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Eat Fat, Get Thin

Mark Hyman

New York, Little, Brown and Company, 2016, 386 pp., $28

Mark Hyman, MD, trained in family medicine and is a major figure in the emerging area called functional medicine. He is chair and director of the Cleveland Clinic Center for Functional Medicine and is chairman of the Institute for Functional Medicine. Of his previous 16 books, the most noteworthy is The Blood Sugar Solution (2012).1 With Eat Fat, Get Thin, Hyman presents a more positive message about what to eat (healthy fats) rather than emphasizing what not to eat (high glycemic carbohydrates).

Hyman joins a growing list of physician authors putting to rest the mistaken recommendation made over 4 decades to eat a low fat diet.2-4 Not all fats are healthy, and some are toxic, such as the trans fats in processed foods. The content of the book can be predicted by the cover containing an avocado, tree nuts, olive oil, and some dark chocolate.

Hyman details how excess body fat comes mainly from the ingestion of high amounts of carbohydrates.1-4 Carbohydrates cause the release of insulin that results in blood sugar fluctuations that drive hunger. Excess carbohydrates are converted to fat in the liver through lipogenesis.

Some interesting facts are presented here. The Joslin Diabetes Center at Harvard was named after Dr Elliott P. Joslin, who in the 1920s recommended a diet of 75% fat, 20% protein, and 5% carbohydrates to treat diabetes. After fat became demonized starting in the 1950s, the carbohydrate recommendation went up to 60%. Hyman reports that currently researchers at the Joslin Diabetes Center are once again recommending a diet high in fat, up to 70%, for the treatment of type 2 diabetes.5

The strength of this book is an extensive analysis of what constitutes healthy fats, mostly from plant sources. Hyman gives a detailed explanation as to why he thinks that some fats from animal sources, eggs, grass-fed beef or free range poultry, and wild caught fish, are important for healthy nutrition. He promotes what he calls the “Pegan Diet,” mostly Vegan but some amount of healthy Paleo foods.

I find that patients like this book recommendation because of its positive title and message. Students and residents will find it an informative and entertaining read and will be helped in changing away from the paradigm of low fat foods. All of the information is sound and well referenced. For a more in-depth scientific analysis of why we should avoid high glycemic carbohydrates, I recommend Harvard’s David Ludwig and his recently published book Always Hungry? (2016).6

Joseph E. Scherger, MD, MPH

Eisenhower Medical Center

Rancho Mirage, CA



  1. Hyman M. The blood sugar solution. New York: Little, Brown and Co., 2012.
  2. Perlmuter D, Loberg K. Grain brain. New York: Little, Brown and Co., 2013.
  3. Mullen G. The gut balance revolution. New York: Rodale, 2015.
  4. Wahls T. The Wahls protocol. New York: Avery (Penguin Group), 2014.
  5. Hamdy O. Nutrition revolution—the end of the high carbohydrates era for diabetes prevention and management. US Endocrinol 2014;10(2):103-4.
  6. Ludwig D. Always hungry? New York: Hachette Book Group, 2016.

Copyright 2018 by Society of Teachers of Family Medicine