May 11, 2010

Understanding Fasting Blood Sugar

Among the most common questions people have about Type 2 diabetes is this: how can they lower their fasting blood sugar?

To answer this question in a way that will help you lower your blood sugar we are going to have to first explain why doctors measure fasting blood sugar and what it does--and does not--tell us about our blood sugar health.


Traditionally, fasting blood sugar is the value you get when you test your blood sugar after an 8 hour long fast--which is usually immediately upon waking. In a normal person this fasting blood sugar would also be the "baseline" blood sugar--the level to which blood sugar returns a few hours after every meal all day long.

However, for reasons we will discuss later on, this is often NOT the case for people with Type 2 diabetes, whose morning blood sugars may be much higher than the baseline level they achieve after meals for the rest of the day.

Doctors have for decades relied on the FPG (fasting plasma glucose) test which measures fasting blood sugar to diagnose diabetes. The reason for this is NOT that FPG test results predict diabetic complications. They don't. Post-meal blood sugar tests are a much better indicator of whether a person will get the classic diabetic complications, and the A1c test is a better indicator of potential heart disease.

But the FPG test is cheap and easy to administer, hence its popularity.

The value most of us would find much more helpful in assessing our health is not fasting blood sugar but something else: the number of hours a day our blood sugar spends elevated over the level known to cause complications, which is roughly 140 mg/dl (7.7 mmol/L).

A person can wake up with a FPG of 130 mg/dl (7.2 mmol/L), but if it drops after breakfast and most hours of the day are spent with blood sugars that remain under 120 mg/dl, the person can expect years of complication-free living.

In contrast, a person may wake with a normal FPG of 98 mg/dl (5.4 mmol/L) but end up spending the next 14 hours with blood sugars well over 170 mg/dl (9.4 mmol/L). That person is seriously at risk for heart disease, diabetic nerve damage, kidney damage, and retina damage.

So when you assess your own fasting blood sugar, the question you want to ask is this: How many hours a day am I spending with my blood sugar in the range that causes complications? Not, necessarily, how can I lower my fasting blood sugar?

Obviously, if your fasting blood sugar is over 140 mg/dl (7.7 mmol/L) and goes up after each meal, you are going to be spending many hours a day in the danger zone and lowering your fasting blood sugar does become a huge issue. Fortunately, it is also one that can be solved.


Several independent factors can raise fasting blood sugar, and if you have a problem with it, the reason for your problem may NOT be the same as the reason for another person's even if they get the identical blood test results that you get.

Here are common reasons for high fasting blood sugar.

1. High post meal blood sugars. Your beta cells can only make so much insulin. If you elevate your blood sugars severely by eating more carbohydrate than your body can handle, your body will spend the whole night using what insulin it can manufacture to mop up the glucose that is still circulating thanks to those high carb meals.

Many people with diabetes cannot handle more than 12-20 grams of carbohydrate at a single meal, no matter what you might have been told by doctors or dietitians. Many of us will find that if we drop our carbohydrate intake dramatically, our fasting blood sugar plummets equally dramatically. It may take as little as two weeks of restricted carbohydrate intake to see fasting blood sugars revert to normal.

You can use this technique to lower your fasting blood sugar. It has worked for literally thousands of people:

How to Get Your Blood Sugar Under Control

2. Damaged Basal Insulin Secretion. The body secretes insulin in two different physiological processes which are described on this page: How Blood Sugar Control Works--And How It Stops Working. I urge you to read this page because mastering the concepts it explains will greatly help you understand and manage your diabetes.

Basal insulin secretion takes place throughout the day without reference to what you eat. Tiny amounts of insulin are squirted into the blood stream in small pulses every few minutes. However, sometimes things go wrong with the factors that control basal secretion. If that happens, your body may still be able to secrete insulin in response to meal time rises in glucose, but you lose the ability to secrete those tiny pulsing bursts. This can cause a rise in fasting glucose that can not be corrected with dietary changes. If you have this problem, you might need a basal insulin--a slow acting insulin that mimics the effect of natural basal secretion.

Basal failure is relatively rare, but when it happens you often find people with high fasting blood sugars whose blood sugar normalizes as soon as they eat and stays normal until they have metabolized their last meal. There are also genetic forms of diabetes (GCK mutations) that will cause elevated fasting glucose, however, this will be a lifelong problem, not one that comes on with age.

3. Dawn Phenomenon. If your blood sugar is highest first thing in the morning, and normalizes after you eat or exercise and stays normal hours after dinner, you may have a disturbance of regulatory hormones that is called "dawn phenomenon."

Our bodies prepare for waking up by secreting stimulating hormones shortly before dawn. These increase our insulin resistance in order to raise blood sugar a small amount. If we were animals who had to go hunt for our first meal, that excess glucose would be useful. Since were are people with refrigerators, it is less so.

