Chef Pete Evans is in dispute with the Heart Foundation and the Dietitians Association of Australia (DAA) over the merits of the Paleo diet.
Evans has described himself as a "warrior", whose "life's purpose" is to promote the Paleo, also known as the "caveman", diet.
The controversial diet is designed to emulate only what humans are thought to have eaten during the Paleolithic era. It promotes poultry, fish, eggs, fruit, vegetables and meat, and avoids legumes, grains and dairy products.
Over the weekend, the host of My Kitchen Rules launched a sustained attack on the "fearmongering" of the two organisations for their warnings of the dangers of the diet.
"You all have ignited a spark that has been inside me, which is now a raging fire in my belly ... the warrior in me is now ready for what's next," he wrote on his Facebook page.
"At times in my life I haven't been focused or very clear of my lifes purpose, however I have a laser focus for what I want to achieve whilst I am on this journey in this body."
It is the latest in a series of impassioned posts that Evans has fired off in defence of the diet.
Evans has recently graduated as a health coach from the Institute for Integrative Nutrition in New York.
His impassioned defence of the diet is in contrast with the institute's bio-individuality theory.
"Our curriculum teaches bio-individuality, or that one person's food is another person's poison, because no one diet is right for everyone," a statement from the institute's founder Joshua Rosenthal explains on its website.
"One of the major factors shaping bio-individuality is ancestry.
"If many generations of your ancestors from Scandinavia were accustomed to eating dairy on a daily basis, it's natural that your body will be able to assimilate dairy foods."
In targeting the DAA and the Heart Foundation, Evans claims that the Paleo diet is the most natural approach to healthy eating.
"How can this organisation [DAA] publicly attack a way of life that is helping families reclaim their health in the most natural way possible?" he asked.
The chef has recently written a Paleo cookbook.
He did not miss an opportunity to promote on Facebook one of his latest Paleo recipes, "the chakra salad" with fermented vegetables, nuts, bacon dressing, eggs and avocado.
"Please share this recipe amongst your tribe as it is so yummy and a great one to mix together," he said.
The Heart Foundation claims the Paleo diet is putting heart health at risk.
"We know that the high level of saturated fat in a diet increases the risk of heart disease," a Heart Foundation spokeswoman said.
The Heart Foundation and the DAA have historically kept their distance from diets such as Paleo and Atkins.
They claim a balanced diet that mixes all food groups is the best approach to healthy living.
"Any diet excluding whole food groups should raise suspicions," the DAA's chief executive officer, Claire Hewat, said a statement in July.
"The idea of cutting out grain-based foods and legumes is not backed by science and eating more meat than is needed by the body certainly has risks, according to the World Health Organisation."
A DAA spokeswoman said in a statement on Tuesday: "Outspoken advocates of the Paleo diet have criticised the Dietitians Association of Australia and its members for questioning the merits of the Paleo diet.
"Our members work hard to make a real difference in people's lives by helping and supporting them to eat better food and be healthier, or working on policy and product development to improve the food supply.
"Our primary concern is that some aspects of the Paleo diet are inconsistent with the Commonwealth Department of Health's 'Australian Dietary Guidelines'.
"When it comes to diet and health there is no one-size-fits-all or magic bullet approach. DAA encourages Australians to take a longer-term view to health, based on the recommendations of the Australian Dietary Guidelines."
The Heart Foundation has been approached for comment.
