional 30-second commercial. Dr Ross Hollett, who led the research, examined how the length and message style of junk food and anti-junk food advertisements affect adults immediately after viewing them.

How the Study Worked

The research team studied 505 Australian adults. They randomly showed participants either a junk food advertisement or an anti-junk food advertisement. After watching the ad, participants reported their immediate cravings and whether they intended to eat junk food. Researchers divided participants into two groups:

• Adults in the normal BMI range (18.5–25)
• Adults classified as overweight (25+) or living with obesity (30+)

What Researchers Found

Surprisingly, a single junk food advertisement did not significantly increase cravings or the intention to consume junk food — even when participants saw foods they liked. However, anti-junk food advertisements reduced cravings and the intention to eat unhealthy foods in both BMI groups. The impact depended on how the message was framed and how long it ran.

For adults in the normal BMI range, a 15-second anti-junk food advertisement reduced cravings more effectively than a 30-second version. For adults who were overweight or living with obesity, a short 15-second advertisement that encouraged healthy food choices worked better than one that criticised junk food. Dr Hollett explained that short, clear, and positively framed messages may have a stronger immediate effect, especially among people at higher health risk.

Why It Matters

Junk food advertising in Australia remains largely unregulated, despite public health concerns. The study suggests that public health campaigns can influence eating intentions — especially when they use short, positive messaging. Researchers believe that increasing the frequency of brief, encouraging health messages could help reduce the risks linked to junk food consumption.

The study, titled “Length and framing of anti-junk food ads impact inclinations to consume junk food among normal weight, overweight, and adults with obesity,” was published in the Health Promotion Journal of Australia.

News Medical