Everyone experiences this early morning hormone burst, but in people with diabetes it can become highly exaggerated. In some people it is resistant to any treatment, but once the person goes about their day and eats, the blood sugars become more controllable.

If you have dawn phenomenon that doesn't respond to various lowering techniques, don't panic. As long as you are spending most of the day with your blood sugars at a safe level (Always under 140 mg/dl and under 120 mg/dl as much as possible) you'll be fine.

4. Too Much Injected Insulin or Oral Insulin-Provoking Drug. This is counter-intuitive, but common. If you are using a basal insulin (Lantus or Levemir) there is a temptation to use a lot of it to try to lower post meal blood sugars. Your sugars will be pretty good as long as you keep eating carbs, but once you stop eating at night, the insulin keeps being absorbed into your blood stream and by 3 AM it is quite common to hypo.

However, many of us as soon as we hypo slightly, experience a burst of counterregulatory hormone intended to push the blood sugar back up to normal so by the time you wake your blood sugar is high, not low. You can tell if you have had a counterregulatory burst because it will often wake you up at 3 AM with a jolt. Your pulse will be fast and your blood pressure may be elevated too. If you measure your blood sugar it won't be low, because as soon as you get that jolt, your blood sugar will surge. That's what the jolt is meant to do.

If you are waking at 3 or 4 AM and end up with high fasting blood sugars, cutting back on your Lantus or Levemir may solve the problem. Lantus and Levemir are NOT meant to cover the carbohydrates you eat at meals, only to lower your baseline blood sugars. If you need insulin to control meals, you need to ask your doctor for fast acting insulin and the diabetes education it requires to learn how to use it correctly.

Glipizide and Amaryl (glimepiride) can also cause this problem as they cause long lasting insulin secretion in people who are sensitive to them.

5. Too Much Blood Pressure Medication. Too much blood pressure medication will also cause an early morning counterregulatory attack because if your blood pressure drops too low, you will get a burst of epinephrine and other hormones meant to keep you alive. It will raise both blood pressure and blood sugar.

I experienced this myself and since posting about it on my blog have received emails from others who experienced this same phenomenon. It is most likely if your blood pressure medication is giving you low normal readings during the day--90/60 for example, or if you experience postural hypotension attacks where you black out when you bend over.


Here are some of the things people report helped them. They are worth a try.

1. Cut way back on your meal-time carbohydrate intake.

2. Drink a glass of wine with dinner or before bedtime. One is enough. The alcohol can inhibit the liver from dumping glucose.

3. Eat a protein snack before bedtime.

4. Change the time of day when you take your medications. Metformin ER taken at bedtime will have a stronger impact on fasting blood sugar than the same pill taken in the morning. However, you may see higher post meal values if you change the timing. Remember your goal is maximum hours of lower blood sugar, not one low reading in the morning.

5. Split Lantus or Levemir doses so you take half in the morning and half in the evening. Lantus does not last 24 hours in many people, especially when taken in small doses (12-30 units) so if you take it in the morning it may be gone by 3 AM. Splitting the dose may give you better coverage. Discuss this with your doctor before you make changes, especially if you haven't been taught how to adjust your insulin doses. DO NOT MODIFY YOUR INSULIN DOSES IF YOU DON'T UNDERSTAND HOW THEY WERE SET!

6. Metformin. If you aren't taking metformin, ask your doctor about it. It is the most appropriate drug for controlling fasting blood sugars because it can sometimes block the liver dumping that raises blood sugar in response to dawn phenomenon hormones.


Unknown said...

Doesn't Byetta also lower fasting blood sugar by inhibiting glucagon?

michael plunkett said...

I no longer have a dawn phenomenon since doing some IF and eating most of my meals at night 5-8p. I wake up with my lowest numbers even after a night with later 'social eating or drinking.' My highest numbers are always in the afternoon before 4p regardless of meal plan, I can have an egg breakfast or a salad with protein lunch or no meals at all and the numbers are in the high 140+s. Even with the recent Riomet in the morning they hang in the 12-30's. I can't image having to manage several patients in BG number comtrol.

C said...

Just to say thank you very much for the post, much appreciated, particularly the discussion of the dawn phenomenon and suitable post-meal blood sugars.

(I also really appreciate you putting the mmol/l in brackets - I have had to write all over my copy of your book and I hate writing in books!)

Unknown said...

Thank you so much for the informative post. I have had a fbg of about 110 for about 20 years. My endo suggested (through the process of elimination of other diagnoses) that I had Mature Onset of Diabetes of the Young Type 2. This where the beta cells have a thermostat problem. Apparently my beta cells don't send out insulin until my bg is about 110 or so. After 2 years on a very low carb diet, my typical 1-hr pp is in the low 90s and my fbg is less than 100. My white bagel test elicited a bg of 143 at one hour.

