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When Your “Normal” Blood Sugar Isn’t Normal (Part 1)


In the next two articles we’re going to discuss the concept of “normal” blood sugar. I say concept and put normal in quotation marks because what passes for normal in mainstream medicine turns out to be anything but normal if optimal health and function are what you’re interested in.

Here’s the thing. We’ve confused normal with common. Just because something is common, doesn’t mean it’s normal. It’s now becoming common for kids to be overweight and diabetic because they eat nothing but refined flour, high-fructose corn syrup and industrial seed oils. Yet I don’t think anyone (even the ADA) would argue that being fat and metabolically deranged is even remotely close to normal for kids. Or adults, for that matter.

In the same way, the guidelines the so-called authorities like the ADA have set for normal blood sugar may be common, but they’re certainly not normal. Unless you think it’s normal for people to develop diabetic complications like neuropathy, retinopathy and cardiovascular disease as they age, and spend the last several years of their lives in hospitals or assisted living facilities. Common, but not normal.

In this article I’m going to introduce the three markers we use to measure blood sugar, and tell you what the conventional model thinks is normal for those markers. In the next article, I’m going to show you what the research says is normal for healthy people. And I’m also going to show you that so-called normal blood sugar, as dictated by the ADA, can double your risk of heart disease and lead to all kinds of complications down the road.

The 3 Ways Blood Sugar Is Measured

Fasting blood glucose

This is still the most common marker used in clinical settings, and is often the only one that gets tested. The fasting blood glucose (FBG) test measures the concentration of glucose in the blood after an 8-12 hour fast.

It only tells us how blood sugar behaves in a fasting state. It tells us very little about how your blood sugar responds to the food you eat.

Up until 1998, the ADA defined FBG levels above 140 mg/dL as diabetic. In 1998, in a temporary moment of near-sanity, they lowered it to 126 mg/dL. (Forgive me for being skeptical about their motivations; normally when these targets are lowered, it’s to sell more drugs – not make people healthier.) They also set the upward limit of normal blood sugar at 99 mg/dL. Anything above that – but below 126 mg/dL – is considered “pre-diabetic”, or “impaired glucose tolerance” (IGT).

Oral glucose tolerance test (OGTT)

The OGTT measures first and second stage insulin response to glucose. Here’s how it works. You fast and then you’re given 75 grams of glucose dissolved in water. Then they test your blood sugar one and two hours after. If your blood sugar is >140 mg/dL two hours later, you have pre-diabetes. If it’s >199 mg/dL two hours later, you’ve got full-blown diabetes.

Keep in mind these are completely arbitrary numbers. If your result is 139 mg/dL – just one point below the pre-diabetic cut-off – you’ll be considered “normal”. Of course this is perfectly absurd. Diabetes isn’t like catching a cold. You don’t just wake up one day and say, “I’m not feeling so well. I think I got a bad case of diabetes yesterday.” Like all disease, diabetes—and diabesity—is a process. It goes something like this:

malfunction > disease process > symptoms

Before your blood sugar was 139, it was 135. Before it was 135, it was 130. Etcetera. Would you agree that it’s wise to intervene as early as possible in that progression toward diabetic blood sugar levels, in order to prevent it from happening in the first place? Well, the ADA does not agree. They prefer to wait until you’re almost beyond the point of no return to suggest there’s any problem whatsoever.

[End rant]

The other problem with the OGTT is that it’s completely artificial. I don’t know anyone who drinks a pure solution of 75 grams of glucose. A 32-oz Big Gulp from 7-11 has 96 grams of sugar, but 55% of that is fructose, which produces a different effect on blood sugar. The OGTT can be a brutal test for someone with impaired glucose tolerance, producing intense blood sugar swings far greater than what one would experience from eating carbohydrates.

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Hemoglobin A1c

Hemoglobin A1c, or A1c for short, has become more popular amongst practitioners in the past decade. It’s used to measure blood glucose in large population-based studies because it’s significantly cheaper than the OGTT test.

