Jason Fung

Last updated
Jason Fung
Born1973
Occupation(s)Nephrologist, writer

Jason Fung (born in 1973) is a Canadian nephrologist and functional medicine advocate who promotes a low-carbohydrate high-fat diet; and intermittent and extended fasting. [1] [2] [3] [4] Fung disputes the current saturated fat guidelines.

Contents

Biography

Fung graduated with his medical degree from the University of Toronto, [5] and completed his residency and fellowship in nephrology at the University of California, Los Angeles. [6] [3] He is the director of the nonprofit organization Public Health Collaboration. [1]

Fung is an author of many low-carbohydrate diet books. [7] His first book, The Complete Guide to Fasting, [8] co-authored by Jimmy Moore was published in fall 2016 [9] and offered insight to all aspects of fasting culture. [10]

The Obesity Code and The Diabetes Code were subsequently published in 2016 and 2018. [11] [12] His book The Obesity Code Cookbook was published in 2019. [13] In 2021, Fung co-authored The Diabetes Code Cookbook with Alison Maclean. [7] In 2020, Fung co-authored with naturopath Nadia Brito Pateguana The PCOS Plan: Prevent and Reverse Polycystic Ovary Syndrome Through Diet and Fasting. [14] [15] His book The Cancer Code, published in 2020 advocates intermittent fasting and a low-carbohydrate diet to reduce cancer risk. [16]

Reception

Fung's book The Obesity Code received a 31% score for scientific accuracy and an overall score of 60% by Red Pen Reviews. [17] The 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". [17]

Selected publications

Related Research Articles

Dieting is the practice of eating food in a regulated way to decrease, maintain, or increase body weight, or to prevent and treat diseases such as diabetes and obesity. As weight loss depends on calorie intake, different kinds of calorie-reduced diets, such as those emphasising particular macronutrients, have been shown to be no more effective than one another. As weight regain is common, diet success is best predicted by long-term adherence. Regardless, the outcome of a diet can vary widely depending on the individual.

<span class="mw-page-title-main">Polycystic ovary syndrome</span> Set of symptoms caused by abnormal hormones in females

Polycystic ovary syndrome, or polycystic ovarian syndrome (PCOS), is the most common endocrine disorder in women of reproductive age. The syndrome is named after cysts which form on the ovaries of some women with this condition, though this is not a universal symptom, and not the underlying cause of the disorder.

<span class="mw-page-title-main">Metabolic syndrome</span> Medical condition

Metabolic syndrome is a clustering of at least three of the following five medical conditions: abdominal obesity, high blood pressure, high blood sugar, high serum triglycerides, and low serum high-density lipoprotein (HDL).

Insulin resistance (IR) is a pathological condition in which cells in insulin-sensitive tissues in the body fail to respond normally to the hormone insulin or downregulate insulin receptors in response to hyperinsulinemia.

<span class="mw-page-title-main">Metformin</span> Medication used to treat diabetes

Metformin, sold under the brand name Glucophage, among others, is the main first-line medication for the treatment of Type 2 diabetes, particularly in people who are overweight. It is also used in the treatment of polycystic ovary syndrome, and is sometimes used as an off-label adjunct to lessen the risk of metabolic syndrome in people who take antipsychotics. It has also been shown to inhibit inflammation, and is not associated with weight gain. Metformin is taken orally.

<span class="mw-page-title-main">Low-carbohydrate diet</span> Diets restricting carbohydrate consumption

Low-carbohydrate diets restrict carbohydrate consumption relative to the average diet. Foods high in carbohydrates are limited, and replaced with foods containing a higher percentage of fat and protein, as well as low carbohydrate foods.

Anovulation is when the ovaries do not release an oocyte during a menstrual cycle. Therefore, ovulation does not take place. However, a woman who does not ovulate at each menstrual cycle is not necessarily going through menopause. Chronic anovulation is a common cause of infertility.

