It also reveals that claims such as "it's a good source of calcium and protein" significantly increase the likelihood that children will go the junk food option.
The findings of the Cancer Council of Victoria study have prompted calls to regulate nutrient content claims and to ban celebrity endorsement for junk foods.
Jane Martin, of the Obesity Policy Coalition, which also includes the Cancer Council, said: "We'd like to see the nutrient content claims not appear on unhealthy foods.
"Similarly we are also very concerned about the role that sports celebrities play and we'd like to see them not endorse unhealthy products - particularly when we have 25 per cent of children who are overweight or obese."
The study of 1300 Melbourne children, which was published in the journal Pediatric Obesity, found celebrity endorsements were especially effective on boys, increasing the odds they'll pick junk food by 65 per cent.
It also showed claims such as "high in calcium" boosted by 80 per cent the chance of an 11-year-old opting for a less healthy food.
The study tested responses of grade 5 and 6 children to nutrient content claims, sports celebrity endorsements and premium offers. The children were shown mocked-up versions of products with sports stars, offers for items such as free movie tickets, and claims about the nutritional benefit of products.
It found that premium offers had less impact on children's choices.
Ms Martin said nutrient claims could influence parents, but it was interesting to see they were also quite powerful with children. "And then they use it to pester their parents," she said.
"I think it would be fantastic if our children were protected from this."
Ms Martin criticised fast food giants who sponsor children's sport, such as KFC, McDonald's and Milo, for sending mixed messages to children.
She said regulations around high-level health claims had been introduced, but this should be extended to nutrient health claims.
