Intermittent fasting — the best diet for type 2 diabetes?

Alarm clock with bells on the plate with fork and knife, lunch time concept, top view with copy space

Type 2 diabetes was once thought to be a chronic disease that could never be cured. You can start medications to control it, but those medications will be with you for life.

Now we know better. As Dr. Jason Fung has said, “People are focused on giving drugs to type 2 diabetes, but it is a dietary disease.”

He and his team at Intensive Dietary Management Program set out to prove that they can do better than drugs. They recently published a case report of three men with type 2 diabetes who were able to completely stop their insulin and most of the oral drugs while still improving their diabetes control.

BMJ: Therapeutic use of intermittent fasting for people with type 2 diabetes as an alternative to insulin

How did they do it? Intermittent fasting.

The subjects fasted for 24 hours three to four days per week, going from dinner to dinner without food, while eating lunch and dinner on the other days. They lost between 10 and 18% body weight and between 10 and 22% from their waist circumferences.

But here is the amazing part.

Starting from a daily average of 70 units of insulin, they safely stopped their insulin as quickly as five days into the protocol, with the longest taking only 18 days. That is a dramatic result!

Importantly, they were very closely monitored by the team at IDM. Fasting while taking diabetes medications can increase the risk of hypoglycemia, a potentially life-threatening lowering of blood glucose. Thus the warning that people should not try this without being monitored by an experienced healthcare provider.

When done correctly, however, intermittent fasting combined with a low carb diet may be the best treatment of type 2 diabetes that we have ever seen.

Thanks for reading,
Bret Scher, MD FACC

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29 comments

Top comments

  1. Peter
    I used intermittent fasting and a ketogenic diet to reverse my type 2 diabetes three years ago. My A1C is 5.5 from an 11.5 at diagnosis. Diet doctor and dr. Fung have been a life saver and true pioneers in helping people empower themselves from an outdated ineffective form of treatment.
    Read more →
  2. Rebecca
    What about the ADA diet 1000s of us T2 diabetics have been prescribed. Low calarie, low fat, most cal. from carbs... That got more meds more issues not well. 8 weeks on Intermittent Fasting and LCHF has 30 pounds gone and 4 meds gone out of my life. The crowd is educating themselves and taking action... Powerful.
    Read more →

All comments

  1. bill
    The title of the report, "Therapeutic use of intermittent fasting for people with type 2 diabetes as an alternative to insulin"
    is misleading. If you read the paper, the case for
    fasting being the effective component was confounded by the use
    of a low carbohydrate diet. They cannot conclude that fasting caused
    the changes they observed.
  2. valerie
    How can you say it is "the best" diet when no other diet was tested?
  3. Rebecca
    What about the ADA diet 1000s of us T2 diabetics have been prescribed. Low calarie, low fat, most cal. from carbs... That got more meds more issues not well. 8 weeks on Intermittent Fasting and LCHF has 30 pounds gone and 4 meds gone out of my life. The crowd is educating themselves and taking action... Powerful.
  4. Peter
    I used intermittent fasting and a ketogenic diet to reverse my type 2 diabetes three years ago. My A1C is 5.5 from an 11.5 at diagnosis. Diet doctor and dr. Fung have been a life saver and true pioneers in helping people empower themselves from an outdated ineffective form of treatment.
  5. Jared
    I'm interested in the language of "Reversed" vs. "well controlled."

    To me, reversed would mean that if you gave these subjects a glucose tolerance test, they'd have non-diabetic blood glucose levels at the end of the test. Is that what is happening?

    Either way, this is obviously amazing and should be screamed from the mountain tops.

