How permanent is the effect of intermittent fasting on insulin resistance?

July 16 2016 by in Dr. Jason Fung, Intermittent fasting, Q&A

There are tons of questions about intermittent fasting, like these:

How permanent is the effect of intermittent fasting on insulin resistance?
Does whey protein supplements help lower blood sugars?

Dr. Jason Fung is one of the world’s leading experts on fasting for weight loss or diabetes reversal. Here are a his answers to those questions and more:

Fasting and insulin resistance

Dr Fung,
I have a few questions:

1. How permanent is the IF on the insulin resistance? After you lower the insulin resistance through a regimen of fasting, is it sustainable or you have to do it for life. As you mentioned, most weight loss diet are not reversible. So I wonder whether IF is sustainable.

2. In this study, it is mentioned that whey protein helps to lower blood sugar. For me, I take Whey after a gym regimen to help to build muscles. I am TD2. Is it harmful to take whey (not excessive – just about one spoonful provided by the Whey protein can).

3. What about Monk Fruit (natural – not processed). Is it OK to drink that or mix it with your drink?
Seng

Dr. Jason Fung:

1. It is not permanent. It’s like taking a bath. You can’t do it once and expect to be clean forevere.
2. I don’t recommend it. Stick to real food.
3. No.

Aspirin

Dr. Fung, thanks for the reply to previous questions, now have one about baby aspirin. I’ve been taking a daily baby aspirin in addition to all the oils for blood lubricity, and with all the bad press I’ve been reading lately I’m beginning to question the wisdom of that. I’m thinking the oils I’m taking : fish oils, avocado oils, olive oils, Vit E in tocotrienol form, and Vit. D’s, are enough to keep blood lubed up plenty good. Question is do I really need the baby aspirin. I know from your book “The Obesity Code” that you don’t seem to hot on the idea of aspirin. Whats the verdict?
1. Does aspirin artifically stimulate insulin?
2. Is aspirin a good thing to be taking regularly to help prevent heart attacks?
3. Other then use for a say, monthly headache is aspirin something a person wants in their diet?

Thanx in advance Doc !
Jimmy

Dr. Jason Fung:

1. No
2. No. Only in secondary prevention. The recommendation that everybody of the age of 60 take an aspirin a day is old and has since been retracted. It is a drug and has use in specific patient groups, not everybody willy-nilly.
3. No.

Intolerance to dairy and fasting tricks

Hi Dr Fung – thank you for your reply to my previous questions.
I’m now on Day 3 of my fast and feel good.
I introduced double cream (15mls) to each of my 3 coffees today, and it is becoming clear that I am intolerant to dairy products as my skin has already deteriorated after improving over the first 2 days of the fast. So:
1) Could I substitute canned coconut milk for the double cream? (15mls / serving x 3)
Also
2) Are micronutrients stored within fat cells in the body. If not, how do you maintain electrolyte balance whilst fasting?
3) Would taking 2 tbsps raw organic apple cider vinegar daily be a good idea whilst fasting?
4) You suggested alternate day fasting at the end of a fast. – would this be a water fast or 500 calories as suggested by Dr Krista Varady in The Every Other Day Diet?

Margaret

Jo

Dr. Jason Fung:

1. Yes. Try coconut cream instead of coconut milk. It’s delicious.
2. A general multi-vitamin supplement for extended fasts.
3. Yes
4. Either works.

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16 comments

1 comment removed
2
Natalie
July 25 2016
Hi,
I am new to your website but have been doing LCHF for about 18months. I am keen to try Intermittent fasting, I did 2 days last week and found I had no problem and liked the results.(I did no exercise on those days). I do quite a bit of running and have just completed a marathon. My runs at the moment are not long as I am still recovering.
I normally run early in the mornings in a fasted state. My question is, is it ok to do Intermittent fasting while exercising or should I be consuming a meal of good carbs, fats and protein post exercise even if it's of short duration (30 minutes).

