diabetes supplement
Diabetes Diet

Intermittent Fasting

People often fast for cosmetic, religious, or medical reasons. About 14 percent of American adults have reported that they have fasted to help control their weight. But I have begun to fast intermittently because it’s the natural way to eat — or not eat.

That fasting may appear at first glance to be unnatural just shows how far we have departed from our heritage. Eating three squares a day is certainly not what our paleolithic ancestors did. And if our paleolithic ancestors seem light years away from modern humans, just remember that the paleolithic period extended until the agricultural revolution, which was only about 300 generations ago. Genetically, we have hardly changed at all since them.

Articles by Dr. Michael Eades on his “Protein Power” blog first attracted my attention to intermittent fasting. The more I explored intermittent fasting, particularly in the work of Dr. Loren Cordain, like his book, The Paleo Diet, the more I knew that I had to check out that experience for myself.

In the past couple of weeks I made two intermittent fasts. The first was for 12 hours from sunrise to sunset and the second was 24 hours from dinner one night to dinner the next.

I drank only water, lemonade, and tea (both black and herbal). None with any calories. And plenty of it.

My 12-hour fast was similar to that of Muslims during the month of Ramadan. But hardly the same and not as challenging.

Since Muslims are the experts on fasting, I consulted with an imam, Ibrahim Kazerooni, before setting forth on my latest dietary experiment. He is both a friend and a member of my diabetes support group.

Ibrahim explained that Muslims can’t even drink water while fasting during the month of Ramadan. Their fasts last from 1 and 1/2 hours before sunrise until dusk. (As a Shiite Islamic priest, or imam, he was an Iraqi dissident who Saddam Hussein repeatedly imprisoned until Ibrahim was able to escape from Iraq in 1974; I understand that followers of Sunni Islam fast from dawn to sunset.)

“Take it easy at first,” Ibrahim explained. “Just do one day to start.”

He told me that the fast was beneficial for his blood glucose level, even it it was sometimes a bit too low. “It was no problem when I took my diabetes medication at night.”

People who have type 2 diabetes, as Ibrahim does, need to be careful of what they eat late at night when they break their fasts. They can lose weight, “if they don’t overload on sugar and starch.” He said that he lost seven pounds this time.

Now, after two fasts I am even more positive than I was from reading Drs. Eades and Cordain and from talking with Imam Kazerooni.

I did have brief headaches near the beginning of each fast. And a bit of a sore throat for a short while as I hiked during my first fast. At one point on the trail I felt hunger pains in my stomach for a few minutes. But I was amazed that otherwise I never got hungry.

My mood remained at a high level throughout. Physically, I may have even gained energy. For example, on my walk to the post office during the second fast I even did some intermittent jogging, something that I hadn’t done for several months.

I don’t take any diabetes drugs or other prescription medication. My blood glucose level once went down to 68 mg/dl, about as far as anyone with diabetes would want. The first thing on the morning after my second fast it was at 80 mg/dl, just below the 83 mark that Dr. Richard K. Bernstein, the leading exponent of a very low-carb diet, says that is the appropriate average for anyone. I lost 0.8 pounds, and now my weight is the lowest in eight months.

Later I thought to investigate the peer-reviewed articles on Medline and found this:

“Persons with Type 1 diabetes can participate safely in prolonged fasts [more than 25 hours] provided they reduce their usual insulin dose significantly and adhere to guidelines regarding glucose monitoring and indications for terminating fasting.”

People with type 1, unlike me, absolutely have to take insulin. And of course my intermittent fasts have not been “prolonged.”

I also found other studies indicating other benefits of intermittent fasting, including one that concludes:

“Reducing energy intake by controlled caloric restriction or intermittent fasting increases lifespan and protects various tissues against disease…”

Another study reported:

“It has previously been shown that fasting for the biblical period of 40 days and 40 nights is well within the overall physiological capabilities of a healthy adult.”

The experience freed me from the self-imposed tyranny of assuming that I just had to eat breakfast, lunch, and dinner. Skipping those meals even saved me lots of time in food preparation and eating.

In conclusion, the experience was so rewarding that I will continue intermittent fasts of various lengths. But not more than the biblical 40 days and 40 nights.

