Richard Mackarness

He married Margaret Perry-Walker in 1947. They had a son, Patrick. Mackarness died of a stroke on 18 March 1996 in Mornington, Australia.

Mackarness authored Not All in the Mind in 1976, which argued that common foods such as coffee, eggs, milk and white flour may make people mentally and physically ill. He recommended his Stone Age diet in the book and stated that humans have not evolved to consume foods from the rise of agriculture such as milk and wheat resulting in hidden food allergies that can cause chronic health problems.

Mackarness was born in Murree, India. He received his education from Lancing College and the Westminster Teaching Hospital. He later left general practice to become an assistant psychiatrist at Park Prewett Hospital, Basingstoke (1965–1981). Mackarness was an advocate of clinical ecology and was influenced by the research of Theron Randolph on food allergies. He developed a controversial environmental approach to psychiatric disease. His ideas were not accepted by the medical community.

Mackarness authored the book Eat Fat and Grow Slim (1958), which exposed what he termed the "calorie fallacy" and proposed a low-carbohydrate "Stone Age" diet of fat and protein. He took influence from the ideas of William Banting. His Stone Age diet was influenced by the habits of Stone Age people with an emphasis on fish, meat, simple vegetables and roots. Mackarness opposed the consumption of cow's milk, grain, soy and sugar. The book was a success and sold over 1.5 million copies.

In the book Mackarness listed four doctors who had used a Stone Age type diet to treat their patients. Mackarness had personally met these doctors in 1958 and termed them "anti-cereal doctors". They were; Ray Lawson a surgeon from Montreal, Alfred W. Pennington of New Jersey, George L. Thorpe of Wichita and Blake F. Donaldson of New York.

Mackarness met Theron Randolph in the 1950s and applied his methods to treat patients with mental illness at Basingstoke Hospital. In 1979, Mackarness was described as "Britain's foremost champion of clinical ecology." He believed that most patients with psychiatric problems can trace their symptoms to an allergy. He treated patients at Basingstoke Hospital for food and chemical allergies mostly on an outpatient basis.

Guy Richard Godfrey Mackarness (17 August 1916 – 18 March 1996) was a British psychiatrist and low-carbohydrate diet writer. He is best known for his book Eat Fat and Grow Slim, published in 1958. Mackarness was an early advocate of the Paleolithic diet and authored books on food allergies.