Thank you
3
Zepp
July 25 2016
Do as you feel good of!

30 minutes is what everbody should do.. att least!
4
Earle Wignall
August 26 2016
The above analysis leads to several prospects for the intermittent faults dependability enhancement strategy. Comprehensive fault injections have been conducted to characterize the effects of transient faults on processors. As semiconductor technology scales into the nanometer regime, a resurgence of interest in intermittent faults has c 858 ome forth in recent years.
5
Trevor
November 10 2016
I've seen it mentioned that cream in coffee during a fast is acceptable. What about other fats like butter and/or coconut oil? Also, would buttered broth be acceptable?

Reply: #6
6
Reply to comment #5 by Trevor
Peter Biörck Team Diet Doctor
November 15 2016
Hi Trevor!

If you use small amounts of "pure" fat it's even better than cream. :)

I've seen it mentioned that cream in coffee during a fast is acceptable. What about other fats like butter and/or coconut oil? Also, would buttered broth be acceptable?
7
Amy
March 29 2018
I've been told to take an aspirin a day for cancer risk. Can I continue to do this while fasting? Or should I stop while fasting and resume afterwards? (My main reason for fasting is also to reduce cancer risk due to familial genetic risk)
8
Juddee’
January 7 2019
Dr. Fung:
Your book is excellent. I have been fasting every other day for 36 hours or more. On the fasting days I have not been doing any insulin. My blood sugar climbs back up to around 122 on fasting days. On food days I take insulin, 15 ml twice daily. Should I be taking any insulin on my fasting days? Thank you.

Reply: #9
9
Reply to comment #8 by Juddee’
Kristin Parker Team Diet Doctor
January 7 2019
Please work with your doctor regarding any questions about medication dosage.
10
Steven Svoboda
January 19 2019
Hello, I have a question about if fasting causes temporary insulin resistance? Dr. Peter Attia talked about how after a long fast, he took an oral glucose tolerance test and found he had significant postprandial glucose elevation but wasn't quite sure why this would be... Would this transient insulin resistance possibly be because you have cortisol around when fasting which is needed to stimulate gluconeogenesis in order to maintain basal blood glucose levels. Then, when you refeed with a carby meal, it appears as if you are insulin resistant bc it takes a little while for cortisol to decrease and for your cells to switch back to utilizing glucose. However, its only transient because fasting increases AMPK which increases GLUT4 receptors ultimately increasing insulin sensitivity in the long run. Thus the transient insulin resistance that occurs from cortisol during fasting really wouldn't matter if you aren't consuming any carbs. The glucose being produced in your liver is only really supplying cells that require it such as RBCs and brain cells to a small degree. Thus this insulin resistance that occurs may be a mechanism to ensure that glucose is preferentially utilized by cells that require it? Does this make sense mechanistically?

Thank you,
highly curious medical student
11
Renn Van Niekerk
September 1 2019
Hi I have Lupus SLE and take many meds. Is it ok for me to take meds on the 16/8 intermittent fasting? Thanks

Reply: #12
12
Reply to comment #11 by Renn Van Niekerk
Kristin Parker Team Diet Doctor
September 3 2019

Hi I have Lupus SLE and take many meds. Is it ok for me to take meds on the 16/8 intermittent fasting? Thanks

Please check with your doctor regarding the safety of fasting with Lupus and timing of your medications.
13
Mark W.
November 22 2019
Just dropped in to say 'thank you' for your work.

I've lost nearly 10% of my body weight in the last six weeks, and I've never felt more in control of my body weight and food intake in my life. Your books have been life-changing for me, and there are no words to adequately communicate my gratitude.

I've been telling EVERYONE about your books. The unofficial sub-title I've given both The Obesity Code and The Complete Guide to Fasting is 'an owner's manual for your mouth'. Yours to use in publication without attribution, should you so wish.

