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Intermittent Fasting, Cortisol and Blood Sugar


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There’s been a lot of discussion about the benefits of intermittent fasting (IF) in the paleo community lately. Paul Jaminet mentions it’s role in boosting the immune system in his book, The Perfect Health Diet, and IF can also be helpful for those trying to lose weight and tune their metabolism.

From an evolutionary perspective, intermittent fasting was probably the normal state of affairs. There were no grocery stores, restaurants or convenience stores, and food was not nearly as readily available or easy to come by as it is today. Nor were there watches, schedules, lunch breaks or the kind of structure and routine we have in the modern world. This means it’s likely that our paleo ancestors often did go 12-16 hours between meals on a regular basis, and perhaps had full days when they ate lightly or didn’t eat at all.

So, while I agree that IF is part of our heritage, and that it can be helpful in certain situations, I don’t believe it’s an appropriate strategy for everyone.

Why? Because fasting can elevate cortisol levels.

One of cortisol’s effects is that it raises blood sugar. So, in someone with blood sugar regulation issues, fasting can actually make them worse.

I’ve seen this time and time again with my patients. Almost all of my patients have blood sugar imbalances. And it’s usually not as simple as “high blood sugar” or “low blood sugar”. They often have a combination of both (reactive hypoglycemia), or strange blood sugar patterns that, on the surface, don’t make much sense. These folks aren’t eating a Standard American Diet. Most of them are already on a paleo-type or low-carb diet. Yet they still have blood sugar issues.

In these cases, cortisol dysregulation is almost always the culprit. When these patients try intermittent fasting, their blood sugar control gets worse. I will see fasting blood sugar readings in the 90s and even low 100s, in spite of the fact that they are eating a low-carb, paleo-type diet.

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That’s why I don’t recommend intermittent fasting for people with blood sugar regulation problems. Instead, I suggest that they eat every 2-3 hours. This helps to maintain stable blood sugar throughout the day and prevents cortisol and other stress hormones like epinephrine and norepinephrine from getting involved. When my patients that have been fasting and experiencing high blood sugar readings switch to eating this way, their blood sugar numbers almost always normalize.

I don’t think eating every 2-3 hours is “normal” from an evolutionary perspective. But neither is driving in traffic, worrying about your 401k, or staying up until 2:00am on Facebook. The paleo template is there to guide us, but it’s not a set of rules to be followed blindly. This should also be a reminder that there’s no “one size fits all” approach when it comes to healthcare. Successful treatment depends on identifying the underlying mechanisms for each individual and addressing them accordingly.

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  1. Hello I want some advice, I’m a thin type 2 diabetic (5’4 134 lbs) , very new to the “Keto” diet, I’ve been on it for 3 weeks and emedietely saw my glucose go down, used to be in the 300’s high sugar levels, now currently down to the 140’s max, but anyway is intermittent fasting recommended for type 2 diabetics, I workout 3 times a week in the mornings on an empty stomach since 8pm the day before, I workout for hr and a half ( weight resistance and running intervals) I feel great so far and I know I still have work to do, eventually my goal is to have fasted sugar readings under 100, but anyway another question, when I workout my sugar levels tend to go up, by being on a low carb diet, will my body eventually switch and start lowering my sugars? And if so for how long and if not is there anything I can do to stop this from happening?

    • Arod. Question # 1. Intermittent fasting is recommended for Type 2 diabetes. It should reverse the disease. Keep in mind that your fasting blood sugars do not only reflect the carbs you are eating, it also calls into play gluconeogenesis wherein morning blood sugars are elevated due to the action of cortisol causing the liver to make glucose out of proteins and fats. Intensive exercise will raise blood sugar also, and this also involves pathways other than carb restriction. I don’t really understand your second question. On a non-ketogenic diet, your sugar levels go up, but on a low carb diet will your body starts lowering blood sugar levels and how can you prevent this?

      I understand the goal of ketogenic diet is to train into fat burning as opposed to carb burning as a source of energy. Since you are already lean, you may want to modify the ketogenic diet so it works better for you, since you don’t have that much fat to burn. Iintermittent fasting is good for “resetting” and unbalanced immune or hormone system. Above all, eat high quality food and space it such that during the time you are eating, you have enough fiber, carbohydrate, and protein in your last meal so that you are not triggering high cortisol levels during your fasting period. The point of fasting is not to starve, its just supposed to reset mechanism that have gone haywire for some reason–usually bad food.

