A Sydney naturopath has been sentenced to seven months in prison for her role in starving an infant in 2015, after a judge slammed her extreme diet advice that almost killed the eight-month-old.

Marilyn Pauline Bodnar was sentenced to a maximum of 14 months' jail but will be eligible for parole on November 4.

The 62-year-old pleaded guilty to an accessory charge of causing danger of death to a child, when she advised the boy's mother to adhere to a strict diet of raw vegetables, fruit, and seeds.

The mother, who cannot be identified for legal reasons, had sought advice from Bodnar on how to treat the boy's eczema.

The Downing Centre District Court heard Bodnar advised the woman that the skin condition was caused by the mother's diet and toxins, and she urged her to consume only water and watermelon for three days after the boy began suffering from fever.

Judge Peter Berman said Bodnar's actions were "seriously criminal" and he considered public deterrence in handing down his sentence.

"Well intentioned but seriously misguided advice is … capable of causing great harm and even death to vulnerable children," Judge Berman said.

"There is no doubt that she is a caring and well-meaning individual and that her intentions in providing advice to [the child's] mother were based on what she believed to be some connection between [his] eczema and the mother's diet.

"But once it became clearly apparent that there was a risk of harm to [the child] through the mother following her advice, it was a seriously criminal thing to do to ignore the effect of her advice on [the child's] wellbeing."

The court heard Bodnar saw the child three times between February and May 2015.

The young boy was "just days" from death, according to police, when he was eventually taken to Westmead Children's Hospital on May 28, 2015, suffering from severe malnourishment and developmental issues.

In his submissions, Bodnar's lawyer Rick Mitry said his client had expressed her deepest remorse and had "been punished since the very beginning of this saga".

"Her arrest was almost a staged affair," Mr Mitry told the court, but Judge Berman rejected his assessment, responding that there was "no evidence of that".

Mr Mitry said his client had promised never again to work with children and had a strong chance of rehabilitation.

Mr Mitry said he would take instructions from his client as to whether she would appeal the decision.

Outside court Bodnar's husband, Cecil Bodnar, said the sentence was "devastating" and the couple would be seeking legal advice about whether to appeal.

He said the case had been "very taxing on her, she's suffered a lot".

"She's had terrible phone calls from weird people in the public," he said, adding that throughout the whole court process people had only heard one side of the story.