Thank you, so much, Dr. Fung.
14
Boo
September 18 2020
I'm pretty sure I'm insulin resistant. I have yo-yo dieted all of my life and since the 90s I always lost weight through the original Atkins way. Unfortunately, I didn't realize how damaging carbs were so I would just go off Atkins and assume that I'd eventually get back on. Fast forward to today. I'm 53. I started on keto in Feb of 2018 because I went to the doctor and weighed at 267 and she wanted to put me on all of these ridiculous meds. The only one I took was the albuterol because I have had asthma since I was born. I refuse to take the steroid inhaler. She does not like that I am keto. She doesn't like fasting. She thinks I should be eating no more than 1200 calories per day. So I ignored her pleas and went on keto, lost 45 pounds or so in 9 months then stalled for over a year. No matter what I did I would lose some then stall and gain it back. I started IF with no change. Did carnivore, lost 9 pounds then stalled for 7 more months. Since August I've been doing a mix of IF, alternate day fasting and extended fasting (I'm at 46 hours at the moment.) I've lost 6 pounds doing this since August. Which is funny because in the 90s I'd lose 90 pounds in 3 months on Atkins. Anyway, my doctor is pretty much uncooperative in any of this. She gets mad at me, flashes her education in my face when I tell her what works for me, etc. It was like pulling teeth to get a c-peptide test out of her even though my fasting glucose as been 110 and 130 and I did have high blood pressure issues when there (for good reason, she raises it!) So, long story short, I'm at 215 now. My morning blood sugar is between 97 to 120 and late in the afternoon it is in the mid 90s and this is even the first 2 days of fasting, which I understand the liver is getting rid of the stored sugar. It takes about 3 days for mine to get in the 80s. Will this always be the case? Or, will it reset at some point while I'm fasting? Because at that rate the only way I'll lose is with extended fasts and right now I could really go for a nice ribeye with butter. I don't eat carbs at all unless it comes from my coffee beans, eggs, or a side of broccoli or salad and that is only a couple of times per month. How do I measure IR and get rid of it for good? Is it even possible so I don't jump up to a 100 when eating just steak and butter? or is that normal? I know, so many questions. Thanks :)

Reply: #15
15
Reply to comment #14 by Boo
Crystal Pullen Team Diet Doctor
September 18 2020

I'm pretty sure I'm insulin resistant. I have yo-yo dieted all of my life and since the 90s I always lost weight through the original Atkins way. Unfortunately, I didn't realize how damaging carbs were so I would just go off Atkins and assume that I'd eventually get back on. Fast forward to today. I'm 53. I started on keto in Feb of 2018 because I went to the doctor and weighed at 267 and she wanted to put me on all of these ridiculous meds. The only one I took was the albuterol because I have had asthma since I was born. I refuse to take the steroid inhaler. She does not like that I am keto. She doesn't like fasting. She thinks I should be eating no more than 1200 calories per day. So I ignored her pleas and went on keto, lost 45 pounds or so in 9 months then stalled for over a year. No matter what I did I would lose some then stall and gain it back. I started IF with no change. Did carnivore, lost 9 pounds then stalled for 7 more months. Since August I've been doing a mix of IF, alternate day fasting and extended fasting (I'm at 46 hours at the moment.) I've lost 6 pounds doing this since August. Which is funny because in the 90s I'd lose 90 pounds in 3 months on Atkins. Anyway, my doctor is pretty much uncooperative in any of this. She gets mad at me, flashes her education in my face when I tell her what works for me, etc. It was like pulling teeth to get a c-peptide test out of her even though my fasting glucose as been 110 and 130 and I did have high blood pressure issues when there (for good reason, she raises it!) So, long story short, I'm at 215 now. My morning blood sugar is between 97 to 120 and late in the afternoon it is in the mid 90s and this is even the first 2 days of fasting, which I understand the liver is getting rid of the stored sugar. It takes about 3 days for mine to get in the 80s. Will this always be the case? Or, will it reset at some point while I'm fasting? Because at that rate the only way I'll lose is with extended fasts and right now I could really go for a nice ribeye with butter. I don't eat carbs at all unless it comes from my coffee beans, eggs, or a side of broccoli or salad and that is only a couple of times per month. How do I measure IR and get rid of it for good? Is it even possible so I don't jump up to a 100 when eating just steak and butter? or is that normal? I know, so many questions. Thanks :)

