The roots of the paleolithic ketogenic diet date back nearly 90 years, with an Arctic traveller who had a theory about an all-meat diet.
The traveller’s name was Vilhjalmur Stefansso, an anthropologist who was convinced that the Arctic Inuit’s fat and meat-based diet was not only healthy, but held significance for future dietary research.
Stefansson reported that the Inuit diet consisted of roughly 90 per cent meat and fish, with little carbohydrate He believed that if he too adopted the diet, he would not have any health problems.
A trip to the Arctic
Stefansson travelled to the Arctic a number of times with a team of explorers in the early 1900s and found that living off the land led to no adverse reactions. They bought their findings back to the US, and Stefansson agreed to a new trial.
This time the trial was a controlled experiment into the effects of an all-meat diet on the body, led by US researchers Walter S. McClellan and Eugene F. Du Bois. 
The year-long trial began in 1928 at Bellevue Hospital New York, where Stefansson and colleague Dr. Karsten Anderson eliminated all plant foods including starchy and sugary carbohydrates from their diet. Around 80 per cent of their diet was animal fat; 20 per cent from protein. No vitamins or mineral supplements were allowed.
Stefansson discovered he felt much better on the diet when carbs were restricted, yet experienced some problems when fat was controlled.
Neither Stefansson nor Anderson experienced any signs of kidney problems or symptoms of vitamin deficiency, and both remained healthy during the study.
Throughout the 20th Century, evolving research brought the ketogenic and paleo diets to scientists’ attention.
The ketogenic diet is a high-fat, moderate-protein, low-carbohydrate diet which was shown to be able to treat epilepsy in the 1920s. However, it was largely shelved as a subject of dietary research until the 1970s.
When a researcher called Peter Huttenlocher devised a ketogenic diet where 60 per cent of the calories came from MCT oil, this allowed people to consume more protein and carbohydrates, enabling greater flexibility with meal planning.  However, an MCT diet is associated with gastrointestinal side effects. This limited its feasibility and prevented the diet from becoming widely used.
The paleo diet
The origins of the paleo diet can be traced back to 1975 when gastroenterologist Walter L. Voegtlin published a book advocating the Stone Age diet, based mainly on foods presumed to have been available to humans living in the Paleolithic era.
The theory was popularised by American Scientist Loren Cordain in his 2002 book The Paleo Diet. Cordain developed his approach based on lean meat, fish, fruits and vegetables.
Another pioneer of the paleo field is Staffan Lindeberg. He is best known for the Kitava study in which he described diet and health of the people living on the Kitava Island, Papua New Guinea, with a traditional, non-westernized diet. He found no single man or woman with any chronic diseases of civilization on the island. 
Hungary for change
The paleo diet became a popular field of research in Hungary around 2010. Hungarian physicians Dr Csaba Tóth and Dr Zsófia Clemens, from Paleomedicina Hungary, argue this is partly because of Hungary’s poor healthcare system, and the diet was a means of combating medication requirements.
Consequently, researchers attempted to integrate the paleo approach into medicine, but the findings indicated the approach needed to be refined.
“We started using the paleo diet, but the results weren’t perfect,” said Tóth. “It’s good for treating high blood sugar levels and high blood pressure, but it’s not effective for autoimmune diseases.
“So we started using the paleolithic ketogenic diet, which combines the advantages of the paleo and the classic ketogenic diet while overcoming the shortfalls of both diets, resulting in a very effective diet.”
One of the main differences between the paleo diet and the paleo keto diet is that the latter excludes some foods included in the paleo diet, such as vegetable oils and restricts plant based food to help ensure ketosis. This, Tóth says, is what makes the paleo keto diet more effective for health than either the paleo or keto diet separately.