      • Thank you Gloria I will definitely take your advice in regards to my Keto diet. I’m sorry about my 2nd question, but you pretty much answered it. But you know what was weird is that I felt I knew more about my type 2 disease than my Dr. He was telling me that the only way to lower my blood glucose would be by medication and maybe in the future get some insulin. When he said that I knew he didn’t understand my disease like me… From what I know is that too much insulin would make things worst, but anyway we did some blood test today and i don’t expect good numbers since I just barely started my Keto diet 3 weeks ago but I will be seeing him back in 3months. So far I only take metformin 1k ml 2 times a day (1 morning and 1 night) and 1 baby aspirin. I hope that with my momentum I will prove my Dr. Wrong and will soon not need medication to lower my gluccose levels, I have started eating big meals on my eating window low carbs high protein, another thing, my Dr. did mention that I shouldn’t worry about eating too much protein, that if anything I should make that a priority since my diabetes triggers my body and supposedly that’s why I’m a thin type 2. He said my body needs more insulin, but I say I just need to be more insulin resistant, I was just so disappointed how quick my Dr. was add more medication vs letting me try to fight this naturally but anyway thank you once again, I truly appreciated and I will keep an eye on that cortisol as well, I feel awesome so far, thank god I haven’t had any complications yet.

        • Hi Arod. Im amazed that you are diagnosed with diabetes 2 at all since you are lean-5.4 134 lbs and working out. Unless you were eating really bad food, there must be something else going on to get your blood sugar up into the 300s. I think you will see results soon if you adapt to a plan of intermittent fasting. Unless you have other reasons for going ketogenic, I would even out to a more balanced diet — leafy greens in the carb category at least. Most nutrients are in vegetables and fruits so if you don’t eat any, you can set yourself up for some nutrient deficiencies. Ive found when doctors start loading you up with drugs its time to move on. And when they start suggesting surgeries you don’t need-run!

          Don’t know what the baby aspirin is for. It may do more damage than good. And insulin for a type 2 diabetic is like prescribing alcohol to an alcoholic. Its the last thing you need. Insulin use can lead to “double diabetes” you lose your a bility to make insulin and become both Type ! and Type 2 at the same time. http://consults.blogs.nytimes.com/2010/02/01/a-hidden-danger-of-an-aspirin-a-day/?_r=0. Note. I am not an M.D. I am an anthropologist and I do have diabetes (or did have before intermittent fasting). So for what its worth … here’s hoping next time you will be report to us on your good health!!

          • Thanks Gloria and I will definitely keep you guys posted on how I will overcome this disease. But as far as how I caught this was hereditary (Dr. Explained) because both of my parents are diabetic and eating a lot of fast food must have triggered something in me.

            • Arod. Recent studies in epigenetics show that genes (as in Type 2 diabeltes) allow but do not determine a disease pathology, so saying that you have Type 2 diabetes because of your genes is a cop-out. its not like blue eyes. The reason you have diabetes (Type 2) is from your own behavior and environmental pressures. And you can recover from the disease by learning to eat nutritious foods (instead of nutrient depleted and toxic foods), and getting a moderate amount of exercise. There is probably a psychological component in there also. A lot of it is just learning to respect your own biology. Good luck.

              • Sometimes things ARE genetic and while we can make modifications to optimize our health, telling an active, lean individual that they’ve done something to cause their diabetes is very unhelpful. Despite a very careful diet, I have blood sugar issues that have amplified during my pregnancy. My doctor isn’t concerned because I “passed” my OGTT, but just barely. Once I started monitoring myself with my glucometer, I learned that my fasting glucose is always between 90-95 (it should be in the 70s while pregnant) and very low carb meals still bring me up to 120ish for hours – even after 3-4 hours sometimes. I reduced my carb intake from 100 grams per day to 50-60 grams per day and took out all starches. I keep 1 serving of berries a day just to stay sane. If I eat anything carby (yes, I mean the good ones), my blood sugar spikes into the 140 range and stays there for a while before making me feel sick and shaky. I didn’t cause this by eating too many bananas and sweet potatoes. It’s more likely connected to a) my reaction to pregnancy; and b) my mother’s daily tray of butter tarts when she was pregnant with me (resulting in insulin resistance from day 1). I also have issues with high cortisol which I am sure contributes and which I am working on.

