Richard Mackarness

Guy Richard Godfrey Mackarness (17 August 1916 - 18 March 1996) was a British physician 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.


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 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 was a founding member of the Clinical Ecology Group, which later became the British Society for Allergy and Environmental Medicine. He also founded the Chemical Victims Association.

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

Stone Age Diet

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 grain and sugar. The book was a success and sold over 1.5 million copies.

Physiologist Ancel Keys criticized Eat Fat and Grow Slim and commented that it "offers no scientific evidence, but the cartoons of imaginary biochemical processes are amusing, though they have nothing to do with scientific reality."

Selected publications

  • Eat Fat and Grow Slim: Or, Banting Up to Date (1958)
  • Stone Age Diet for Functional Disorders (1959)
  • Eating Dangerously: The Hazards of Allergies (1976)
  • Not All in the Mind (1976)
  • Chemical Victims (1980)
  • A Little of What You Fancy: How to Control Smoking and Other Cravings (1985)
  • Chemical Allergies (1990)

    Further reading

  • David Gentilcore; Matthew Smith. (2018). [ Allergic to Innovation? Dietary Change and Debate about Food Allergy in the United States]. In Proteins, Pathologies and Politics: Dietary Innovation and Disease from the Nineteenth Century. Bloomsbury Academic.