Thanks to this site and I am relieved that the high fbg is less of an issue than post meal numbers -- I can control the after meal spikes.

Is there anyone else out there with this very rare form of diabetes?

Jenny said...

Regina, I have heard from several people diagnosed with MODY-2 (the GCK version that raises fbg) via gene tests. Cutting carbs does NOT lower their fasting blood sugar though they are advised to cut carbs to keep post-meal numbers low.

There are probably other genetic conditions that could raise the fasting blood sugar.

Stargazey said...

Thanks for this post, Jenny. I don't have diabetes, but these questions often come up, and it's good to have some practical answers to explain what might be happening.

lightcan said...

Hi Jenny,

Thanks for a very informative post. My mother has diabetes and she has had very poor BG control in the last 5 years or so from what I can see (she lives abroad). A few years ago, when she was here in my house, she was hypoing at night as you say, or after a walk. Before, at home, she would hypo if she didn't eat in time (even if her meal was 10 minutes late) or if she got anxious/worried/agitated I suppose higher cortisol lowers BG? There was definitely something wrong with her insulin dosage. She was in the hospital for observation since, but they have increased her carbs to 200 instead of reducing her insulin!

BTW, what do you think about blurry vision and blood sugar? Sometimes I see stars on the periphery of my vision. Once it was 2 hours after a low carb breakfast (sausages and eggs) and today it was at around 10 am on empty stomach. Could it mean that gluconeogenesis doesn't work properly? I suppose the liver is supposed to offer its reserves of glycogen in the morning anyway. I had half of glass of red wine with dinner yesterday. Could that be why?
Hyperlipid Peter suggested I keep my carbs spread out during the day. Maybe I should get a glucometer just to see what happens. But does low sugar in the blood reflect low sugar in certain tissues? As we know with low carb there might be insulin resistance in certain tissues, maybe muscles?
I ask because my mother has lost her sight almost completely due to retinopathy and there might be some retina weakness in my case too.

Jenny said...

Are you testing low--50 mg/dl or less-- when you see stars? If not, it is probably something else and you should discuss it with an eye doctor.

Diabetic retinopathy has NO symptoms until there is a bleed then there are dark blobs in the visual field.

Light flashes may be caused by age-related shrinking of the vitreous humor which can cause traction on the retina and has nothing at all to do with diabetes. It is common among people who are nearsighted, and worsened by abnormalities in the shape of the eye.

Eye strain can cause flashes too, again not related to diabetes. Get your eyes looked at by an optometrist or ophthalmologist if the problem recurs.

Unknown said...

I woke up one morning with bleeds in both eyes. The retinologist told me it had nothing at all to do with diabetes and it was all caused by my extreme nearsightedness. He did laser retinopexy in both eyes and said I had a lot of scarring around the edges of my retinas.

Mavis said...

Hi Jenny,

After one week (only) of low-carb, my fasting blood sugars are indeed the ones that are still most problematic. Why is it that high FBG is not as dangerous as post-meal high glucose?

I'm having trouble with the low-carb diet. It's triggering very bad insomnia. I also have dark circles under my eyes, I think from the strain on my adrenals. I upped my carbs *slightly* this evening. Okay before jog and at dinner, but when I was struggling to fall asleep, I ate an additional 10g carbs after my before-bed snack (about 10 carbs) and my BG shot up to 164. I did some exercises and brought it down to the teens.

I don't know how I'll ever sleep on such a low-carb diet, and that messes with my blood sugar, too. Plus, it's no way to live. I'd love to stick with it long enough to see results in my morning sugars (if that's a possibility for me), and my habit of a soothing night-time snack with carbs is definitely out. Any suggestions?

Mavis said...

And Regina,

I think I may have what you have, but I'm newly diagnosed with diabetes and have yet to see an endo. My patterns fit the profile.

Jenny said...


If you are eating a very low carb diet, it is normal to feel jittery at night at times for the first few weeks. It passes.

Circles under your eyes may be from dehydration. Cutting carbs shouldn't mess up your adrenals, in fact, it is what people are often told to do when taking cortisone drugs.

What you do is entirely up to you, but before you give up, I'd urge you to visit one of the diabetes discussion forums and talk to other people about your issues. They may have some ideas for you that are helpful.

We all have different things wrong with us, and if you can't lower your blood sugar with a diet, you will need to see a good endocrinologist to figure out what is going on and what the appropriate treatment would be.

Mavis said...

Hi Jenny,

I have become a member of dlife a few days ago and have made my first post on their forum - awaiting approval. I'm sure I'll be there a lot.