                • I agree with Sarah, especially about the alcohol. I think the major problem here is that we are worried about blood glucose, when the real problem is insulin–too much of it. But we have no way to measure it.

  2. Hi, I am a 44 yo female dx’ed with late onset congenital adrenal hyperplasia in Sept of 2009, I have done search after search and haven’t found any information telling me if I should or should not be doing IF.
    My adrenals do not make much cortisol, it all goes to androgens which is why I have had a higher testosterone level all of my life. I was on prednisone for a few years but decided to wean off of it because I was not seeing any benefit of being on it.
    I have been doing IF for almost a year now. I was seeing great results at first but I am back up about 5-10 lbs over my maintenance weight. I am 5’5″ and right now weigh about 125 which is ok with me I just don’t want it to get any higher. I also have hashmoto’s thyroiditis.
    So my question is should I NOT be doing IF with this condition? Or can you point me in the right direction to do more research?
    Thanks so much.

    • I have the same diagnosis, but no thyroid issues. In paleo code he does not suggest doing IF for thyroid issues. Do you trend toward low blood sugar or symptoms of low blood sugar? For then you would want to eat every 2-3 hours. The only supplements that worked for me was Chinese medicine….i did all the adaptogenic herbs and stuff for cortisol there was…but that did not work for me, and many made me feel worse.

  3. I’ve been doing IF for about 2 years and started on a ketogenic diet in Jan 2015. I have noticed my FBG to be in the 85-100 range in the a.m. But my Hba1c just tested at 4.5 so I have a hard time seeing that I’m insulin resistant.

    I’m no expert, but I’m not so alarmed given these facts, especially given that my BG will continue to drop throughout the morning until I break my fast. I see something in the range of mid 50s to high 60s by that point, depending on when I eat.

    this lays out an argument that this higher, early morning FBG is a natural adaptation when one gets adept at metabolizing fat: http://high-fat-nutrition.blogspot.com/2007/10/physiological-insulin-resistance.html

    It’s intuitive to me that my body has adapted to a low-carb, fat burning state where I might fast 16-20 hours and even do an intense workout in the middle by scrounging up or sparing glucose. I don’t see how this is “insulin resistance” when overall there’s never that much glucose floating around in my blood stream (HbA1c test shows that). It more like my body has a plan B now that it has the option to burn fat or use glucose.

    There’s the cortisol angle, I suppose, which might mean that I’m unduly stressing my body, so it’s something I intend to watch. I’m probably going to play with adding some more carbs in a dinner more consistently to see what that does to FBG….

    • Tony. I like the idea of high FBG driven by cortisol as Plan B.
      I am type 2 diabetic and my A1c’s so far during intermittent fasting were 5.4 and more recently 5.7, at the same time my FBG hs gone haywire 170 or 180 on some mornings. The IF plan Im using to the daily window routine — I eat between 10 and 4 pm. This was a problem and this is when the high FBG occurred. So now Im shifting to finish eating later in the day and fasting later in the morning. I don’t have the results yet. I am hyperthyroid. I don’t see a good reason not to use a mild form of IF with hyperthyroid. i am losing some weight, but it is not excessive. And I am determined to reverse my diabetes. Somehow I think if I get rid of the diabetes, I will also get rid of the hyperthyroid issue. I never have low blood glucose on my monitor, but I still get a radical cortisol surge with gluconeogenesis, running morning fasting blood sugars sky high.

      • I have always had high morning blood sugars, whether my A1C was low or not. I find that eating something around 10 at night lowers the morning BS a great deal: normally 150 or above – this morning it was 110. The numbers have really come down with the keto diet. I starter IF last week so I hope to see a big improvement in the BS levels.

        • Susan. I think you will see amazing results with intermittent fasting. The problems you may encounter are high fasting blood sugars due to morning cortisol. Hunger isn’t a problem after a few days. While some people recommend eating frequently –every 2 or 3 hours to control blood sugar–I think this is mainly if you tend to hypoglycemia. For me that just shoots my blood sugar up into the 300 range where I dont want to be and do not feel well. I think the key to high morning blood sugar is to eat a relatively high carbohydrate meal for your last meal of the day, and include lots of fiber with it. Maybe even a fiber supplement such as inulin or glucomanan. A good guide to controlling blood sugars set off by cortisol is Christianson’s Adrenal Reset Diet. Incorporating circadian rhythms with intermittent fasting I think is the answer. I dont think eating frequent meals is a good idea for someone whose glucose control is problematical–based on my own experience.

