Sydney couple in court after strict vegan diet leaves toddler malnourished

A Sydney couple face five years in prison for neglecting their 20-month-old daughter by putting her on a strict vegan diet.

The unnamed child was admitted to Sydney Children's Hospital after suffering a seizure in March last year.

In a victim impact statement to the Downing Centre Court in Sydney, the baby's foster carer said the toddler weighed just 4.89kg, reports.

The couple, in their early 30s, appeared in court on Thursday. They are charged with failing to provide for a child, causing danger or serious injury, and reckless grievous bodily harm.

Investigators say when the toddler was admitted to hospital her body was so malnourished she resembled a three-month-old baby.

The girl had urgent treatment and remained under medical care for three weeks.

Judge Sarah Huggett told the court it should have been known by the father that something was not right, due to the fact he was an "educated man", reports.

"She wasn't walking or talking, she wasn't hitting milestones," she said.

"He did nothing. He could have picked her up and taken her to a doctor. He is older than the mother and could have just as easily have done something."