Flinders University researcher Jane Scott and colleagues found that babies as young as four weeks old are growing up on a diet of biscuits, ice cream and soft drinks – all high fat, salt and sugar foods – despite health authorities recommending exclusive breastfeeding to six months of age.

"This is a worry because eating habits developed early in life usually continue throughout a person's lifetime – and an overweight child is much more likely to become an overweight adult," said Scott. This kind of a diet is also giving rise to the problem of children being overweight early in life.

"What newborns eat does matter. Parent need more support to optimise breastfeeding initiation and duration rates, and we need ways to make it easier for parents to feed their children right," obesity expert Professor Clare Collins said.

"What happens at home has the biggest effect on what children eat, so any effort to address children being overweight and obese must start at home," she added.

She called for better support for and promotion of breastfeeding, which she said is one of the most important factors in the long-term health of newborns. The study is published in the journal Nutrition & Dietetics.