A1c measures how much glucose becomes permanently bonded (glycated) to hemoglobin in red blood cells. In layperson’s terms, this test is a rough measure of average blood sugar over the previous three months.

The higher your blood sugar has been over the past three months, the more likely it is that glucose (sugar) is permanently bonded to hemoglobin.

The problem with the A1c test is that any condition that changes hemoglobin levels will skew the results. Anemia is one such condition, and sub-clinical anemia is incredibly common. I’d say 30-40% of my patients have borderline low hemoglobin levels. If hemoglobin is low, then there’s less of it around to become bonded to glucose. This will cause an artificially low A1c level and won’t be an accurate representation of your average blood sugar over the past three months.

Likewise, dehydration can increase hemoglobin levels and create falsely high A1c results.

The “normal” range for A1c for most labs is between 4% and 6%. (A1c is expressed in percentage terms because it’s measuring the percentage of hemoglobin that is bonded to sugar.) Most often I see 5.7% as the cutoff used.

In the next article we’ll put these “normal” levels under the microscope and see how they hold up.

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Join the conversation

  1. Hello… new to the board. I read your articles on blood sugar tests and abnormalities and have a question. My a1c is normal– below 5, but my fasting numbers are 95-105, and I have had postprandial numbers from 155-200, mostly 160-180, one hour after eating. Closer to 140 at 2 hours. 2 readings in 2 weeks above 200, with some dizziness and a great desire to lie down. I have been very tired and have had bouts of frequent urination, heat intolerance, and dizziness for a few years. I have had no appetite or thirst for about 6 months, and have lost weight (from 115 to 100 pounds). I visited an endocrinologist that tested me for autoimmune diabetes and the test was negative. He does not think I have an endocrinology problem and hopes I feel better. My thyroid is normal, and my ANA is negative. The only abnormal tests I have had are low potassium, low alk phos, and low ck. Are the sugar numbers abnormal and should I go back to my PCP?

  2. I know I have very high cortisol levels however I am also concerned about my sugars. Tonight I conducted an experiment. I had 5 large buttermilk biscuits with artificial butter spread and a cup of skim milk. Total carb count 138 grams consumed in about 15 minutes.
    These are my glucose readings:
    1 hour later 128
    2 hours later 132
    3 hours later 129

    What does this mean? It seems like an awful lot of carbs but my numbers didn’t get very high but also didn’t drop very much.

  3. Hi Chris,

    I came across this article about the potential connection of antibiotics to dysglycemia. Is the possible mechanism of action increased gut permeability due to dysbiosis? Just trying to put the pieces together and understand the full impact of modern pharmacy on our ancient body systems.

    Thanks for all you do! You really are my “does this make sense” meter!!


  4. I am so glad I found this! I am 27 weeks pregnant and was recently diagnosed with gestational diabetes. I also have pregnancy induced hypertension and take labetalol to control the hypertension. I am also over 40 and this is my 5th pregnancy. My last pregnancy was over 10 years ago. Body shock and old age I suppose. My question is: Does the labetalol affect the outcome of the blood glucose test? My A1C was 6.2% and my average 3 month level @ 135. I was not prediabetic before. All blood work always came back normal. My doctors are more interested in numbers at this moment (which is ok, we want to keep the baby safe) but are refusing to tell me if labetalol may be a contributor to the higher glucose levels.

  5. Hi Doctor,My name is Feizel i am 55years old,I have blood pressure which is severe,meaning my last check up it was 199/132 and my sugar level is 19.2,please can u advise me on what i should be taking.My GP recommended Ridaq25g and Glycomin.Need advise please because i only just found out that i have blood pressure and a diabetic.Thanks
    Kind Regards

  6. After a good all american dinner w/ potatoes filling my meter test in 216. and it stays on a declining high for 4 – 5 hours then it is 128 with no exercise. With exercise it is 109. My red blood cells are over the top at 48.3.

