Impact of non-HFSS advertising on food selection: An online Randomised Controlled Trial (RCT)

A new online trial will test whether adverts for healthier versions of junk foods make people more likely to choose the original, unhealthy products instead. The problem is a loophole in advertising regulations. Brands can promote a low-fat, low-sugar version of a product—a non-HFSS variant—without breaking rules designed to curb junk food marketing. But these adverts may still trigger mental associations with the full-fat, full-sugar original, undermining the policy’s intent. No one has yet tested this spillover effect directly. If the trial shows that non-HFSS advertising does boost selection of the unhealthy counterpart, regulators could tighten the rules to close this gap. That would mean fewer loopholes for food companies to exploit, and more effective protection for public health—especially for children, who are most exposed to food marketing. If the trial finds no such effect, current advertising restrictions may be sufficient. This is applied, policy-relevant research with a clear practical endpoint. It does not explore fundamental mechanisms of food choice or advertising psychology; it tests a specific regulatory question under controlled conditions.