          • Yes, eating something with a little carbs works best for me for my last meal. The night before last I ate a small nectarine (1/2 of my carbs for the day!) at the end of my window. Yesterday morning, the numbers were 88. The key is to not eat too many carbs or the numbers are higher in the morning!

  4. Thank you so much for this posting. I know that I have blood sugar regulation problems and have not known how to resolve them. I appreciate the advice to eat every 2-3 hours- makes sense to me, as I feel like I could eat all day long. The challenge is to figure out how to do this on such a restrictive diet. I am following the Autoimmune Paleo diet, the Candida diet, and also a low-oxalate diet. Based on these restrictions, there are only about 15 foods I can eat. I also have to be careful to rotate my foods because of food sensitivities. Does anyone have ideas how to eat frequently on such a restrictive diet? Recommendations for a nutritionist? I would be grateful for any suggestions. Thank you.

    • I would advise everyone to get on a low carb, high fat and protein diet. And than after a few moths, begin intermittent fasting. You will find doing both will be tremendous.

      Eat your fruits and vegetables and keep your carbs between 50-100. You will melt away fat and health problems. You will be amazed. EAT WHOLE FOODS. This is a perfect fit for everyone. Try it.

      You see, fasting gives your body a rest period, and releases all kinds of wonderful hormones, fat burning, muscle building hormones that will burn fat in your body. Doing both will keep insulin levels very low.

      • That is good advise however doesn’t always work. I have sluggish adrenals and liver detoxification and if ..even after ketogenic for years causes my blood sugar to sky rocket.

      • Sal: I guess you didn’t read this article. Chris Kresser says fasting can cause cortisol levels to increase and affect your blood glucose. Funny, I guess you missed that Chris recommends not to do fasting if you have blood glucose regulation problems and to eat every 2-3 hours.

        • But IF has been shown to improve insulin sensitivity.. so if you keep eating ever 2 to 3 hours you are not teaching your body to deal with the problem.

          • I guess it is true to teach your body about dealing with fasting but everyone is unique. First of all we don’t live in the same world as our ancestors so I believe you have to stay on top of what you eat and the chemicals around you. Fasting today is different than our ancestor since anything affects cortisol levels. I’m finding personally cortisol is a problem with my own health problems. I believe stress is a big a factor in our modern lives.

            • I sense the problem might have to do with different genetic problems associated with the pathways involved in processing glucose. The glitches may be at different points for different people, with various hormones as potentially flawed. One of the places this is being studied is the Salk Institute. So different genes for different people that control these hormones may be implicated.

              I myself am overweight and I get some activity, although in the recent winter, not nearly as much. My A1c went from 6 to 8 in this period and I have been prescribed Metformin.

              Meanwhile, I know that in the past I did well with intermittent fasting. I believe that my weight gain made me not so much unstable in blood sugar readings, as predictably lousy.

              For now, my solution will be to make sure each meal is calorically less because even if I think I am getting enough activity (say 2 miles of walking per day on average), this is not adequate to deal with the problem until there is significant weight loss. Twenty pounds off, if carefully maintained (not like the last time I did this), will help. Also, probably some vitamin supplements. I know that my family has a lot of type 2 – my grandfather, mother and half my siblings. The grandfather lived to be much older than the average in his day (83) and my mother is alive at 91 (though blind – which is soooo scary for me – it happened in a cascade when she was about 87, perhaps partly to do with a shock to her system with cataract surgery – don’t really know). We may have some “thrifty genes” which allowed ancestors to get through long periods of near-starvation. But like sickle cell anemia being protective against malaria, this kind of diabetes may have saved lives which later were shortened when food was more freely available. However in our having Type 2, my family is not so unusual for Americans since it is rising here.

              Here I am at my laptop, and the level of sitting during a New England winter is far too much to be healthy in any case. There have to be some guidelines – like getting up for several minutes of any hour for all chair-workers. One burst of exercise in the day, as we know, does not help enough.