  7. I’ve had a lot of similar things going on as the rest of you. My A1C was 5.8. I bought a glucometer and have become obsessive-complusive about checking my blood sugar. I have very high cholesterol. LDL 191. HDL 65. Tri 57. I was eating veg diet but I feel much better eating more protein. My blood sugar is very affected by carbohydrates. I had a hot fudge sundae last week and my bg level went up to 184 and dint go down for several hours. Fasting is usually 84-96. Post-prandial, deending on what I eat, it can be around 110 and as high as 184 if I eat high carb. I’m just wondering if I have prediabetes or if these readings are ok. Maybe I should just really watch carb intake. My peak blodd sugar sometime doesn’t happen until 2 hours after a meal and then it starts to come down. If I take cholesterol meds will it bring down my blood sugars?? Thanks for the comments.

  8. Hi Kris
    I haven’t yet been diagnosed with diabetes but have had some odd numbers. My doctor was less than helpful and just suggested that I continue to eat normally. About a year ago I started to drink huge amounts of water and felt exhausted after eating and generally low energy all the time. I am a 60yr old female, weight 53kg height 5’4”, have a demanding physical job. Diabetes in the family. Anyway, my HbA1c was 6.2, fasting about 4.5. With no help from the doctor I immediately cut all sugar in my tea, never was a big cake/biscuit/choc eater anyway. Next A1c was 6.3, so I cut more carbs. next 6.3 again, cut carbs down to about 50g per day. Next A1c was 6.0 so it has come down but has taken a year to do it, but my fasting is now down to about 3.2. If I eat any grain products I spike quite badly. Why should my A1c have taken so long to come down when the fasting is so low? My c-peptide is within normal limits although on the low end of normal. I appreciate that you cannot give a diagnosis, but from your experience do you think that these numbers might suggest early stages of LADA?

    • Veronica- I recently had some joint pain and visited a rheumatologist. She asked me if I was frequently thirsty and when I replied’ yes’ she tested me for Sjogrens Syndrome. I assumed my very dry mouth/increased thirst was from high blood sugar which has been high recently. Sjogrens Syndrome can also cause fatigue and joint pain- and is common in women over 40. Check it out. .

  9. Hi
    I really need your help! I’ve been struggling with doctors taking my test results seriously and would like your input. I’ve had high igf1 and high growth hormone levels but suppressed during the ogtt test and was told I was just abnormal and would have to wait it out. My a1c was actually low 3.8 and average gluclose in the low mid 60s (I am not diabetic). My endo said this was actually good, despite my feeling awful all the time, because he sees such high readings normally. I also have had decreasing low platelet volume.
    Any input you could give to me would be greatly appreciated

    Thanks and keep up the good work!!

  10. Hi Chris, Thank you for your valuable insights on a myriad of issues. I’m wondering if you know how effective l-arabinose is as a “sugar blocker”. My friend is thinking of trying a range of products from a company called Ludaxx. They are called F21 (which contains l-arabinose and a polysaccharide “PSK”), a KonLi (a herbal tea) and PEARL. They are meant to aid in blood sugar control, weight loss and increased energy. I would value your opinion on them. Thank you.

  11. Hey,

    Will I be considered a diabetic if my A1C was 7% but my blood glucose is 84 before eating a meal?

  12. Hi Chris,

    Would really appreciate your thoughts on weight loss. If I am considered a “pre diabetic” now and weigh 110kg, am I really ably to reverse the chance of diabetes if I loose 15kg and bring my BMI into normal range or is the damage already made? Already, I have changed my fasting BS levels from 5.8mml mml to 4.9mml but that could just be a change in food consumed and increased exercise. Also, after fasting and 45 minute run, my blood glucose went from 4.9 to 7.5 breifly post run…. is this normal for non diabetic? I really would appreciate if you can explain this to me further.

