Preschool children aged between three and five know more about unhealthy food brands than healthy ones that are advertised at a similar level, according to research findings by Safefood.
It also found that preschool children recognise twice as many unhealthy food and drink brands as healthy ones.
The study involved 172 children and was carried out by University College Dublin and Queen's University Belfast.
Dr Mimi Tatlow-Golden, lead author of the research, said the study compared advertising for less healthy brands with that for healthy ones.
Speaking on RTÉ's Morning Ireland, she said: "We think this is really surprising because we weren't comparing widely-advertised brands like crisps or chocolate cereal with broccoli.
"We were comparing equally frequently advertised brands for less healthy foods with ones that are considered more healthy like yoghurts and smoothies."
Dr Tatlow-Golden added that children with parents who eat less healthily recognise unhealthy brands more than preschool children whose parents eat healthily.
"Kids who watch more TV and have parents who eat less healthily have a lot more recognition for unhealthy brands but the same is not happening for healthy foods.
"So we think that there's something going on here in terms of kids' inherent appeal to foods that are high in fat, salt and sugar."
She added: "We need to think more carefully about how we're marketing these types of foods because parents are buying these foods for their kids, eating them in front of their kids and also we need to think in terms of education about such foods."
Dr Tatlow-Golden said restrictions are needed on programming other than those that are applied to children's television.
"Sugar is inherently appealing to the human palate", she said.
"So the implication is why are we advertising these foods at times when young children are watching TV.
"We have restrictions in place which apply to children's programming but the rest of the time young children are being exposed to these ads," she added.
