A Tasmanian surgeon who was told by the nation's medical watchdog to stop giving specific nutritional advice is one of several cases that prompted a Senate committee to call for an inquiry into the agency.

Key points: Dr Gary Fettke reprimanded by medical watchdog AHPRA for suggesting patients eat low-carb diets

Dr Gary Fettke reprimanded by medical watchdog AHPRA for suggesting patients eat low-carb diets AHPRA found he was not qualified to give nutritional advice

AHPRA found he was not qualified to give nutritional advice His case has prompted a Senate committee to call for inquiry into AHPRA

Gary Fettke is an orthopaedic surgeon and an advocate of a low carbohydrate diet.

He said he became passionate about nutrition after amputating limbs of diabetic patients whose diets were a big part of the problem.

"What I've been advocating for some years is cutting sugar down, particularly all the refined sugars in the diet," he said.

"Over time that's evolved, and it's evolved to what I call low carb, healthy fat.

"It's just eating lots of vegetables, pasture-fed meat and the right amount of oil in the form of things like nuts, avocado, cheese, olive oil and fish."

One of his patients, Julian Robinson, who had to have his leg amputated because of complications from diabetes, said the diet changed his life for the better.

"He virtually said to me, 'You need to change your diet and your lifestyle or you'll die,'" Mr Robinson said.

"I cut out of my diet most of the carbohydrates, which was hard because I like biscuits so much, and increased my protein. I eat a lot more meat and eggs."

A recent study by the CSIRO has found a low carbohydrate diet had better outcomes for diabetics.

While dieticians do prescribe it, many say it should not be used for everyone.

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Anonymous complaint sparked investigation

Doctor Fettke started pushing for changes to the food in the Launceston General Hospital where he worked and then criticised the hospital for a lack of action.

According to Dr Fettke, an anonymous complaint from a dietician at the hospital sparked an investigation by the Australian Health Practitioner Regulation Agency (AHPRA).

Two and a half years later the watchdog found he was working outside his scope of practise and was not qualified to give specific nutritional advice, and he was ordered to stop speaking about the low carbohydrate, high fat diet.

"The committee does not accept that your medicine studies of themselves provide sufficient education or training to justify you providing specific advice or recommendations to patients or the public about nutrition and diet, such as the LCHF lifestyle concept," it read.

Dr Fettke said the findings could have repercussions for other health professionals.

"I've been contacted by many doctors. I know the AMA has been contacted by many doctors as well as the medical protection society.

"And it's not just for doctors, it's for nurses who are working in outreach areas, even nurses in the community, dentists, pharmacists, chiropractors. You go to your cardiologist and he tells you what to eat, you go to a neurosurgeon and he tells you what to eat, gastroenterologist and all of them, by definition, don't have a major training in nutrition and yet they're all giving advice."

Dr Gary Fettke began offering dietary advice after amputating limbs of diabetic patients. ( ABC News: Natalie Whiting )

Concerns about doctor's online posts

The AHPRA investigation also raised concerns about things he was posting on his website and social media accounts, saying his posts online may be misinterpreted by people who might conclude reducing sugar could slow or cure cancer.

"Never have I said that it's an alternative to the treatment of radiotherapy, surgery and chemotherapy. Very specifically we need to be thinking about our nutrition as an adjunctive therapy to the current ones," he said.

"In my situation there's been never a case of patient harm, not a patient complaining, and that's what I see as the farcical thing."

The AHPRA investigation also raised concerns that Dr Fettke had pushed patients into the diet, an accusation he denies.

"You cannot push a way of eating onto a person. All I've ever done is told patients that there is a choice, that there is an option that's out there."

AHPRA cannot comment on the case unless Dr Fettke gives them permission, which he won't because of legal advice he has received.

However AHPRA has released a statement reaffirming that it expects medical practitioners to provide appropriate dietary advice to patients.

Senate committee recommends inquiry

AHPRA itself is now in the spotlight. Prompted by Dr Fettke's case, a Senate committee has recommended a new inquiry be held into AHPRA, the complaints process and whether changes are needed.

Tasmanian Greens senator Peter Whish-Wilson sat on the initial inquiry.

"What the committee found was that to a lot of practitioners, the AHPRA process itself, the investigative process, the notifications process is being perceived to be bullying and intimidation as well," Senator Whish-Wilson said.

He said he was concerned Dr Fettke's investigation was the result of a vexatious complaint.

AHPRA said it believes vexatious complaints are a small problem but it is commissioning research into the area.

The inquiry has also lead to calls for cautions issued by the watchdog, like the one Dr Fettke received, to be appealable.

At the moment the only option is a Supreme Court challenge over the process, something Dr Fettke is considering.

"The process is really the thing that's up for question at this point in time. Not just for me, but for multiple practitioners in the health system. It goes on and on and on," Dr Fettke said.

"You are guilty until proven otherwise."