Physiological Insulin Resistance

I’ve been meaning to do a deep dive into physiological insulin resistance for quite a while now, but the universe keeps conspiring to take my time.  Because I haven’t had time to read, learn more and write about it, I thought I’d share the links I have accumulated thus far. Mostly because I’ve now been asked a variant of the following multiple times, or have seen the following posted on various forums for discussing nutrition, health, and low carbohydrate diets:

“Why has my blood glucose gone up on a low carb diet?”

Typically this is accompanied by a good deal of anxiety and fretting over glucometers.

I should know, I watched my blood glucose increase by a few points as I’ve sustained my low carb diet. My understanding is that this is a known adaptation completely unrelated to the insulin resistance concomitant with diabetes.

While I’m not the person you should ask about anything health related, I’ve wanted an answer to this question myself. The explanation I’ve read is that after going low carb, your muscle tissue becomes insulin resistant in order to preserve serum glucose availability for the brain. If your muscle tissue did not do this, reduced availability of glucose in the serum could (theoretically) put your in dire straights if your brain can’t meet minimal demand for glucose. (Mind you, even on a zero carb diet you can meet all your glucose requirements via gluconeogenesis. The point is, your body needs a way to tell your muscle mass to stop taking all the glucose it makes. This is that way.)

Because of this physiological insulin resistance,which I should mention is a benign state that is not making your diabetic insulin resistance worse, you wouldn’t want to take an oral glucose tolerance test while you are low carbing.

If you took a glucose tolerance test while on a low carb or ketogenic diet, you would fail. If you need to take such a test (and you want it to be accurate), increase your carbohydrate intake to ~150g for a few days and then take the oral glucose tolerance test.  The few days of increased carbohydrate intake will apparently let your body adapt to increased carbohydrate availability and your physiological insulin resistance will go away.

At any rate, that’s my extremely flawed, 2 minute brain dump on it based on a very limited bit of reading on the subject. For the record, I discussed my increased blood sugar with my doctor. I asked him if the explanation I gave above is the reason, and he indicated it was…but we didn’t spend a lot of time on this point.

If you are interested, here are some links that I started collecting on the subject of physiological insulin resistance. Not all are good sources, some are likely blind alleys, but they were part of my research notes, so I’ll share them in the Resources section below in the hopes that they will be of use to someone.


12 Responses to “Physiological Insulin Resistance”

  1. Hi Michael,

    I haven’t gone through all your links at this time, lack of time. I find the explanations for PIR strange and have a question that may straighten out this at least for me.

    First I think that eating 150 g carbs per day for a few days would clearly “restart a dormant carb/insulin cycle”, and does not need to have anything with insulin resistance to do. Insulin resistance cannot be reveresed in a few days what I know.

    The other thing is that from what I have read it appears that blood sugar goes way over 5.5 as weight loss stalls, a high blood sugar which would be a reason to worry. But the explanation “preserve blood sugar” seems then totally flawed to as I work very well with at BS 80 (or below 4). Why should the set point suddenly shift up when BS 4 was sufficient for muscles and other only glucose dependent tissues before?

    If it is like that I would buy it, but only if it happens to (young) people that have never been insulin resistant ! Not owerweight, fasting insulin at 3-5 and good fasting blood sugar taking up a low carb diet with the PIR developing. Are there any such examples ?

    What I mean is that for older people with some overweight – those ones who go on a low carb diet for good reasons – the chain of events is different:

    First there is insulin resistance present, as it is hard to gain unwanted weight without it.

    Subsequent weight loss through LCHF reduces this somewhat and during the same time the low blood sugars starts up glucogenesis, something that have been dormant often for decades while feeding on the SAD. I call this period the “honey moon period” when it comes to weight loss and blood sugar. It may take 6 months on a low carb diet before the liver has adapted to produce the glucose not coming from the food any more, seemingly starting tp make ketones much sooner as we know.

    Nut once the honey moon is over, weight loss ceases and morning sugar starts increasing. This is what some calls PIR, which I am not quite sure it is. Only reason I can see that sugar (again!) starts to be regulated over 5.5 is that the pancreas glucagon production was out of wack before the low carb diet and is then STILL(!) out of tune. The very reason we became fat in the first place. One answer may be to get the pancreas MRI-scanned to measure the fat inside it and around it. Visceral fat (VF).

    Or just start an intermittent fasting period to get that last (skinny fat) visceral fat to go away. If people that are truly skinny can have such bad fat it does not seem strange that it is the last to remain also for people that were fat before. If it fails get the MRI scan and find out !

    The crucial fact is that a UK (Newcastle) doctor succeeded to restore normal pancreas insulin and glucagon regulation permanently for (new?) diabetics and measured the VF around the pancreas before and after. It showed a 25% reduction; indicating for me where the problem may be.


    • Hi Sten!

      Thanks for your comment! There’s a lot there, and I think my time is as pressed as yours is at the moment.

      Sitll, I’m fascinated by your explanation… and the reference to the Newscastle Dr. Do you have any links where we can read more on this?


  2. is it normal for my blood glucose to rise to 150 after a meal only of protein, fat and veggies? I’m not eating VLC, but I use coconut oil. I eat veggies, one/two servings of fruit and one sweet potato. Should I be concerned? Why does this happen? I though this “physiological insulin resistance” only happened to those who do VLC and have high fasting blood sugar. My fasting blood sugar is always 70.

    • I think what you get is perfectly normal and has nothing at all to do with PIR.
      The the food you listed contains a sweet potato and 1 or 2 fruits, suspected culprits. Suggest you leave out all of that for ONE meal and measure BS one hour after and compare with as now.
      Guess you will then be much closer to 100, implicating those carbs.
      Then add back one apple and see if you can tolerate it, and so on.
      Add salad and other greens, but skip store bought salad dressing and/or sauces in bottles as they are often packed with sugar! Real olive oil and vinegar instead.
      And if you don’t feel full add some (molten) butter on the protein which also enhances taste. Same for molten cheese….
      Good Luck!
      Google postprandial blood sugar track your plaque to see how the method above is used by a cardiologist to actually reduce arterial plaque!

  3. As far as I can tell, this notion of a low-carb diet inducing insulin resistance in peripheral tissues is an internet myth that is propagating across keto-websites. The list of references you provide mostly contains blogs, and 2 of the scientific papers (Borkman et al. and Bisschop et al.) both reported no change in peripheral insulin resistance (however, Bisschop et al. reported an increased hepatic insulin resistance). Read the papers and not the echo-chamber blogs.

  4. Hi Michael, I just wanted to say that after losing 6kg in 8 weeks by following my own low carb or virtually no carb diet, I was delighted I had also brought my cholesterol reading down from 6.4 to 5.2. I was however shocked and upset that my blood sugar had risen from 5.3 to 6.4. I was dumbfounded because I have never been healthier, and even my running time has lessened. I started reading about ketosis and low carb of which I knew nothing about, but now believe my high sugar reading must be due to my diet. It has frightened me enough though to start eating carbs again because I can’t figure out if it is ok to be in a constant state of ketosis or if I will do damage in the long run. I do feel cheated though that I finally found a diet that worked for me, but might also be bad for me. Thankyou for your article which I found very interesting.

  5. You need to cut down your evening proteins to achive better morning blood sugar. I am 68 years old and had same experience as you: after about 6 months weight stalls and morning blood sugar way too high.
    I believe it is the fat around my organs that is still left. By cutting protein -replace with fat – the system can be restored I think, but not 100% sure. Jimmy Moore did it at least, but combined with hard work outs.


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