Hey, could you just clarify the thing about the post-meal spikes being more damaging than the nocturnal/dawn spikes? Why is that?

I don't mean I'm giving up on low-carb. It's effective in keeping my post-meal sugars in the safe range, though I'd like to keep them closer to the ideal range. (Thank you for pushing me in this direction!) But my sleep patterns have always been sensitive to what I eat, and if I undereat, or undereat anything my body seems to think is essential (it can be protein, fats, or carbs), I have a lot of trouble falling and staying asleep. It's like I'm on permanent overdrive.

I was discouraged by some posters on low-carb message boards who said the insomnia didn't go away over time for them. I do want to stick it out, but right now it feels like a vicious cycle, since lack of sleep and stress are surely messing up my blood sugar, too. I ordered a sleep tape and am seeing the doctor about temporary sleep meds. But this has been a lifelong issue for me and will always probably be my Achilles heel. (Now I'm wondering if Achilles had diabetes - that tendon!)

Right now I'm not sure if I'm hoping more for LADA or MODY 2 as a diagnosis. Sounds like MODY 2 would be easier to live with, but it would also mean that there's a 75% chance that at least one of my kids will have it.

I read your write-up about it and was concerned about the severe kind of diabetes that children who have MODY genes from both sides can develop. Is this the rare kind that shows up by six months of age? It's probably too soon to be speculating - I'm probably at least a couple of months from a diagnosis (endocrinologists are very booked up around here - have an appointment in August), but my husband has several male relatives that had severe, sometimes fatal, heart attacks in their 50's on his mother's side, and his father was diagnosed with Type II diabetes last year. He was overweight, but not obese. ...Well, by the time he was diagnosed, he was gaunt.

Jenny said...

Helen, Any spike over 140 mg/dl that lasts longer than a brief time does damage. A fasting blood sugar in the abnormal range between 100-130 is still a lot lower than those post meal spikes that do damage. A 2 hour 140 mg/dl usually implies a 1 hour value that is close to or over 200 mg/dl. It is those very high sugars that we worry about.

Don't "hope" for a LADA diagnosis as it means you'll end up insulin dependent. LADA is basically Type 1 diabetes. It is very challenging to manage.

With MODY-2 your fasting blood sugar would have been noticeably high all your life.

Don't make yourself crazy. Explore what you can eat and what works for you. Try different things. You'll find foods that work better than others by experimenting and testing. If you find food doesn't make a difference, that's useful information too. Keep track of what you learn and wait until you see your doctor before panicking.

The main thing to keep in mind is that it is ALL manageable.

Unknown said...

For what its worth...when my endo diagnosed me with MODY-2 almost 2 years ago my A1C was 5.5. I had been on a low carb diet for about 2 months. He said that 5.5 isn't great, but people with MODY-2 don't typically develop cardiovascular disease with an A1c of 5.5. I hope my A1c is lower now after 2 years on a low carb diet. I see a new endo in Sept -- the wait is over 6 months.

I typically don't have trouble sleeping since starting on the low carb diet -- I only have trouble if I don't eat enough dinner and go to bed really hungry.

Mavis said...

Okay, I've read a little more and am more confused. Yes, I agree, I'd rather have MODY than LADA.

I have had elevated fasting glucose all my life, over 100, but under 107. (I don't think I've been aware of every test, so I'm not sure how consistent this is, but it's been consistent in the tests results I've seen.)


*Does MODY 2 deteriorate over time? My FBG is much worse now. It was 143 at about 4:30am today.

*Does glucose tolerance deteriorate as well? Mine certainly has.

*If so, what causes the deterioration?

*On the other hand, with LADA, would I have seen the elevated FBG all along? Would I have had somewhat impaired glucose tolerance in the past (good A1C, perhaps because of good diet, but slightly off OGTT results many years ago)?

Jenny said...

If you have had abnormal fasting blood sugar all your life MODY-2 is a possiblity and you should ask your doctor to test for it.

MODY-2 doesn't have to deteriorate, but many of us, self-included, see our blood sugar get worse as we get older. Certain drugs can worsen it too. Prednisone or SSRIs for example.

LADA usually develops quickly with no previous symptoms--within 5 years most people with LADA progress to insulin dependence.It often occurs with other autoimmune conditions.

Unknown said...

Dr Eades told someone they could have an herbal tea at bedtime with one teaspoon of sugar and it would lighten the ketosis enough to let them fall asleep. I can't remember if the commenter was diabetic or not but they were having trouble falling asleep because of the extra energy from ketosis.

Unknown said...

For help falling asleep try taking some magnesium before bed. I take 425mg of magnesium citrate every night and sleep like a baby even with a VLC diet. Good call on the BP medicine. My fasting BG has been about 15-20 points higher than normal for a few days. Last night I didn't take the BP meds and woke up at 87.