          • I have IF’d for 3 years – skipping breakfast, fasting 16 hours a day. Every year my cholesterol gets better, and my blood sugar worse. Over 3 years it’s gone from 99 – 107 – 124. I’m going to give breakfast a shot, and maybe even eating every 2-3 hours.

      • Absolutely disagree. I have been on a strict ketogenic diet for over 100 days. My blood sugar would not come down. Then I tried intermittent fasting and the same results. There are those who do not gain control of their sugar levels. This is not a theory but my own experience, regardless how much sense it makes – IF. My blood pressure increased and my sugars would not drop. I appreciate the article because it makes sense. IF is not for everyone. I am one of those.

  5. I have a feeling that one of the answers to the increase in blood sugar might lie in Stephen Gordon’s post further up the page.

    We are broadly applying the thinking that ‘paleo’ or ‘IF’ etc diets may be helpful because they are more in line with the nutritional environment that we evolved for. It would then make sense to modify other aspects of our life in the same manner.

    Perhaps the increased blood sugar that results from these diets is actually a natural healthy response if we look at the big picture. Maybe our body is moving back towards its natural apex physiology which suits a much higher/intense activity level (hunting, gathering, fighting predators etc) than we are exposed to in modern sedentary society?

    I think Boyd-Eaton(?) had some papers on the activity levels of indigenous/paleo peoples compared to today’s society. Showing that the old “30 minutes of moderate exercise 5 days a week” was nowhere near the levels of activity required to trigger healthy cell function.

    In fact the 30 minutes thing has only ever been the bare minimum required to avoid a diagnosed sickness – which is actually a totally different goal to creating health.

    I wonder how many of the people here have introduced a lifestyle change to a fairly high/intense activity level such as Stephen Gordon’s boxing training etc alongside the IF nutritional changes?

    Also, what about the mental-emotional component of our lifestyle. If this is not also changed in a manner that honours health it can easily contribute to amplified/misplaced endocrine responses. This could also make an otherwise healthy diet appear to be unsuitable?

    Everything is connected – the way we eat, the way we move and the way we think are all interrelated when it comes to non-linear endocrine and neurological feedback loops. Helping the body make its way from high allostatic load back to homeostasis requires an orchestration application of lifestyle change.

    Hence, I wonder if it is not so much a failing of the IF diet, but an erroneous expectation that a nutritional change alone is a fix-all solution a highly complex problem… Seeking to make food a natural ‘medicine’ to fix a diagnosis, rather than seeing it as an integral aspect of a living environment which facilitates for the creation of health.

    Without requisite changes to the interdependent physical and mental-emotional aspects of life we may be compromising or confounding the IF/paleo diets elgance or effectiveness.


  6. Yes doctor, you’ve got the answer why my blood glucose is much more higher at the end of the day than when I get up during fasting.

    I’m so confused whether to take my medicine or eat my low-carb diet or what? Now I’ve got it to to eat every 2-3 hours but moderate amount of food.

    Is there some way to control or reduce cortisol during fasting?

  7. TL;DR: I’m an archaeologist. The paleo-diet is not “one size fits all.”

    I’m an archaeologist who specializes in the studies of diets of hunter-gatherers. I’d say eating every few hours is actually pretty normal. Hunter-gatherers spend a large amount of time foraging, during this time they’re snacking more or less constantly. Like, if you go out picking berries, you’re not going to snack on a few? Also, hunters would usually take food with them.

    What we have to remember is that the hunter-gatherers you see today are disadvantaged, fourth-world peoples who have been forced into marginal environments. Many of our ancestors lived in much more accommodating environments.

    Furthermore, hunter-gatherers live (and lived) in wildly variable conditions, with wildly varying diets. The Inuit eat 90% meat whereas the San eat 90% plants (give or take). If your body tells you to eat every few hours, then do it. It might have something to do with hundreds of thousands of years of your ancestry.

    • Hi Laura. I am an archaeologist, also, and thanks for setting the record straight. Our ancestors normally had plenty to eat. They did not normally spend a lot of time starving. If they did, they would not be us!

  8. Hey thanks for the post. It was very helpful.

    Over the past 3years, I have lost about 30lbs by just eating meat and vegetables with regular exercise. I am a 5’8″ male and weigh about 210lbs.