    Reply: #25
  6. Mario
    I only follow the low carb diet ( 30 and 20 gr per day) for 6 months and the results are very good I stopped using Insulin glargine 18 units every day plus 10 mg Dapagliflozin plus metformin 850 mg x 3 per day. And despite the medications, my Hbc was always 7 or higher. Now my Hbc is 6 my glycemic levels in the morning are 95mg/dl and 2 hours postprandial the higher has been 110 the average is 97. I stop using all the medications 5 months ago. ca we call this Diabetes reversal ? Of course yes.
  7. Susannah Shoaf
    I am currently using intermittent fasting and a ketogenic diet to reverse my type 2 diabetes for the last 7 months. I was first diagnosed 1/2017. My A1C is 6.0 from an 12.1 at diagnosis. LCHF diet is saving my whole immediate family's life. Reading the Obesity Code and listening to Dr. Fung has been eye opening. Sugar is evil. I'm using 1/4th the metformin and monitoring my fasting blood sugar daily. I'm almost off metformin!! It works!!
  8. Debra Neese
    I am Hypoglycemic and have boughts of low blood sugar attacks frequently. Yet I am also Pre-diabetic (3) yr's ago and probably diabetic by now. Anyway, I've tried Keto and get quiet constipated. I want to do fasting but my doc says no because of low blood sugar. I also have hypothyroidism and Sjorgens disease.
    What's the best diet for me? I wish I didn't have to eat, its a pain. I want to fast simply because of its convenience. Can you help me please.
    Thank you Debra
    Reply: #10
  9. Darren
    After four months of being on the keto diet and doing one meal a day i have lost 40lbs. And my A1c went from 9.9 to 5.4 and my daily glucose levels range from 80-100. I know it works for me
  10. Michael
    I have found that constipation in KETO is often a result of your macros not being in sync. Make sure you keep your fat intake up. 75% fat, 20 % protein, 5% carb. My fitness pal app is a good macro calculator to use.
    Reply: #26
  11. Joanne josephsen
    Love fasting with Keto. Been Keto 4 years and fasting for 2 years.
  12. Mark
    I started this Keto journey in June 2018 and dropped weight as well as dropping my A1C levels. I went from 7.2 to 5.8 and my doc still has me on twice a day metformin and 1 statin. Originally he had me at 4 times a day metformin!
    I also told him about doing IF but he said that is not good for people with type 2, as that will increase your insulin levels. (I don't think he gets it and just makes money from the pill people). Anyway next doc appt. is in November so I am hoping to be at the so called 5.6 A1C that is considered not Diabetic. Anyone ever hear of your GP telling you Fasting is bad? Currently I do IF two days out of the week and feel fine.
  13. Belinda Preece
    Our GP is keto blind, fasting blind and although we sent him links to Dr's Eric Westman and Jason Fung, he has yet to check them out and educate himself.
  14. Maureen S
    My A1c has dropped from 9 to 6 doing low carb/keto. Another appt at the end of October will see if it has dropped further. Thinking it will. I do a 16/8 IF but find it impossible to do a 24 fast, let alone, 3 or 4 days a week. I just don't see why this would be the only way to recover. Or suggesting/telling people, this is the only way. I am having great success doing what I am doing.
  15. Susan
    Mark, I have found that fasting makes my levels increase. I measure my bg at around 7.30am having eaten nothing from around 8pm and it will be over 7. I check hourly from then on and it rises steadily to anything between 9 and 11. Once I have something to eat, it starts to fall. I guess it’s an extension of the ‘dawn phenomenon’. So your doctor isn’t completely wrong. I think it’s down to individuals as to whether fasting is suitable or not.
  16. Paul
    I’ve been low carb since November 2016 and my sugar levels were down to high normal by the end of December 2016. I stopped taking Metformin and my sugar levels remained normal. I also stopped taking Cholesterol lowering tablets. In May this year I stopped taking blood pressure tablets and my blood pressure remained at high normal and became more regular and consistent.

    The only thing that I am still struggling with, is my weight which although initially dropped as risen a little, mainly due to holidays 😎.

    I’ve might try this intermittently fasting to see if it reduces waistline.

  17. Heidi
    For those suffering from constipation, google ‘linseed ‘ or ‘flaxseed’ bread. This is low carb/keto and works like a charm - just remember to drink sufficient water to help it move along.
    Reply: #18
  18. Una
    It's an endless problem on this diet!I.

    Will have a look, thanks.