Mavis said...

Hi Jenny,

To make a long story short, I am almost positive I have MODY 2. I've been reading the literature I can find about it and the shoe fits remarkably well.

I've been doing a 60-carb/day diet for two weeks. To my dismay, I can usually catch my sugars nearing or exceeding 160 no matter how few carbs I eat. (I think this must be due to my liver dumping out glucose during the meal, something that MODY 2s do.) Sometimes it happens earlier than one hour pp, and can be back as low as 95 one hour pp. Sometimes it's that high one hour pp, but goes below 120 two hours pp. Come to think of it, the curve might have to do with when I take my last bite, rather than my first.

My morning glucose hasn't budged. It's ranged from 118 (no idea why) to 145 (today). It used to be lower in younger days - not sure why it's higher now, but it was in MODY 2 range then, and it is now, just different ends of the scale.

The low-carb diet is helping me lose weight and I think it's increasing my insulin sensitivity and lowering my overall insulin burden. I think the reasons my numbers had gotten more out of whack lately were gaining 20 pounds since last summer (not sure how that happened - I've never been this heavy), age, stress, and sleep deprivation, though only the age and weight are new. But that could be enough, so I am on a fitness campaign. (I already exercised, but now it's with an eye to improving insulin sensitivity.)

I guess the good news in this is that MODY 2 doesn't usually lead to complications. MODY 2 types tend to have low triglycerides, which I've always had, in keeping with the pattern. So if one is to have diabetes, MODY 2 isn't the worst way to go.

My question to you - seeing as it's a glucose "set point" problem - is it still worth it to go low-carb? Could it even be counterproductive, seeing as MODY 2s don't synthesize glycogen as well as they should? Could this be why I feel tired and skittery on this diet? (As in, it's much harder to sleep, a problem I don't need, exercise comes harder, and my pulse feels slippery.)

I don't think I should go to high carb, but do you think adding carbs back it might be safe and even possibly helpful, given my (probable) type? I figure you'll say "try it out," but I hate the thought of seeing higher numbers. I suppose if I see them, then the answer is no.

Jenny said...


Mainstream doctors recommend that people with MODY-2 cut carbs. It won't change the set point but it will prevent the blood sugar spikes after eating. Preventing the spikes goes a long way towards preventing complications.

There is a test available for MODY-2. Get tested before concluding that is what is going on because treatment would be different if that was NOT your diagnosis.

Mavis said...

Hi Jenny,

I'm going to try to get tested as soon as possible. If my new PCP is willing, that will be soon. If not, I see an endocrinologist in August. I realize that treatment would be very different with a LADA or a different MODY.

Thanks for all you do.

BTW, fasting glucose was 89 today. That is good, but not suggestive of MODY 2, so I'm not sure how to feel about it!

Unknown said...

Helen, Another strangle phenomenon I have noticed with MODY-2 is that my blood sugar tends to go up the longer I wait between meals. I am still testing this, but yesterday my BG was 96 1- hr pp and it rose all afternoon until it was 118 6 hours later. I ate nothing during the 6 hours. I wonder if I should eat a snack in the afternoon, and I understand too frequent eating can causing "stacking" or even higher blood sugars. I will continue to test to see how I can keep my BG the lowest.

Mavis said...

Regina - That happens to me, too, although... not always. I feel like my blood sugar keeps creeping up without a glucose load large enough for my pancreas to "get the message." I wonder if on that one low day, my overnight blood sugar had actually been higher than usual at some point, starting the drive back down. I'd had a larger snack.

I think possibly being MODY 2 is why I've never been able to successfully fast or even "go raw" for a cleanse. And why a vegan diet makes me want to die. (I don't mind the food, just how it makes me feel.) And why I've always noticed that sugar messes me up but good. And that "grazing" makes me feel like I haven't eaten anything at all, even it it adds up to a lot of food. Does any of that sound familiar to you?

Unknown said...

Helen - I have a hard time fasting as well. I really think the longer I wait to eat, the worse my BG numbers are. I am going to experiment with timing of meals. Lately I have a problem with eating a meal, feeling very full and then getting hungry one hour later. I can't decide if I am not eating enough, or if there is something weird happening.

There are times my pancreas just doesn't get the message. I had several weeks of fasting numbers in the 90s and then boom 131 -- I am mystified by all this. I sometimes wonder if a few carbs are helpful. I usually keep under 30-45 per day, but even if I eat a a little ice cream my 1-hr PP is usually under 110. Once my pancreas wakes up, all works great. I guess that is the MODY-2 SOP.

Debbie Young said...