Let's take a step back for a moment and check out this article on diabetes with fresh eyes. https://www.dietdoctor.com/diabetes The evidence basing within this article confirms that a low carb/keto diet is an excellent tool in the fight against Type 2 diabetes and insulin resistance. Then, consider starting our 10 Week Weight Loss for Good Course. Sometimes, after a long while on a journey by ourselves, we get off the path without even realizing it. This may be the perfect opportunity for you to get back on track and see results in both your blood glucose and your weight. https://www.dietdoctor.com/how-to-lose-weight/10-weeks
16
Mark
August 28 2022
Hi Dr. Fung,

I had been prediabetic for 15 years, with fasting glucose levels at between 105 and 115. I had the tingly hands and feet and a bit of belly fat but more edema, in part due to writing books. I went onto a IF regimen and whacked the lectins per Dr. Gundry's recommendations. I lost thirty pounds in just a few months, now at 6'-0" and 165#.
I get a fasting glucose number monthly along with hemoglobin and ferritin (donate blood regularly). Now, after 30 months of IF (I'm 68), the glucose went down all right, but only to 95-98, even after a fast of 18 hours.

The complication is that I do heavy and occasionally dangerous high-skill labor (such as tree climbing with a chainsaw) along with writing, research, and high acuity manual work, so I can't afford to be light headed or I could wind up with a rather severe health problem of another sort! The time of dinner is regulated by when my wife gets home from work, which can mean that we don't finish up eating unitl 10:00PM (I work late in the summer time anyway). So for me to do intermittent fasting, it has to be through the morning until past lunch hour. Coffee helps in the morning, but the results are iffy until noon to one, when I'm feeling a bit better.

So now after 2-1/2 years of this routine, I'm wondering if I have to do something more extreme to get the fasting glucose back down to the high 80s to low 90s where it belongs OR how much longer should I expect it to take to get there with 14-17 hours of daily IF? Are my goals unrealistic or is there some other approach I should be taking?

Thanks!

Reply: #17
17
Reply to comment #16 by Mark
Kerry Merritt Team Diet Doctor
August 29 2022

Hi Dr. Fung,
I had been prediabetic for 15 years, with fasting glucose levels at between 105 and 115. I had the tingly hands and feet and a bit of belly fat but more edema, in part due to writing books. I went onto a IF regimen and whacked the lectins per Dr. Gundry's recommendations. I lost thirty pounds in just a few months, now at 6'-0" and 165#.
I get a fasting glucose number monthly along with hemoglobin and ferritin (donate blood regularly). Now, after 30 months of IF (I'm 68), the glucose went down all right, but only to 95-98, even after a fast of 18 hours.
The complication is that I do heavy and occasionally dangerous high-skill labor (such as tree climbing with a chainsaw) along with writing, research, and high acuity manual work, so I can't afford to be light headed or I could wind up with a rather severe health problem of another sort! The time of dinner is regulated by when my wife gets home from work, which can mean that we don't finish up eating unitl 10:00PM (I work late in the summer time anyway). So for me to do intermittent fasting, it has to be through the morning until past lunch hour. Coffee helps in the morning, but the results are iffy until noon to one, when I'm feeling a bit better.
So now after 2-1/2 years of this routine, I'm wondering if I have to do something more extreme to get the fasting glucose back down to the high 80s to low 90s where it belongs OR how much longer should I expect it to take to get there with 14-17 hours of daily IF? Are my goals unrealistic or is there some other approach I should be taking?
Thanks!

Hi, Mark! We are unable to give medical advice, and we would recommend discussing this with your physician. If you'd like to try contacting Dr. Fung directly, you can try his website. https://www.thefastingmethod.com/

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