Jason Fung

Jason Fung (born in 1973) is a Canadian nephrologist and low-carbohydrate diet advocate who promotes intermittent and extended fasting.

Biography

Fung graduated with his medical degree from the University of Toronto and completed his residency and fellowship in nephrology at the University of California, Los Angeles.[1][2]

Fung is an author of books advocating fasting and low-carbohydrate high-fat diets.[3][4][5] His first book, The Complete Guide to Fasting co-authored by Jimmy Moore was published in 2016 and offered insight to all aspects of fasting culture.[6] The Obesity Code and The Diabetes Code were subsequently published in 2016 and 2018.[7][8] His book The Obesity Code Cookbook was published in 2019.[9] In 2020, Fung co-authored with naturopath Nadia Brito Pateguana The PCOS Plan: Prevent and Reverse Polycystic Ovary Syndrome Through Diet and Fasting.[10] His book The Cancer Code, published in 2020 advocates intermittent fasting and a low-carbohydrate diet to reduce cancer risk.[11] In 2021, Fung co-authored The Diabetes Code Cookbook with Alison Maclean.[12] Fung has suggested that there is "nothing wrong" with fasts of up to a month.[13]

Fung is the director of the non-profit organization Public Health Collaboration.[14] He is an advocate of functional medicine.[14]

Reception

Renza Scibilia in Clinical Diabetes commented that Fung's belief that all the current evidence-based, conventional treatments are wrong for type 2 diabetes is an untrue assertion but his dietary management solution to treat diabetes is very clear.[3] This includes type 2 diabetics removing fructose, processed foods and sugar-sweetened beverages from their diet whilst increasing natural fats.[3]

Fung's book The Obesity Code received a 31% score for scientific accuracy and an overall score of 60% by Red Pen Reviews.[7] Reviewer Seth Yoder commented that several of the main claims of the book are poorly supported by science including the idea that elevated levels of insulin are the primary cause of obesity. Yoder concluded that intermittent fasting may be useful for weight loss, "but most people will not find it as effective as claimed in the book".[7]

Fung's book The Diabetes Code received a 33% score for scientific accuracy at Red Pen Reviews. Reviewer Shaun Ward commented that the benefits of a low-carbohydrate and harms of sugar and medication were overstated by Fung and that although the dietary advice may be effective for managing type 2 diabetes it is unlikely to be sustainable for most people.[4]

Publications

Books

  • The Complete Guide to Fasting (2016)
  • The Obesity Code (2016)
  • The Diabetes Code (2018)
  • The Obesity Code Cookbook (2019)
  • The Longevity Solution (2019)
  • The PCOS Plan: Prevent and Reverse Polycystic Ovary Syndrome Through Diet and Fasting (2020)
  • The Cancer Code (2020)
  • Life in the Fasting Lane (2020)
  • The Diabetes Code Cookbook (2021)[15]

Academic papers

  • Therapeutic fasting as a potential effective treatment for type 2 diabetes: A 4-month case study.[16]
  • Hyperinsulinemia and Insulin Resistance: Scope of the Problem.[17]
  • Therapeutic use of intermittent fasting for people with type 2 diabetes as an alternative to insulin.[18]

References

  1. ^ "Dr. Jason Fung, MD". Diet Doctor. 2025. Archived from the original on March 7, 2025.
  2. ^ "BBC Science Focus Magazine - Dr Jason Fung". www.sciencefocus.com. Retrieved April 26, 2025.
  3. ^ a b c Scibilia, Renza (2019). "The Diabetes Code: Prevent and Reverse Type 2 Diabetes Naturally". Clinical Diabetes. 37 (3): 302–303. doi:10.2337/cd19-0025. PMC 6640893. PMID 31371867.
  4. ^ a b Ward, Shaun (2024). "The Diabetes Code: Prevent and Reverse Type 2 Diabetes Naturally". Red Pen Reviews. Archived from the original on January 20, 2025.
  5. ^ Bowyer, Jerry. "Is Fasting The Cure For Bloated Healthcare Costs?". Forbes.
  6. ^ "Complete Guide To Fasting: Heal Your Body Through Intermittent, Alternate-day, And Extended Fasting". indigo.ca. 2022. Archived from the original on February 10, 2022.
  7. ^ a b c Yoder, Seth (2019). "The Obesity Code: Unlocking the Secrets of Weight Loss". Red Pen Reviews. Archived from the original on October 24, 2022.
  8. ^ Scherger, Joseph E. (2019). "The Diabetes Code". Fam Med. 51 (3): 286–287. doi:10.22454/FamMed.2019.998853. S2CID 76663782.
  9. ^ "International: 30 bestselling books for the week of Dec. 21". vancouversun.
  10. ^ "The PCOS Plan: Prevent and Reverse Polycystic Ovary Syndrome through Diet and Fasting". indigo.ca.
  11. ^ Fung, Dr Jason (November 10, 2020). The Cancer Code by Dr. Jason Fung. HarperCollins Publishers. ISBN 9780062894007. Archived from the original on November 29, 2022 – via www.harperwave.com.
  12. ^ "The Diabetes Code Cookbook". Greystone Books. 2021. Archived from the original on December 13, 2024.
  13. ^ "One Month Without Food". The Atlantic. November 21, 2016.
  14. ^ a b "Jason Fung, MD". The Institute for Functional Medicine. 2024. Archived from the original on September 17, 2024.
  15. ^ "Books by Jason Fung (Author of The Obesity Code)". www.goodreads.com. Retrieved April 26, 2025.
  16. ^ Ku, Michael; Ramos, Megan J.; Fung, Jason (December 15, 2017). "Therapeutic fasting as a potential effective treatment for type 2 diabetes: A 4-month case study". Journal of Metabolic Health. 2 (1): 5. doi:10.4102/jir.v2i1.31. ISSN 2960-0391.
  17. ^ Fung, Jason; Berger, Amy (December 3, 2016). "Hyperinsulinemia and Insulin Resistance: Scope of the Problem". Journal of Metabolic Health. 1 (1): 6. doi:10.4102/jir.v1i1.18. ISSN 2960-0391.
  18. ^ Furmli, Suleiman; Elmasry, Rami; Ramos, Megan; Fung, Jason (October 9, 2018). "Therapeutic use of intermittent fasting for people with type 2 diabetes as an alternative to insulin". BMJ Case Reports. 2018: bcr2017221854, bcr–2017–221854. doi:10.1136/bcr-2017-221854. ISSN 1757-790X. PMC 6194375. PMID 30301822.