Hi Jenny,
I love your blog, it is helping me not freak out since I have found that my fbg ranges from a low of 106 to a high of 125. Most days it is around 115. Yet, post meal (mixed protein and some carbs) it seems normal. 125 at one hour, 120 at two hours, 114 at three hours.
My father and his sister were type one diabetics, not very well controlled even with daily insulin injections. So the 'D' word scares me quite a bit.
What protein snack is best? I tried doing almond butter, a little honey and some cinnamon and got a 114 fbg the next am. Perhaps some cheese would work better? I will try it tonight.
Thanks for all you do,
PS I also have CLL, chronic lymphocytic leukemia, stage zero. I am wondering if my liver function (which tests normal by onc.) is affecting my fbg numbers too. What do you think of taking Milk thistle?

theSandpiper said...

I woke up this morning with a fasting blood glucose of 132. worked on computer. no coffee, no nothing, except my own saliva.
2 hours later I take my sugar count again before breakfast and it's up to 144. Why ? I need to ask. my vision is not all that good, and I may have missed the answer in the posts. thank you.

Jenny said...


When many people with diabetes don't eat, their livers release glucose inappropriately. Livers are supposed to release some glucose to keep blood sugar from dropping too low, but some people secrete too much of the hormone glucagon which stimulates the release of glucose in that situation. Be sure to eat some breakfast (ideally one very low in carbohydrate) as soon as you wake up.

shuvra verma said...

I am diabetic n on medication. My post perendial test show normal results but fasting bld sugar is always hi between120 to150mg how to control suggest

Jenny said...


The best treatment for what you describe is to add a daily shot of long-acting insulin to your regimen. You might discuss this with your doctor. Many doctors hold off prescribing insulin under the belief that patients are too frightened to do it. This is a shame. With today's ultra thin needles the shots are painless, and the insulin is very effective in lowering fasting blood sugar.

Unknown said...

My FBG are always in the 6 to 6.8 range. My Post-Meals after 2 hours always are low and in the 3.4 to 5.5 range.

Is that Ok? On Metformin and Diamicron and Low Carb.

Jenny said...


Those readings at 2 hours are too low. Diamicron causes insulin to be secreted without reference to how much glucose is in the bloodstream. When you lower your carb intake, you need to lower or eliminate your dose of Diamicron. Otherwise, you can experience dangerous hypos. You don't ever want your blood sugar dropping below 4.4 when you are taking Diamicron, because if it keeps going you can get into the range where you become unconscious.

Talk to your doctor about the lows you are seeing and what dose of diamicron would be appropriate. 3.4 is considered a dangerous reading.

Unknown said...

hi jenny....your post is very useful. for dthe first time i had fbg 130 mg and after meal it is 89 mg. before this result i had fbg 70-80mg. im worried and want to know if i need any medication? thanks

Jenny said...


A single high reading may be due to meter error or having something on your finger. Only if you continue to see many high readings, you would need to act. Your other readings sound very normal.

If you see many high readings, first try the strategy you'll find at this page How to Lower Your Blood Sugar. Then if that isn't enough, talk to your doctor.

Unknown said...

Hi Jenny,
After my annual medical examination this year my HA1C was 6.O & Fasting sugar level of 5.6. I have no previous history of blood sugar problem and using no medication. Almost 3 month before this test I joined Gym and was on high protein & high crab diet(High carb & protein meal with 4 cups of coffee with sugar, fruits and sweeteners in between.). My doctor total me everything is absolutely fine and there is nothing to be worried about, but as a caution I started monitoring my blood glucose level using One touch altar 2. My post meal numbers are always in the normal range, After 2 hr anywhere from 5.3 to 6.6, rarely close to 7. But my morning Blood sugar is usually in the pre-diabetic range 5.9 to 6.3 using home meter. My Fasting glucose level other then morning stays in the normal range of 4.8 to 5.5

Please see below 2 Hours readings after normal diet 1.5 bread (pita) with meat or veggie. some time take sweet after meal (just to check results)

5.3-5.5 (sees some time)
5.6-6.6 (Mostly)
6.7-7.0 (Rarely)

Fasting blood glucose level in Morning

5.5-5.8 Rarely
5.9-6.3 Mostly
6.4 -xx Never

Fasting Blood Glucose level Day time. (Other than morning)

4.6-4.9 sees some time
5.0-5.5 Mostly
5.6-5.7 rarely

I am in late 20s Turing 30 this year. I am concerned about my FBGL if it’s an issue or it’s normal in few non diabatic to have little higher numbers in morning? My parents are diabetic. Father can handle sugar level without medication (age 70) & mother insulin dependent (Age 60). If this is a really threat what precaution i should take to avoid it and how much time it can take to develop to full blown diabatics. Or its is totally preventable or not.


Jenny said...


