Mikhaila and Scarlett Peterson
Canadian Mikhaila Peterson shares more than DNA and a depressive tendency with her famous father, Dr Jordan Peterson, the Toronto University psychology professor, author of the best-selling 12 Rules For Life: An Antidote for Chaos and self-proclaimed "professor against political correctness".

Father and daughter have also become global poster children for the benefits of a carnivorous diet. Both credit it with reversing all symptoms of debilitating autoimmune illnesses and depression that plagued them for decades.

A wholly carnivorous diet is on the extreme end of the low-carbohydrate, high-fat (LCHF) spectrum. It is also a "ketogenic" diet, in which the body turns fat into ketone bodies to use for fuel, instead of glucose.

LCHF diets are controversial, despite growing evidence of their benefits for treating and preventing chronic diseases. Carnivorous diets are even more controversial. Some doctors and dietitians tell patients that these diets are "extreme" and dangerous. Others say traditional societies, such as the Inuit of Canada and the Masai of Kenya, and robust research show that carnivorous diets are safe, natural and healthy.

Mikhaila Jordan's auto-immune diseases were life-threatening. At age seven, doctors diagnosed severe rheumatoid arthritis that left her in chronic pain and affected most of her joints. By 17, she had multiple joint replacements.

Her father no longer has digestive issues, mild psoriasis (an auto-immune skin condition), mouth ulcers, fatigue, depression or difficulty maintaining a healthy weight. Both are off all medication.

Mikhaila, 26, describes herself as a "very sickly child".

From the age of two, she was prone to bacterial and viral infections (strep throat, colds and respiratory problems) as well as yeast infections.

When she was 10 years old, doctors diagnosed severe depression, anxiety and occasional hypomania, a mild form of mania marked by elation and hyperactivity. They prescribed more drugs. "Antidepressants were a godsend," she says.

Doctors also diagnosed idiopathic hypersomnia, a form of narcolepsy. She spent about 17 hours a day sleeping.

She downed a cocktail of drugs daily: antidepressants, methotrexate (an anticancer drug), opioid-derived pain-killers, immune suppressants and stimulants to keep her awake. They alleviated some symptoms but caused others.

In her early teens, Mikhaila's skin started itching. She developed cystic acnes - blistering, painful bumps that would not heal.

In December 2014, she consulted doctors, who either had no idea what was wrong or said she was just overanxious - her problems were psychosomatic. "Blame the patient, thanks," she says ruefully.

When chronic sores appeared on her face, vanity kicked in and drove her to start experimenting with diet. An even more defining moment was the sudden death of a 30-year-old distant cousin of her father in 2015. The cousin had skin problems that wouldn't heal and doctors had no idea what had caused her death.

Mikhaila says she felt terrified she would die too. "I'm on 15 medications to wake up in the morning. If I don't figure out what the hell is wrong, I'm going to die," she recalls thinking.

She read up on nutrition science and changed her diet. In September 2015 she began an elimination LCHF diet, eating only chicken, beef, fish, rice, sweet potatoes, carrots, spinach and salad greens, with coconut, olive oil, apple cider vinegar and spices. Within a month, her health improved, her skin healed and arthritis symptoms reduced. Fatigue and depression, however, continued.

After she became pregnant with daughter Scarlett, born in August 2017, Mikhaila ate LCHF throughout her pregnancy. "No cheating, ever," she says.

After Scarlett's birth, she began researching ketogenic diets and went carnivorous. She now eats about 1.5kg of meat a day, mostly ribeye steak. She also drinks lots of water.

The results have been "amazing", she says.

"It's like I woke up. It was disturbing, realising I could have prevented all my horrible diseases with diet," Mikhaila says. She credits her father with giving her the resilience needed to survive. In his book and public talks, he speaks philosophically of the common "burden of suffering" and taking responsibility for one's life.

He taught her to accept the burden, take responsibility and not see herself as a victim.

Jordan no longer has digestive issues, mild psoriasis, mouth ulcers, fatigue, depression or difficulty maintaining a healthy weight. Both father and daughter are off all medication.

Despite this, many health experts still believe the pair are doing themselves more harm than good.

The Association for Dietetics in SA leadership is critical of LCHF and carnivorous diets. On its website, the association says "especially in the extreme form", LCHF diets "do not align" with SA's official dietary guidelines for high-carb, low-fat diets.

It claims "a lack of conclusive evidence" for health benefits of LCHF diets long term. These diets emphasise "an increased intake of animal [saturated] fat" that may present "a real risk for heart disease" and are likely to cause nutrient deficiencies.

The association also says because LCHF diet are costly, most South Africans can't afford them and this will "worsen food security, especially in resource-scarce settings". It claims LCHF diets "pose a significant threat to environmental sustainability".

US surgeon, carnivore and elite athlete Dr Shawn Baker vehemently disagrees. His mother was born in Benoni and he spent time in SA as a child. "I remember how much I enjoyed the biltong," he says.

Critics of animal food-based diets depend largely on epidemiology, Baker says, which is "fraught with confounding data and is largely meaningless with regard to being able to draw any conclusions".

Stanford University professor of medicine Dr John Ioannidis is more scathing. He has called nutritional epidemiology "a scandal" that should "just go to the waste bin".

The few randomised controlled trials on meat and saturated fats do not demonstrate negative effects, Baker says. Animal studies are "limited in ability to demonstrate causation of disease applicable to humans", he says.

Daily, he sees patients putting diseases such as rheumatoid arthritis, Crohn's, psoriasis and depression into remission on low-carb, ketogenic and meat-only diets. Osteoarthritis commonly disappears while digestion improves.

"Commonly, high blood pressure returns to normal and insulin levels fall as we see evidence of inflammation disappearing both clinically and in laboratory studies."

Many people, including athletes, lose weight and put on muscle after adopting LCHF carnivorous diets, he says.

Among these is All Blacks rugby star Owen Franks, who has stated that he is becoming bigger, leaner and stronger than he has been yet. "Watch out, Boks," Baker warns.

In his practice, he started cancelling surgeries as his patients' pain disappeared on LCHF. That brought him into conflict with his hospital administration, creating a 30-month battle that is close to resolving.

Baker started on a low-carb, ketogenic diet after studying older and historical scientific observations about meat and physical performance. He noticed improvements in his body composition and health but still had minor issues - tendon and joint pain.

He accepted these as a normal consequence of ageing and being a high-level athlete.

In late 2016, he did a full 30-day carnivorous trial to test for improvements to his athletic performance. He felt good on it and all residual joint aches and pains vanished.

"I was pretty shocked by that and, after a brief period where I returned to my usual ketogenic diet, the joint pain returned," Baker says. He went back onto a carnivorous diet.

US science journalist Nina Teicholz documents research for a carnivorous diet in her best-selling book The Big Fat Surprise: Why Butter, Meat and Cheese Belong in a Healthy Diet. It's a seminal work that has ruffled medical and dietetic establishment feathers and shaken nutrition science foundations.

The American Journal of Clinical Nutrition called it a "historical treatise on scientific belief versus evidence" and an "example of how limited science can become federal policy".

Teicholz presents a 1928 experiment that Icelandic explorer and ethnologist Vilhjalmur Stefansson and a fellow explorer conducted. They locked themselves up in a hospital for 12 months, subjected themselves to a carefully monitored laboratory environment and ate nothing but meat.

Doctors expected both to die. Both survived and thrived.

The Noakes Foundation says its Eat Better SA outreach programme proves that LCHF diets don't have to be expensive.