    I believe I hit a plateau. I am looking into intermittent fasting. I want to start very slow. I find that I have more bowel movement when I fast, once/week. I came to use fasting since I found that after about two weeks of intense/cardio exercise (5x/wk) and eating 3x/day, I was tired and my weight fluctuated between 205-210lbs.

    What are your thoughts?

    thanks so much again !

  9. I just switched over to a 30 day paleo meal plan from “Practically Paleo” from a typical diet high in carbs and sugars. I have PCOS and to help prevent insulin resistance I am on metformin 500mg twice a day. My question is this: I am 4 days in and seeing spikes in my blood glucose levels. I monitor with a meter as you suggested in one of your articles. I typically have very normal non-diabetic numbers for blood glucose. Now I am seeing my baseline at 93-95 and my fasting at 100. Is this typical? should I see it level out and return to my old levels if I just stick with the paleo diet?

    • . getting too much protein can work against the metformin
      by raising glucagon that increases liver-made sugar;
      remember, the magic of the Atkins diet
      in the way it lowers blood sugar and cholesterol
      is not just from being low in carbs,
      but also by being high in fat
      rather than high in protein .
      . try getting less than 50g protein per day;
      and get more gentle, low-glycemic carbs
      like greens, cabbage, broccoli … .
      — peas are a low-toxicity, nearly-Paleo legume
      and hence a good carb according to the Perfect Health Diet .

  10. I have been intermittent fasting for several years now. I stop eating at 4 pm and start again around 9 or 10. I would not eat every 2 or 3 hours — that would only run my bood sugar up. For me eating is a problem, I feel much better when I dont eat. I eat 2 or 3 small meals a day. More ketogenic than paleo. I am diabetic and hyperthyroid. I am now off insulin. A1c 5.4. So Im still working on diabetes. This summer I started having unreasonable fasting glucose readings–to 180. It turned out to be due to deydration — and a faulty blood glucose monitor. I can recommend IF as a means to deal with diabetes.

    • Hi Gloria,
      Thanks for your post. Can you clarify your IF for me? You stated that you stop eating at 4pm and you start eating at 9-10. I assume that is 9-10 AM but don’t want to assume….

      I have been doing IF from 8p-about Noon…. having my first meal at lunchtime. The morning I am drinking some bulletproof coffee. Gets me through the morning fast…

      Trying to get my morning BS’s below high 90’s. Some days it is and others it isn’t. Having quite figured out the trick yet….
      I’ll just keep on working at it.

      • hyperthryoid. No. In fact its worse. Yesterday, the M.D. recommended radiation therapy to destroy my thyroid gland. Also, high morning blood sugars continue. I like intermittent fasting. To me its simple to do, and it does keep my insulin levels low–so A1.c 5.4 tells me there is something right about the method of IF I am using. I don’t want to eat every 2 to 3 hours. It seems to me this discussion is focusing on blood sugar, when the real problem in diabetes is insulin.

    • Well this is June, 2015. The high fasting blood glucose problem continues. I replaced the monitor, and I am trying to drink more water. My fasting blood sugar is sometimes as high as 180. Clearly there are endocrine complications. In addition to the not controlled diabetes, hyperthyroidism has kicked in. I didn’t need to lose weight, but I did lose 20 lbs –and atrophied muscles are starting to show. Also bulgy thyroid eyes. You would not want to meet me on a dark street at night! Houston. There is a problem! Yes I do have chronic stress, from the apartment complex next door–a blaring stereo 24 hours a day.

  11. Sigh! I eat a low-carb, ‘clean, wholefood’ type of diet (spend quite a bit of time in nutritional ketosis), and I fast daily for about 18 hours, plus a 24 hour fast weekly.

    I LOVE fasting – it gives me a sense of control, and wonderfully level energy, and for the first time in my life, I am free of cravings.

    But my blood glucose sux – fasting can be as high as 7, and I spent most of the day at around 6. It drops to 4-5 soon after eating (the strange patterns you mentioned). HBA1c has gone 34mmol/mol -> 35 -> 37 over the last year (which my Dr says it completely normal, as is my BG).

    I am very frustrated – I desperately don’t want to stop fasting and go back to feeling out of control, hungry, and like I am on an energy rollercoaster.

    • see zone diet for low-carb’er has high blood sugar:
      high levels of protein insure high blood sugar .

