According to a recent study, the brains of kids are imprinted with logos of fast-food companies.
The study, conducted at the University of Missouri-Kansas City and the University of Kansas Medical Center, found that the pleasure and appetite centres of the brains light up when children are shown advertising images such as the McDonald's logo.
But the same areas do not respond to well-known logos that are not to do with food, the Independent reported.
Scientists suggest fast-food firms are tapping into the reward areas of the brain, and that these develop before the regions that provide self-control, leading to unhealthy choices.
"Research has shown children are more likely to choose those foods with familiar logos. That is concerning because the majority of foods marketed to children are unhealthy, calorifically-dense foods high in sugars, fat, and sodium," said Dr Amanda Bruce, who led the study.
The study selected 120 popular food and non-food brands, including McDonald's and Rice Krispies, and BMW and FedEx.
They used a type of MRI scanner - functional magnetic resonance imaging - which homes in on changes in blood flow: when areas of the brain become more active, blood flow increases.
Scans were carried out on children aged 10 to 14 as they were exposed to 60 food and 60 non-food logos. The results showed the food logos triggered increased activity in areas of the brain known to be involved in reward processing and in driving and controlling appetite.
The finding comes in the wake of research which showed advertising had a pronounced effect on children's eating habits. Children who tasted two identical burgers, one in a plain box and one labelled McDonald's, preferred the latter.