This article is based on an earlier version of my article published by HealthCentral.

Never Miss An Update

Subscribe to my free newsletter “Diabetes Update”

I send out my newsletter on first of every month. It covers new articles and columns that I have written and important developments in diabetes generally that you may have missed.

Previous Post Next Post

You Might Also Like These Articles

  • Sophie at

    Thanks for sharing what you’ve learned! I have been trying to find a answer to the following question and haven’t yet been able to. Perhaps you can, please? Is is safe to intermittently fast (eating for 8 hours and fasting for 16) daily while taking metformin? I’m on 500 mg a day and just started last week. My AIC is 5.7. (It was 6.0 two years ago and I drove it down to 5.6 with dietary changes and exercise). Thanks for your help!

    • David Mendosa at

      Good question, Sophie, and thanks for asking. Yes, intermittent fasting definitely is safe while you are taking metformin. However, when you are taking insulin injections or the oldest class of diabetes drugs (the sulfonylureas) it can be problematic, because they can make your blood glucose level go dangerously low when you aren’t watching carefully.

  • Richard at

    You might consider the “Eat Stop Eat” lifestyle. The original book, published in 2007, provides you all you need to know and the science, yes science, of how it works. David as you described some of the good and for me too a light headache. First the water and then the fat departs.

    Have you read the book? I would be interested in your comments.

    • David Mendosa at

      Dear Richard,

      Many thanks. But I have not been able to find the book in the Colorado library system or on Amazon. Who is the author and publisher?


  • Scott at

    yes, definately if you are in a healthy weight range eating less is better!

    all of my annoying afflications… headaches, carpal tunnel, bad sleep, constant hunger & thirst, went away in a few months of eating properly.

    Now I’ve hit the bottom of healthy weight range, and I need to actually eat more. Just trying to figure out best way to get the calories without problems popping up again.

  • Mary Ellen at

    Hi Scott

    I actually started eating only twice each day about 8 months before I was diagnosed. I was so hungry all the time, I used this method to try and curb my appetite and have some weight loss.

    As time has gone by, this has become an easy habit for me. And my meals are not big. I feel very uncomfortable eating a lot of food at one sitting. Eating too much also agravates my GERD. Eating lightly, less often, my GERD symptoms are gone.

    I wondered, if food raises blood sugar, if I eat less food and eat less often – isn’t that a good thing?

  • Scott at

    Interesting…Mary Ellen’s response makes me wonder more about a question I have…
    is it better to eat 5-6 small meals a day, or go hungry and have 2 big meals a day even if that means much bigger glucose spikes?

    In rural cultures that have very low diabetes rates people normally eat twice a day and just go hungry midday.

    As I was constantly snacking, anytime I was a bit hungry I would grab the cookies & chips, before being diagnosed with high range prediabetes. I wonder if a constant insulin load wears out the system more than big meals.

  • Mary Ellen at

    I am a type 2 and what has worked for me is eating only 2 meals each day – usually breakfast and dinner. I am on 100mg Metformin, 2x daily. I find I am rarely hungry. I don’t snack. When I do eat, I follow Dr. Bernstein’s plan. I have been doing this for about 1 1/2 years. Sometimes on the weekends, when I am home (as opposed to in an office), I may eat a bit more.

    Is anyone else doing something similar?

  • George at

    Jewish fasting is also from food AND water, we do it once per year at least on Yom Kippur for one day from sunset to sunset.
    To get a detox benefit from a fast (fasting from food, not water) you need to do at least 3 days, these days are hard for most people as you get unpleasant side-effects as the body cleanses itself. If you choose to fast beyond 3 days it gets much easier. Juice fasting is a very safe alternative. The longest I have ever juice fasted is 40 days (first 14 days was water-only fast). The bad thing is, I developed gall stones. The good news is I was able to get rid of them by natural non-surgical means using the olive oil/lemon juice/epsom salt method.
    George, Auckland, New Zealand

  • Staycee at

    Fasting is definitely more than just a way to lose weight. That is just a blessed side effect. Getting healthy is the ultimate goal. I agree you definitely need to take it easy, it can be just as hard on your system as it does good. You must do reasearch, and in many cases consult with your doctor. http://falconblanco.com/health/fasting.htm