Young children who recognise unhealthy food logos are more likely to be overweight or obese, a new study has found.

US researchers tested children aged between three and five on their knowledge of various brands. The children were given pictures of food items, packaging and cartoon characters and were then asked to match them with their corresponding brand logos.

The study found that the more familiar children were with unhealthy food logos and images, the more likely they were to be overweight or obese. These logos and images covered things like fast-food restaurants, fizzy drinks and unhealthy snack foods.

"We found the relationship between brand knowledge and BMI (body mass index) to be quite robust. The kids who know most about these brands have higher BMIs," the researchers from Michigan State University said.

They noted that the results were varied, which they described as ‘a good thing'.

"Some kids knew very little about the brands while others knew them exceptionally well," they said.

Since children get most of their food messages from television, the researchers queried which was causing more harm - the unhealthy messages these children are receiving or the sedentary lifestyle associated with watching too much television.

"From our results, it would suggest that it's not the TV time itself, but rather what is learned about these brands. It's probably the developing food knowledge, not the sedentary lifestyle," they noted.

They added that it does not take long for a child to figure out what foods they like and do not like and this is something ‘that can stick with them their entire lives'.

"What we're trying to show here is just how young kids are when they develop their theory of food. As early as three years of age, kids are developing a sense of what food means to them."

Details of these findings are published in the journal, Appetite.