A controversial academic study has reignited debate over whether red and processed meat cause cancer and heart disease, with researchers recommending people keep eating the same amount of meat.

Key points: Nutritional guidelines say we should only eat 455 grams of lean, cooked red meat each week

Nutritional guidelines say we should only eat 455 grams of lean, cooked red meat each week The latest figures show Australians consume around 560g a week

The latest figures show Australians consume around 560g a week Health authorities say the study will only confuse people, who should be eating healthier

Led by Dalhousie University and McMaster University in Canada and published in the Annals of Internal Medicine, the findings have infuriated health professionals around the world who warn the report could pose a risk to public health.

The most controversial finding — that the risks of eating red meat are minimal, and that the evidence is too weak to prove the risks are real — go against the advice of health bodies around the world, including the World Health Organisation (WHO).

"We're not saying there is no risk. We're saying there is only low-certainty evidence of a very small reduction of cancer and other adverse health consequences of reducing red meat consumption," one of the researchers, Associate Professor Bradley Johnston, told the BBC.

"The right choice for the majority of people, but not everyone, is to continue their meat consumption."

WHO's International Agency for Research on Cancer (IARC) made global headlines in 2015 when it found processed meat was "carcinogenic to humans" and that eating red meat was "probably carcinogenic".

The review's findings were compiled by 14 researchers in seven countries over three years. Researchers involved were vetted for conflicts of interest, and the review did not have any external funding.

McMaster University said the team of researchers reviewed randomised controlled trials and observational studies looking at the impact of red meat and processed meat consumption on cardiometabolic and cancer outcomes.

"In one review of 12 trials with 54,000 people, the researchers did not find statistically significant or an important association between meat consumption and the risk of heart disease, diabetes or cancer," the university reported.

Health authorities say they new report may confuse people. ( ABC News: David Fraser )

Findings at odds with Australian dietary suggestions

The new review contradicts Australia's nutritional guidelines, which recommend Australians eat the equivalent of about three average-sized serves of lean, cooked red meat per week (455 grams).

That recommendation is lower than what the average Australian currently consumes — around 560g — according to the most recent official data from 2013.

Australia's nutritional guidelines also suggest reducing the intake of processed meats, which can be high in salt and saturated fats.

According to Cancer Australia, "there is convincing evidence that consumption of processed meat and red meat increases the risk of colorectal cancer, and there is also suggestive evidence of an increased risk of oesophageal, lung, pancreatic and stomach cancers".

Dr Johnston said he acknowledged the review findings were contrary to current scientific consensus and many nutritional guidelines, but defended the work nonetheless.

"This is not just another study on red and processed meat, but a series of high quality systematic reviews resulting in recommendations we think are far more transparent, robust and reliable," he said.

However, that did not stop Harvard University's TH Chan School of Medicine labelling the reports "irresponsible and unethical" and warned it sent confusing messages to consumers.

"It may also harm the credibility of nutrition science and erode public trust in scientific research," the school said.

"In addition, it may lead to further misuse of systematic reviews and meta-analyses, which could ultimately result in further confusion among the general public and health professionals."

Some in the scientific community are concerned the study could be used when countries or territories develop or update their nutritional guidelines, however British health officials have already ruled this out according to the BBC.

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Professor Clare Collins, director of research in the School of Health Sciences at The University of Newcastle, said it was unlikely the findings would prompt a change to any dietary guidelines.

"The authors have not presented evidence that national dietary guidelines need updating. Poor eating habits are the leading cause of death worldwide. This report will confuse the public," she said.

"When you look past the headline, all the papers indicate that higher intakes of processed and red meat are associated with a higher risk for all-cause mortality, heart disease, type 2 diabetes, and some cancers.

"You have to question the recommendations made given that the data presented in the papers does not support it."

Interestingly, the researchers themselves said the findings were unlikely to sway the decision of meat eaters.

"Omnivores are attached to meat and are unwilling to change this behaviour when faced with potentially undesirable health effects," the authors said.

Livestock sector welcomes report

Australia's red meat sector, which in recent years has become heavily targeted by animal rights activists, has welcomed the findings.

"I think any supporting scientific evidence that outlines why the consumption of red meat — a staple protein supply for humans for thousands of years — is in fact good for you [is a positive]," Don Mackay, chairman of the Red Meat Advisory Council, said.

"There's little doubt there are plenty of people, individuals, and organisations who would seek to have red meat consumption reduced.

"So this report supports our industry and appropriately so."