  13. Hello Chris,
    Thanks so much for your great web site and kindness in helping others.

    Based on what you mentioned regarding anemia and falsely low A1C, my situation is rather odd. I am 50 yrs old, a vegan for 24 years, and have always had low hemoglobin with no other symptoms, great energy and great lipid profile. (As an interesting aside, my mom, a big meat eater, has always also had low hemoglobin as well). However my A1C is elevated, with a fasting glucose of 94. So while the FBG is somewhat normal (though I know you said this is higher than than the “real” normal), I would expect my A1C to be low (or falsely low) due to the anemia, since the FBG is in the somewhat normal – or at least not way out of normal -range. I also have low B12 and wonder if I get that up to normal levels could I fix this situation and maybe this is affecting the A1C reading? ( I dont have the A1C number yet but was told it is “elevated”).

    Thanks so much for any thoughts/suggestions!


  14. Confused with reading my BG tests !
    I had in the LAB the FBG 126 and my A1C 5.4%. My doctor told me I was diabetic while I was in shock and disbelieve because I never have any taste for sweets, never I’m thirsty nor I did have any other symptoms diabetes has. For one month I did BG tests home, 3-5 times per day.

    Results from my home test:
    FGB : from 84 to 118, most of them were under 110
    2 hrs after breakfast : from 100 to 126 ( 1 slice of bread, butter, honey, butter, yougurt)
    2 hrs after lunch : 84- 120
    2 hrs after dinner (84-135 ) most of them were under 125.

    Every time I have a beer for dinner, I get my FGB under 85. My lowest ever has been 70.

    Exceptions (2 in total):
    1) 2 hr test after dinner did go 151, after 45 mins good exercise did go to 70 !!!!
    2) 1 (one) hour test after eating pizza for dinner, did go 172 but after 2 hrs did go back 116. I did not exercise to see how well my body would work.

    Am I diabetic ?
    Thanks in Advance,
    A NoVaGuy.

    • This is something you need a clinician to look at firsthand, and there are other factors to consider. Your FBG puts you in the pre-diabetic range (if above 99), but your post-meals look fairly normal with the exception of the readings >120 at 2-hours. The one-hour reading of 172 definitely indicates problems with glycemic control. I would run some more 1-hour tests. Seems you may have problems with your first-phase insulin response.

      • Chris,
        I appreciate your help. You articles (part 1 & part 2 about prediabeties) really made me have another look of understanding diabeties. Being in conservative side of the GB level only helps.

        By coicidence, yesterday was my 3 months check test for FGB. It was 87 while my A1C 5.7%, up from 5.4%. My FGB was consistant with my home tests for the last few weeks but I can’t figure out the cause of A1C going up. Even though under the Keiser Permanente result shows as a normal range, definately I’m keeping a close eye on it, considering it a pre-diabities level.

        ALSO I have to mention and I want to share with everyone, not a surprise for most of you but I have figured out that exercise REALLY, REALLY helps a lot. For the last few weeks, FBG has been under 88, 1 hour tests have been less 110, almost all of of them less than 90. I haven’t cut what I eat but how much I eat. I eat ‘normal’ sizes, probably twice as big hospitals normal sizes are. With exercise I can keep my GB always under control. (regardless if I eat honey, whole weat bread and soups, fruits, pizza, butter& bread, yougurt, cheese, milk, a combination of them or whatever – I don’t eat a lot though as I used to and I eat most of the times organic food). Now I’m doing 5 tests a day and making sure that at any random test of my GB is under 120. I really hope that my experience can help someone who may overlook the excercise, as I personally did before.

        Chris, thanks you a zillion times for helping people like me,
        Regards from Virginia,

      • Hi Chris,

        I also have the same problem. My fasting BG is around @100 (97-104) and shoots to 180-200 after an hour of meal(especially dinner). But it comes back in range (120-140) after 2 hours. Do you think this OK? What action would you suggest otherwise? Please advice.

        Thanks in advance.