When both parents are diabetic, there is a strong genetic component involved, and despite what you have heard, those genetic components are a major cause of diabetes. So yes, you have a greater chance of becoming diabetic than someone without diabetic parents, and that higher than normal fasting blood sugar does tell you that you are not making insulin in a totally normal way.

The good news is that you can do a lot to prevent progression no matter what your genes. Start cutting back on the carbs you eat at meals. Even if post meal numbers are normal, it's likely your pancreas is struggling to make the insulin to cover those meals and doesn't have the capacity left to store insulin for the fasting state. Less carbs at meals lets you accumulate more insulin for fasting.

If your blood sugar continues to rise despite cutting carbs, then it is possible you have an autoimmune component at work, too. but at this point I would not leap to the conclusion that is what is happening. Perhaps you have inherited a "thrifty gene" which simply can't cope with the abundance of food now available to you.

Unknown said...

Thanks Jenny for sharing your valuable knowledge with all of us. You are doing a wonderful job.


Unknown said...


I have been wheat free/sugar free, low carb (no more than 25 a day), and my blood sugars still run slightly on the high side (90-100). This doesn’t really bother me much, because the levels remain consistent mostly even during the day, with very minimal fluctuation even after eating. I have not, nor ever have, been diagnosed with diabetes. I am on NO medications, with the exception of vitamins/supplements (magnesium, potassium, etc)

However, my concern is regarding the fasting blood sugars. Now, I don’t sleep well at night (I have a 9 year old son and take care of elderly parents), usually only getting about 5 hours max. When I wake at 3am, my blood sugar is 106 or so. I will read a book or such until 5:30 when I wake for the day, not eating but just drinking water, to find my blood sugar has increased to 125. I am hungry at this time as well. Two hours later, after showering and preparing things for the day, I’ll make/eat breakfast, where my pre-breakfast blood sugar is 130. A half hour after eating, my blood sugar is down to 119, and continues to go down throughout the day, leveling off around 95-100, again with very minimal fluctuations.

I do drink coffee during the day, with heavy cream and some stevia, which doesn’t raise my sugars, but due to the lack of sleep, this consumption has increased. I switch to decaf after noon, however. Previously, I thought that the rise in blood sugar was the Dawn Phenomena, and had a small snack before I went to bed. I found that my nightly blood sugar (at 2-3am) was 125, and my pre-breakfast blood sugar was 150. I now do not eat after 7pm. I do not exercise outright, though I do take the stairs at work and often play with my son.

So, I’m confused as to what would cause the blood sugar to rise while awake without eating, and then lower after eating (though I can understand this based on the LCHF diet I eat). I’m sure this is a hormonal response, probably cortisol. I’m thinking it’s related to my lifestyle, and lack of sleep (pretty obvious, I think). Would the morning increase in caffeine play a role in this as well?

Is there any other physical mechanism that might cause blood sugar to rise without eating?

Thank you! LeeAnn

Jenny said...


Lack of sleep is known to raise insulin resistance. But whatever the explanation, if you are getting fasting blood sugars over 125 while eating a very low carb diet, you need to talk to your doctor. Those are very high readings for someone on a VLC diet and they are high enough to give you a diagnosis of diabetes even eating a non-LC diet.

It is possible that Metformin might help bring down those fasting blood sugars, as it is good at doing that when dietary change doesn't get it done.

Even though your daytime numbers are still normal, the concern I would have is that over time, people who first develop diabetes with a pattern of high fasting numbers alone usually progress to having high post-meal numbers, too.

So you don't want to ignore this. For most people the advice would be to cut carbs, but since you are already doing this but still seeing those high fasting numbers the next step would be to use metformin to counteract the insulin resistance.

Don't let the doctor talk you into any of the other drugs, however, as no other drug reduces insulin resistance the way metformin does without disturbing, dangerous side effects.

Unknown said...

God bless you for posting this! I am a "beginner" on the diabetic scene; very bad for me because, although I am an eater I have been a low carb and NO SUGAR and very little salt for a long time and I have high B.P. and now... diabetes. I was desperate with my early morning fasting levels! This article put me at ease with some suggestions and the "dawn syndrome" explanation. I feel better now. I printed this article and the recommended ones and will be showing it to my doctors!
Thanks, Milt

Anonymous said...

my blood sugar always drops around 5:30 can be anywhere from 90-40 depending on how tired I am and slow to get up...I wake with the shakes and soaked from sweat...I am taking humulin r 500 and take 13/15 units twice a blood sugar before bed averages 200 - 350 and by noon I am usually around 200...why does it drop at the same time each morning and what can I do to prevent this

Jenny said...

Ann Marie,

Your insulin regimen is unusual. R500 twice a day is not a common prescription. I assume you are seeing an endocrinologist. If so, you need to contact him or her and discuss how you can avoid those lows and lower those highs.