      • Except I’m pretty sure I am not high protein – I am a pescetarian, but my diet is largely planted-based. I worked out I am eating about 50g/day protein.

        I had a look at Zone, and why it may cause high BG – but if it was a cortisol issue then I think I would be experiencing loss or muscle mass, possible weight gain etc, but I’m 14% body fat, and pretty strong, so I’m not convinced it is that. Interesting trying to work it out.

        • I wasn’t referring to your cortisol;
          the zone diet says dietary protein raises your glucogon hormone levels
          which cause your liver to produce more glucose;
          you don’t need 50grams per day unless you’re doing major weightlifting work .

          • PhT. – I believe that this is what occurs with me. If I eat more protein than 50, my morning FBS seems to be elevated (high 90’s to low 100’s). If I eat limted protein the day before, I have been getting FBS’s in the 80’s. I am finally getting to the bottom of this. I think I am very sensitive to carbs and protein. Too much protein is not what is needed for me.

    • Fasting and consuming high fat only gets very old. If I fasted as much as you did, I would be ripped to shreds.

      You never want to totally get rid of wholesome foods, like vegetables and fruits. I understand fruits have sugar, but eat small amounts.

      I seldom use ketosis. I like staying between 50-100 carbs per day.

      I like ketosis in theory but giving up my fruits, can’t do it. Wholesome nutritional foods have too many benefits for the human body.

      Ketosis is overrated. 100 grams and below should do you well. You need some carbs to keep your body to trigger bother energy sources fat and glycogen. Have the best for both worlds just do not blow out you cabs consumption. Works for me.

    • I agree. And I think the problem is that we are using blood sugar levels to guage how our diabetes is doing–when we should have some way to measure insulin.

  12. Cortisol is a hormone that’s released when we are physically or mentally under stress (the body can not tell the difference between the two) the reason that blood sugar increases is because your body thinks you are about to be physically active. So it provides glucose for your muscles… Even if you aren’t going to use them

  13. I find this very interesting. I believe that I am similar. If I don’t eat for a long period of time, my fasting BS is high 90’s to 110…. When I eat prior to going to bed, my fasting BS is better. I think I am going to have to do some more reading on this to get a better handle on this. I had no idea. Thanks everyone for sharing your stories.

  14. Thanks for these fabulous posts! It is refreshing to hear some data from a practitioner who is NOT just pushing pharmaceutical solutions. I am attempting to lose weight low-carb style. I know I’ve been insulin resistant for years. After a week and a half averaging 14g of net carbs per day, I’m only losing a small amount of weight, and my blood sugar is hovering between 95-100 (fasting and after meals). Why would blood sugar remain so high, and why am I not seeming to stay in ketosis with heavy carb restriction? Thanks!

    • I’m anxious to hear some responses as I am in the same boat as you. I don’t think I am as low as 14 for carbs each day…. that’s pretty incredible.

    • . if 14g of carb hinder ketosis,
      consider less-glycemic carbs, eg, for 2 weeks
      try your only carbs are a soluble fiber supplement
      and remove conditions causing insulin resistance
      like caffeine, alchohol, other meds .
      if stress or lack of sleep is causing
      too much cortisol and not enough DHEA,
      do weightlifting or peak resistance isotonic exercises .

    • moderately educated theory here:

      protein, especially in excess(high) amounts as in many low carb diets can undergo the gluconeogenesis pathway. If you were eating a traditional/standard american high carb and relatively frequent meal schedule prior to switching to low carb but high protein, perhaps the body is trying to do what it’s used to – using the enzymatic pathways that are ramped up – burn glucose for fuel. To get the body shifted to fat burning, we have to eat fat and moderate/adequate protein (approx under 100 g perday) and fasting should help with that, but it takes some time for the body to build up the fat/ketone burning enzymes. Apparently, I believe I heard in an interview with Tim Noakes, full ketoadaptation can take years.

  15. Hi Chris:
    This sounds like me! I’ve had reactive hypoglycemia for years. Now I’m dealing with post-menopause while on bio-identical hormones. Meanwhile, my fasting blood sugar is hovering around 100, my cholesterol is over 200 even on a statin & I just feel old & gross. I’m 51 & weigh 170. Yuck! I know eating my husband’s BLT, tuna melt or chicken parm w/ garlic bread along w/ several glasses of red wine on a Saturday night aren’t helping! I know I need to exercise but I feel so wiped out after work & a 40 minute drive. I also have a spouse & an 11 year old (which is great) but does take some time. Sorry this is so whiny but it’s been hard to find sound realistic diet & exercise advice for women my age! I’m having a hard time with sustained motivation! Thanks!

