The People's Perspective on Medicine

Show 1143: Can You Control Your Blood Sugar by Fasting?

Intermittent fasting together with a diet low in refined carbohydrates can help many people with type 2 diabetes control their condition.
Jason Fung, MD, nephrologist and author of The Diabetes Code
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Can You Control Your Blood Sugar by Fasting?

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Type 2 diabetes has reached epidemic levels in the US and around the world. Although endocrinologists consider it a chronic, progressive disorder, some experts have seen that it is potentially reversible and may be preventable. What approaches are helpful? What role could fasting play?

Nephrologist Jason Fung, MD, says that you can’t manage a dietary disease without considering diet. There are two important considerations.

Dietary Considerations:

What Do You Eat?

First, how much sugar is in the diet? Fructose, which is part of sugar, can contribute to problems with insulin and blood sugar. A diet low in refined carbohydrates is less likely to contribute to trouble controlling insulin and blood sugar.

Should You Be Fasting?

Second, when do you eat? A schedule that restricts eating to no more than six or eight hours a day has been shown to help restore metabolic health. Fasting for two or three days a week can even reverse insulin resistance, as Dr. Fung and his colleagues documented in the case studies they published recently (BMJ Case Reports, Oct. 9, 2018). Three people with diabetes who had required insulin were able to reduce their HbA1c, their waist circumference and their weight. As a result of therapeutic fasting, they no longer need insulin to control their blood sugar.

This Week’s Guest:

Dr. Jason Fung is a Canadian nephrologist. He’s a world-leading expert on intermittent fasting and low-carbohydrate diet, especially for treating people with type 2 diabetes.  He has written three bestselling health books and co-founded the Intensive Dietary Management program.  Dr. Fung’s latest book is The Diabetes Code, Prevent and Reverse Type 2 Diabetes Naturally.   

His website is

Listen to the Podcast:

The podcast of this program will be available the Monday after the broadcast date. The show can be streamed online from this site and podcasts can be downloaded for free. CDs may be purchased at any time after broadcast for $9.99.

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    About the Author
    Joe Graedon is a pharmacologist who has dedicated his career to making drug information understandable to consumers. His best-selling book, The People’s Pharmacy, was published in 1976 and led to a syndicated newspaper column, syndicated public radio show and web site. In 2006, Long Island University awarded him an honorary doctorate as “one of the country's leading drug experts for the consumer.” .
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    Super-duper interview! Thank you Joe and Terry, and thank you, Dr. Fung! I’ll be watching some of your online talks and ordering at least one of your books. It’s refreshing to hear a doctor tell it like it is, without prejudice toward certain types of natural foods.

    I have read Dr Fung’ s books and started losing weight with intermittent fasting. I have metabolic resistance and am overweight but not diabetic yet. I have lost 12 lbs by fasting. It is so great, no counting calories, counting steps, food diary, etc. I can also afford better food as I am only eating every other day. I am now trying weekend fasts. The best thing is if I am hungry or have plans I eat. So glad Dr Fung is reaching a wider audience.

    Certainly Dr. Fung is right about limiting carbs and continuous snacking. However, one of the recommendations for people with GERD, acid reflux, is to have many small feedings over the course of the day, rather than 2 or 3 big meals They also say to end eating a few hours before bedtime, and so that part of the Doctor’s recommendation is in sync with the needs of people with reflux problems.

    Regarding GERD, mine went away after just a few days on the ketogenic diet (which is the low-carb diet that Dr. Fung and many others now recommend). When I went off the keto program temporarily, the GERD came back. For those who can’t fast due to GERD or meds that require some food in the stomach, simply adopting a keto diet can bring down blood sugar numbers — just not as quickly as with fasting.
    Thanks for covering this topic, People’s Pharmacy!

    Thanks! I ordered the book “The Diabetes Code.”

    I heard the podcast. I am familiar with Dr. Fung and his books and have heard him on you tube, etc. Your interview was a very good introduction to IF and pointed out all that it does respecting weight loss, insulin, type 2 diabetes and related items. But neither you nor Dr. Fung never mentioned that if one fasts for 16 hours, after about 12 hours you are in ketosis so you remain in ketosis for the remaining 6 hours of your fast.

    It would be a natural followup for you to interview an expert in ketosis and all the valuable health benefits when you go into ketosis such as seizure control, autoimmune disease benefits, mental clarity, alzheimer’s etc. Thank you, and I look forward to hearing that podcast.

    I re-listened to Dr. Flung this AM. I think I can fast for 20 hrs. But I’m wondering if you can drink coffee during the fast period or just water. I love your show, and it’s my wake up call every Saturday AM.
    Thank you!

    As I understand Dr Fung you can have black coffee, no added cream, milk or sugar.
    I prefer to drink water, or perhaps hot tea.

    You can have up to 6 cups of coffee on a fasting day, according to Dr. Fung’s excellent 2016 book The Complete Guide to Fasting: Heal Your Body Through Intermittent, Alternate-Day, and Extended Fasting. Black is best, but you can add 1-2 teaspoons of cream. Artificial sweeteners, on the other hand, are not allowed. He also says you can have one so-called Bulletproof Coffee on fast days.

    I had Type 2 diabetes for forty years and kept it pretty much “under control” (by the doctors’ too easygoing definition) ever since I learned about the low carb diet. But last year I learned about the Keto diet and intermittent fasting (which the Keto books recommend). Now, 40 years after my first diagnosis, my A1c test result is 5.3, low enough to be below the official diabetic, even pre-diabetic range. My “incurable” disease is in remission!

    I read many years ago that sugar [unrefined carbs] was a bigger cause of High BP than salt.
    Everyone laughed at me. Hooray for Dr. Fung! This possibility has been on my mind for decades, and I like being validated. Although I am unable to hear the podcast I have heard him speak elsewhere.

    I have had such extremely low blood pressure historically. About one year ago I had a TBI.
    That in itself is another story since the medical profession knows nothing–at least nothing to help so far. Dealing with so many side effects. Turns out true from the books I have been reading, so I am stuck and praying and waiting and hoping.

    However my question is: Ever since the concussion my BP has soared. Why? What can be done?
    My doctor prescribed Losartan, and now it has been recalled! I only took a low dose [1/2 =25 mg.] for about a week/10 days. Am trying to regulate it on my own. Last visit doctor BP was 126 or 129 which is still high for me. Previous visit was 168…172.

    Obviously jumps around erratically. Need more help beyond beets, please.
    Thank you

    Air date says November 17 but not the time. Additionally, all Los Angeles area stations listed only list programming is on Sundays only and none feature this speaker.

    Obesity was a lifelong struggle for me. I weighed over 200 lbs by third grade. Having tried everything and failed every time, I finally found a low carb (ketogenic) diet in June 2013. Since that time I’ve lost over 100 lbs and maintained that loss. I eat the best foods of my life and wear the smallest clothes. I’ve reversed several medical conditions. I love low carb so much that I can’t stop talking about it. Through social media (and 3 books), I’ve helped thousands, for free, change their lives. They, too, are amazed at how good they feel just eliminating processed foods and refined carbohydrates. Diabetes, PCOS, kidney disease, and obesity are frequently managed just by changing diet. If you’re considering a low carb diet, give it just 2 weeks and you will be amazed at the difference.

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