Australian toddlers are overloading on sugary biscuits and not getting enough iron-rich foods such as red meat, according to a snapshot of their diet.
A study of more than 500 children aged 12 to 16 months also warns parents to go easy on Vegemite, saying too much can give young children a taste for salt.
Queensland and South Australian researchers investigating what toddlers ate over 24 hours found too many were given formula instead of cow's milk, reducing their appetites and potentially giving them a fear of trying new foods.
While most children ate fruit and vegetables, only half achieved the maximum score for a healthy, diverse diet.
Writing in the latest Australian and New Zealand Journal of Public Health, researchers said almost half of the children ate less than 30g of meat or an alternative on the survey day and most had egg, chicken or ham, which had less iron than red meat.
Almost all had foods considered completely unnecessary at their age, such as sweet biscuits.
One in five ate sugary biscuits, consistent with a study of Perth children which found 92 per cent had eaten biscuits or cakes by 12 months of age.
Researchers found a third of children ate "the quintessential Australian food" Vegemite but its flavour could trigger an innate preference for salt. "Parents may be advised to use this spread sparingly and not offer it to children every day," they wrote.
The study warned a healthy diet from infancy was needed to prevent childhood obesity and the onset of chronic disease.
Lead researcher Rebecca Byrne, from Queensland University of Technology, said childhood obesity had doubled in Australia since 1986, with about 21 per cent of children aged two to three overweight or obese.
"The toddler years are a critical age in the development of long-term food preferences but this is also the age that autonomy, independence and food fussiness begins," Ms Byrne said.
"A nutrient-dense diet that incorporates all five food groups is important, as evidence suggests that food preferences develop at this early age and persist into adulthood."
Iron deficiency remained an issue for toddlers.