    • I think it is very difficult to focus on personal habits and needs, when your life is focused on others. Getting healthy is about personal responsability –and that is not an easy thing to do when your life is oriented to responsability for others.

    • Having cholesterol over 200 is not a bad thing , as long as the HDL / LDL ratio is right . We need cholesterol to make vitamin D and many hormones , as long as we are consuming healthy fats ( butter and eggs included ) thats fine. A great book to read on the subject is ” The Great Cholesterol Myth “.

  16. hey everyone- i have a question. can anyone tell me why i get horrible hypoglycemia, weight gain, and just feel horrible when my cortisol is LOW? i have had cushings disease, and when my cortisol is high i immediately lose weight, feel wonderful, and my blood sugars normalize. this is the opposite of what should be happening. any advice is greatly appreciated. i recently had to have my adrenals removed because of the high cortisol- and the cure from cushings and the “low cortisol” has brought on serious weight gain, blood sugar issues, and pre diabetes. it is insane. any a dice is greatly appreciated.!

    • That’s really strange because usually high cortisol is what causes weight gain and high sugar.

    • if you felt great, why remove your adrenals? just kidding 😉
      too much cortisol is like too many pain killers …
      you feel great but you die young .
      . usually people who feel bad (as from low cortisol)
      abuse food — which would be the likely cause of your
      “serious weight gain, blood sugar issues, and pre diabetes.”
      . it’s not high cortisol that causes blood sugar instability;
      rather, insulin rebound from a glycemic (grainy sugary) diet
      (which mean having too high then too low of blood sugar)
      causes cortisol to be raised in order to
      protect the brain from low blood sugar
      (cortisol causes insulin resistance in the body
      so there is a guaranteed supply of sugar for the brain).

    • From what I’ve learnt on my MSc in personalised Nutrition, when your blood sugar levels are low, your body needs to pump cortisol & adrenaline from your adrenals to raise your blood sugar levels, so if you can’t produce enough cortisol to do this, your BS will remain low. It also uses glucagon from your liver to turn glycogen into glucose but if glycogen is depleted through low carb diet then you won’t be able to increase your blood sugar that way either…just a thought

  17. I didn’t hear any mention of time frame. Yes, glucose may temporarily be worse, but is blood pressure when you exercise. What matters is the long term benefit.

  18. Hi thee, Just got diabetes, eat no carb or sugar for 3 weeks now. My FBS was 283, now when I test myself in the morn it’s 220-240. As soon as I eat something it drops to like 178. & steady or drops more throughout the day to never as low as 173 so far. Still working on that. But my post meal never spike more then 20 points. Sometimes it only spike 2 points. I try to always snack & morning readings is still high. Fasting about 12 hrs. Please help. Any ideas? Or do I need to be patient, it’s been only 3 weeks. And am I lowering the numbers fast enough? Is hardly any post meal spike more important then the over all high number.? HELP!

    • I believe waking up with high glucose
      is a sign of too much protein;
      get most calories from monounsaturates or mct oil,
      get a little fish oil, and cut back on vegetable oils (omega-6).
      . get most protein from raw yolks
      (Eggland’s Best or pastured eggs).
      . get carbs that increase insulin sensitivity
      like greens and brocolli . puree the hot greens in olive oil .
      take supplements that enhance metabolism:
      carnitine, alpha lipoic acid, Q10, mct oil .
      . if that wasn’t working for me,
      I would see my doctor for metformin (Glucophage).
      google this:
      site:lef.org metformin

      • PhT, who are you and what is your background/what are your credentials?

        You’re giving out a lot of advice here and IME not all of it is good.

        Be careful what you say to people.

        • . I get the thread is about
          hyperglycemia due to high-stress cortisol;
          but if a person is still not getting results,
          then according to the zone diet’s Dr.Sears,
          high protein will raise your blood sugar levels .

    • It takes longer than 3 weeks, and insulin levels, not transient blood sugar levels are what’s important. Blood sugar is just a down stream event. Hang in there and stick with the program.