Researchers found that preschoolers from low-income neighbourhoods in Columbus in US who ate fruits and vegetables and drank milk many times every day were just as likely to eat foods high in sugar, salt and fat as those who rarely ate healthy foods.
"We assumed that children who ate a lot of healthy foods would also be children who did not eat a lot of unhealthy foods," said Sara Anderson from Ohio State University in US.
The research team asked them about the children's diets and categorised foods and drinks into healthy and unhealthy categories.
Healthy choices included fruits, vegetables and milk. Unhealthy choices included sweetened drinks, fast food, sweets and salty snacks.
Regardless of age, there was no evidence kids who frequently ate fruits and vegetables and drank milk were any less likely to partake in the unhealthy foods.
About half the children in the study ate fruit two or more times a day. Some rarely ate vegetables, but more than a third had them multiple times a day. Most of the children drank milk at least once a day.
"There has been a kind of assumption there that if you encourage people to adopt healthy eating that it naturally leads to a decline in unhealthy eating," said Phyllis Pirie from Ohio State University.
"Efforts to lower childhood obesity rates often focus on adding 'good' foods, rather than on avoiding 'bad foods,' she added.
The findings were published in the Maternal and Child Health Journal.