        • Hi Prasanna,

          I am also having the same problem as you..My fasting BG is around @100 (90-107) and shoots to 180-200 after an hour of meal(only after dinner). But it comes back in range (140-170) after 2 hours of dinner…Can you help me as to what I have to do?

  15. Here’s an odd one for you (at least I hope so)… Had blood drawn right before colonoscopy (aggressive prep…started earlier and consumes 33% more PEG 3350 just to make sure gastro didn’t have wiggle room on quality of prep)… LDLs came back elevated (expected, I stopped statins to see what weight loss would do for me…not much) and blood glucose came back darn near at diabetic levels.

    I told my GP I was obviously dehydrated. I also secretly wonder what PEG 3350 did to my metabolism of the yellow gatorade I had 8-10 hours pre-draw.

    Could dehydratation account for the blood glucose travesty? Any data on sensitivity of BG to dehydration?

  16. My BG reading has been 103, 106 once it was 136 with no medication how am I doing and why are numbers higher sometimes in the morning. Last night I was 103 the first thing today 136 I expect tonight to be 110 or so.

  17. thanks for your interesting blog.
    i just had a fasting glucose/insulin test with 75 glucose drink
    i wanted this test because after oatmeal or granola i often get a sugar crash.
    apart from the above i have no other health problems.
    my glucose reading was 5.2, then after one hour 3.8, then after two hours 2.9
    my insulin reading on the other hand was14.4, then after one hour 406.0 !!! then after 2 hrs. 216.0
    my doctor was not at all helpful in explaining to me why my insulin spiked so after one hour and my readings on the internet for hours, was not fruitful either.
    how would you interpret my high insulin peak (combined of course with my low blood sugar?).
    i thank you sincerely in anticipation.
    suzanne la rose
    hornby island
    b.c. canada

    • Suzanna, I think it’s Dr William Davis (in his book Wheat Belly) who discusses how oatmeal is has a hugely bad effect on blood sugar — even the b.s. of ‘normal’ (non-diabetic or non-pre-diabetic) folks. As delicious as oatmeal is please try switching to eggs for breakfast for a week (even hard-boiled, if you have harried mornings) and follow your b.s. to see how it goes. My back-of-the-envelope thinking would be that the insulin is ‘controlling’ the high blood sugar reaction: your blood sugar drops and drops, because your insulin is insanely high! You might look online to see if there is something about your pancreas slamming out massive doses because it’s on its last legs? But I’m not a doctor, I don’t play one on TV (or the internet); this is just something I’ve read about. Have you read around here? http://www.phlaunt.com/diabetes/ and http://bloodsugar101.com — really excellent info!

  18. I just got diagnosed , my ac1 was 6.8 today I went to get my meter and my blood sugar after eating is 116 and whne I awake it is 117, I do NOT want medication so I am trying excercise and diet, should I be more alarmed at those numbers, ny dr wanted me to immediately go on meds.

  19. Please, I am a 54-y-o woman, BMI 19.2, plant-based diet, and largely vegetarian so most of my calories come from complex carbohydrates and fats (LOTS of nuts. Really lots). Lipid profile and lipid NMR are spotless….really-truly. But, A1c is now 5.6. Post prandials are usually fine and return to < 100 mg/dl in an hour. But a.m. fastings are nearly always 95-105. Why, why, why? When I try to restrict carbs, I drop weight instantly and can not for the life of me gain it back. Why is this happening? Fasting insulin was undetectable, with a normal c-peptide. The endocrinologist told me to quit worrying…..that nothing is wrong. But I am not convinced and am actually frightened to death. Can you shed light? Thank you so much!

    • sounds to me like you are doing fantastic! the A1c is a projection of future 3 mos. i would not worry about it at all. your 5.6 is great! on my lab report, my A1c was 5.7 and it said that they want it under 5.6. so, it sounds like yours is fine! good luck
      i would incorporate some animal protein once a week if i were u. it has nutrients in it that u r not getting w only plant foods. i was a vegetarian for 7 yrs. my health went downhill until i went back to being a carnivore!