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 you 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.

Resources