<span class="mw-page-title-main">Hyperandrogenism</span> Excess androgens (male-related hormones) in the body

Hyperandrogenism is a medical condition characterized by high levels of androgens. It is more common in women than men. Symptoms of hyperandrogenism may include acne, seborrhea, hair loss on the scalp, increased body or facial hair, and infrequent or absent menstruation. Complications may include high blood cholesterol and diabetes. It occurs in approximately 5% of women of reproductive age.

<span class="mw-page-title-main">High-protein diet</span> A diet high in protein

A high-protein diet is a diet in which 20% or more of the total daily calories come from protein. Many high protein diets are high in saturated fat and restrict intake of carbohydrates.

<span class="mw-page-title-main">Hyperinsulinemia</span> Abnormal increase in insulin in the bloodstream relative to glucose

Hyperinsulinemia is a condition in which there are excess levels of insulin circulating in the blood relative to the level of glucose. While it is often mistaken for diabetes or hyperglycaemia, hyperinsulinemia can result from a variety of metabolic diseases and conditions, as well as non-nutritive sugars in the diet. While hyperinsulinemia is often seen in people with early stage type 2 diabetes mellitus, it is not the cause of the condition and is only one symptom of the disease. Type 1 diabetes only occurs when pancreatic beta-cell function is impaired. Hyperinsulinemia can be seen in a variety of conditions including diabetes mellitus type 2, in neonates and in drug-induced hyperinsulinemia. It can also occur in congenital hyperinsulinism, including nesidioblastosis.

<i>The China Study</i> 2005 book by T. Colin Campbell and Thomas M. Campbell II

The China Study: The Most Comprehensive Study of Nutrition Ever Conducted and the Startling Implications for Diet, Weight Loss and Long-term Health is a book by T. Colin Campbell and his son, Thomas M. Campbell II. The book argues for health benefits of a whole food plant-based diet. It was first published in the United States in January 2005 and had sold over one million copies as of October 2013, making it one of America's best-selling books about nutrition.

<span class="mw-page-title-main">Follicular atresia</span>

Follicular atresia refers to the process in which a follicle fails to develop, thus preventing it from ovulating and releasing an egg. It is a normal, naturally occurring progression that occurs as mammalian ovaries age. Approximately 1% of mammalian follicles in ovaries undergo ovulation and the remaining 99% of follicles go through follicular atresia as they cycle through the growth phases. In summary, follicular atresia is a process that leads to the follicular loss and loss of oocytes, and any disturbance or loss of functionality of this process can lead to many other conditions.

Ovarian diseases refer to diseases or disorders of the ovary.

Intermittent fasting is any of various meal timing schedules that cycle between voluntary fasting and non-fasting over a given period. Methods of intermittent fasting include alternate-day fasting, periodic fasting, such as the 5:2 diet, and daily time-restricted eating.

Hyperthecosis, or ovarian hyperthecosis, is hyperplasia of the theca interna of the ovary. Hyperthecosis occurs when an area of luteinization occurs along with stromal hyperplasia. The luteinized cells produce androgens, which may lead to hirsutism and virilization in affected women.

<span class="mw-page-title-main">Weight management</span> Techniques for maintaining body weight

Weight management refers to behaviors, techniques, and physiological processes that contribute to a person's ability to attain and maintain a healthy weight. Most weight management techniques encompass long-term lifestyle strategies that promote healthy eating and daily physical activity. Moreover, weight management involves developing meaningful ways to track weight over time and to identify the ideal body weights for different individuals.

Infertility in polycystic ovary disease (PCOS) is a hormonal imbalance in women that is thought to be one of the leading causes of female infertility. Polycystic ovary syndrome causes more than 75% of cases of anovulatory infertility.