    For those suffering from constipation, google ‘linseed ‘ or ‘flaxseed’ bread. This is low carb/keto and works like a charm - just remember to drink sufficient water to help it move along.

  19. Maggie moore
    Keto is impressive and results based.
    Citing a study of THREE persons to make a case for it is NOT.
  20. Monica Hocking
    I was diagnosed with diabetes 7 months ago at 11.5. Six months on it is 5.5. All due to lchf and intermittent fasting.
  21. Penny
    Since going low carb i no longer have to take metformin and all my.blood results came back normal, weight is also starting to come.off,doctor is very pleased with my results, I am feeling so much better and healthier, still have a way to go but i know i can do it
  22. Susan Kundert
    One of the things that concerns me about the whole fasting concept is the confusion between "time-limited eating" (a.k.a., not snacking, not constantly eating), and multi-day fasts. I have had enormous success (A1c at 4.8, weight at goal and below, clothing size at 0 -2) just going keto with 2 meals a day, and NO SNACKING. This is probably 16/8, in fasting lingo. But on the official Fung FB page, there is mass confusion. People who really don't observe the fundamentals of ketogenic eating are obsessing about doing week-long fasts, and refeeding with garbage. My belief is that this is completely misguided. This is not rocket science. A basic ketogenic diet, with time-limited eating, will be more than enough to get most of us where we need to be. I am concerned that the emphasis on ever-longer periods of not eating has become a fetish for disordered behavior. It is normal to eat! It is not normal to repeatedly refrain from eating for a week or more at a time. Fasting as an end in itself threatens to become a substitute for living a productive life.
  23. Mary Ross
    I have been eating low carb, 50+ gm daily, for several years. When I began, constipation was a problem, along with leg cramps. My functional medicine doctor advised increasing my daily magnesium supplement and both problems ended.
  24. Vern
    I dropped my Insulin, and four other diabetes related medications 4 days after starting LCHF in February of 2017 and with the help of the occasional fast up to five days have maintained an HbA1c of less than 6.3 and hope to been under 6 next blood test. I was never under 7 with the insulin and meds and getting worse over 23 years. I am now promoting this life changing ancient diet to everyone who will listen.
  25. Peter
    “I'm interested in the language of "Reversed" vs. "well controlled." To me, reversed would mean that if you gave these subjects a glucose tolerance test, they'd have non-diabetic blood glucose levels at the end of the test. Is that what is happening?”

    What you are referring to would mean cured. Reverse implies that the glucose levels have reverted back to within “normal” levels. Regardless, reversing diabetes stills allow someone with type 2 to reap all the benefits of being ‘cured’ similar to a cancer patient who has gone into remission. Yes, I am shouting from the mountain tops, because unlike my grandmother and all who have suffered needlessly not knowing that there was another way! I feel privileged and fortunate to live in the times that we do. Education is power!

  26. Una

    I have found that constipation in KETO is often a result of your macros not being in sync. Make sure you keep your fat intake up. 75% fat, 20 % protein, 5% carb. My fitness pal app is a good macro calculator to use.

    What are macros? I though we only had to cunt carbs?

  27. Rondal
    I started keto in June with 16:8 IF,A1C went from 9.2 to 7.0 and lost 30 pounds. Doctor is extremely happy. Stopped taking all sugar medicine when I started keto. It took 4 months to get my blood sugar levels to normal levels on a daily basis. I also have the dawn effect but it is starting to go away.
  28. Bob Harris
    I'm done asking for permission after 15 years of doing it their way only to be told that the oral medications not working and I'm going to have to start on insulin I'm insulin resistant it is idiotic to think that giving me insulin in my insulin resistant state is going to improve me or help me in anyway I've started to take matters into my own hands safely testing slowly it's working for me if he can't abide by my choices then I'll fire him and get another doctor
    Reply: #29
  29. Gentiann
    Good for you, Bob!
    Sometimes, it's better to have a "don't ask, don't tell" attitude. However, don't fire your doctor yet: surprise him in 6 months with your next blood test and weight loss. This may not make him a convert but, at least, bring him to raise some questions.

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