<span class="mw-page-title-main">Cortisone reductase deficiency</span> Medical condition

Cortisone reductase deficiency is caused by dysregulation of the 11β-hydroxysteroid dehydrogenase type 1 enzyme (11β-HSD1), otherwise known as cortisone reductase, a bi-directional enzyme, which catalyzes the interconversion of cortisone to cortisol in the presence of NADH as a co-factor. If levels of NADH are low, the enzyme catalyses the reverse reaction, from cortisol to cortisone, using NAD+ as a co-factor.
Cortisol is a glucocorticoid that plays a variety of roles in many different biochemical pathways, including, but not limited to: gluconeogenesis, suppressing immune system responses and carbohydrate metabolism.
One of the symptoms of cortisone reductase deficiency is hyperandrogenism, resulting from activation of the Hypothalamic–pituitary–adrenal axis. The deficiency has been known to exhibit symptoms of other disorders such as Polycystic Ovary Syndrome in women. Cortisone Reductase Deficiency alone has been reported in fewer than ten cases in total, all but one case were women. Elevated activity of 11β-HSD1 can lead to obesity or Type II Diabetes, because of the role of cortisol in carbohydrate metabolism and gluconeogenesis.

Obesity is defined as an abnormal accumulation of body fat, usually 20% or more over an individual's ideal body weight. This is often described as a body mass index (BMI) over 30. However, BMI does not account for whether the excess weight is fat or muscle, and is not a measure of body composition. For most people, however, BMI is an indication used worldwide to estimate nutritional status. Obesity is usually the result of consuming more calories than the body needs and not expending that energy by doing exercise. There are genetic causes and hormonal disorders that cause people to gain significant amounts of weight but this is rare. People in the obese category are much more likely to suffer from fertility problems than people of normal healthy weight.

<span class="mw-page-title-main">HAIR-AN syndrome</span> Medical condition

The HAIR-AN syndrome is a rare subtype of polycystic ovary syndrome (PCOS) characterized by hyperandrogenism (HA), insulin resistance (IR) and acanthosis nigricans (AN). The symptoms of the HAIR-AN syndrome are largely due to severe insulin resistance, which can be secondary to blocking antibodies against the insulin receptor or genetically absent/reduced insulin receptor number/function. Insulin resistance leads to hyperinsulinemia which, in turn, leads to an excess production of androgen hormones by the ovaries. High levels of androgen hormones (hyperandrogenism) in females causes excessive hair growth, acne and irregular menstruation. Patients with both underlying mechanisms of insulin resistance may have more severe hyperandrogenism. Insulin resistance is also associated with diabetes, heart disease and excessive darkening of the skin

References

  1. 1 2 "Jason Fung, MD". The Institute for Functional Medicine.
  2. ↑ Bowyer, Jerry. "Is Fasting The Cure For Bloated Healthcare Costs?". Forbes.
  3. 1 2 "Dr. Jason Fung, MD". Diet Doctor.
  4. ↑ "People Are Voluntarily Going Months Without Food". The Atlantic . 21 November 2016.
  5. ↑ "Why outdated information is to blame for weight gain". Fox News. September 23, 2016.
  6. ↑ "About". Dr. Jason Fung.
  7. 1 2 "Books". Dr. Jason Fung.
  8. ↑ Khazan, Olga (November 21, 2016). "People Are Voluntarily Going Months Without Food". The Atlantic.
  9. ↑ "Complete Guide To Fasting: Heal Your Body Through Intermittent, Alternate-day, And Extended Fasting". indigo.ca.
  10. ↑ "Jason Fung". www.swissre.com.
  11. ↑ "The Obesity Code: Unlocking the Secrets of Weight Loss". redpenreviews.org. Retrieved 24 October 2022.
  12. ↑ Scherger, Joseph E. (2019). "The Diabetes Code". Fam Med. 51 (3): 286–287. doi: 10.22454/FamMed.2019.998853 . S2CID   76663782.
  13. ↑ "International: 30 bestselling books for the week of Dec. 21". vancouversun.
  14. ↑ "Doctor Nadia - PCOS". doctornadia.
  15. ↑ "The PCOS Plan: Prevent and Reverse Polycystic Ovary Syndrome through Diet and Fasting". indigo.ca.
  16. ↑ Fung, Dr Jason (November 10, 2020). The Cancer Code by Dr. Jason Fung. HarperCollins Publishers. ISBN   9780062894007 – via www.harperwave.com.
  17. 1 2 Yoder, Seth (2019). "The Obesity Code: Unlocking the Secrets of Weight Loss". Red Pen Reviews. Archived from the original on October 24, 2022.
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