If you were not given this regimen by an endocrinologist, you need to see one ASAP and get help adjusting your doses so that they are more effective and safer.

Anonymous said...

I see the Top Endo in my State...What is so unusual about script says take twice a day...Doc said with breakfast and then dinner...I fast from 12-12...I usually eat about 2 and 10...5:30 / 6:00 would be midrange...I was simply trying to understand why I crash at that time - while I am sleeping...I do not decide my own medications...if it were up to me I would not take anything at all...this is the third medication he has had me on as I am insulin resistant...I am simply looking for a tip I guess...a suggested food product or beverage for prior to bed perhaps

Jenny said...

Ann Marie,

As I said, you are using an unusual insulin regimen, and if you were given it by an endo, they must have their reasons for prescribing it. So you need to talk to the endo about the problem you are having with the lows and find out what they want you to do. They may need to adjust your dose, but they won't know that if you don't tell them. Getting insulin to work properly takes some adjusting.

Karen said...

I have been pre-diabetic for over 10 years and have controlled by diet and exercise. Lately due to stress and depression i have seen a steady increase in BGL. My A1c was 7.7 when i visited my doctor one month ago. She advise that I start Metformin. I declined and expressed that i would like to start a very strict regimen of tight diet and exercise to attempt to bring this down. I have since lost 15 lbs and my BGL has been lowering. However i ahve had some weird things happen which may relate to stress? Four hours after my lunch today I checked and my level was 6.2 then i went outside and did some light chores came back in an hour later and checked again it was 7.2! I was surprised to see this after i had exercised and not eating a snack. What causes this and how can i manage it? I am committed to adhering to a strict diet of no white flour, no white pasta and no white rice. I have given up alcohol comepletely, and diet pop. My wieght is dropping so I am hoping that I can keep on managing this without medication. Is this doable? Karen

Jenny said...


Stress rarely raises blood sugar unless it is the kind that results in a pounding pulse. There is a certain amount of variation in strips that could account for some of the rise--if you see an unexpected reading it is a good idea to wash your hands and then test again, but I would hesitate to blame this rise on stress.

I'd suggest that you learn more about how much carbohydrate there is in the foods you eat. Blood sugar rises in response to all the carbohydrates you eat, so while cutting out the white stuff will remove a lot of carbohydrate from your diet, there are many other foods with a lot of carbohydrate in them that you may still be eating.

It is possible that you digest some foods slowly, and that could explain the late rise. Pasta will do this whether white or whole grain.

Download some nutritional software for your smartphone or tablet, or get a book that lists the nutritional value of foods to see how many grams of carb there is in the foods you enjoy eating.

It also sounds like you are operating under the common, but mistaken, belief that it is somehow healthier to control entirely through diet rather than taking metformin. While most of the diabetes oral drugs are dangerous, metformin is generally believed to be safe and has the very important effect of lowering your insulin resistance, which means your body makes much less insulin to cover the same amount of food. Using it in combination with a lowered carb diet may be very helpful if you have the traditional form of Type 2 which involves insulin resistance. It is also very helpful with weight loss.

Adopting a very strict diet may work, but the problem is that far too many people can't stick with that diet for the next 30-50 years, which is what you will have to do, since diet will not change the underlying condition, just control the blood sugars and avoid complications.

So the best goal is to find a diet that you can stick with without burn out. If metformin makes it possible to do this, there's no reason not to.

tigervirk said...

last year after retirement I fell to the attack of unexplained anxiety. My sleeps were out. Could not sleep for days even with sleep tablets.Thanks to my Doctor daughter who took me to the Psy Doc. I was administered Lonazep followed by combo of of Nexito and Bupron in increasing order.what surprises is that my morning fasting level continues to be 106 and PP 94 and 103. I remained worried all the times. Thanks to your blog that I have opened today; that I can have a comfortable night;realising that there are so many of us with similar problem for so many diverse reasons. I am going to follow your advice on cutting down on my carb during night. I come from gym around 8PM and would have taken a shot of protein supplement in normal water after my work outs.Will his plan work?Thanks a to for the knowledge sharing

Jenny said...

The only way to know if your plan will work is to try it for a few weeks. We are have different underlying problems causing our elevated blood sugars, so different strategies will work for different people,

Give it a try, and if it doesn't work try something else.

rishikesh chidhambaranathan said...

Thanks for the blog. I am recently found out type 2 diabetic. My hbc 7.5 and prescribed metformin bid. But after taking a week I stopped and started using complete diet control. But still, my fasting bg is 130 and above. I eat fruits and rotis which is less of carb. But still I cant understand why fasting bg is not less than 100. Pls advice. I eat 1 apple morning and 2 rotis afternoon with salad and for dinner 3 rotis with salad. Using b complex for my leg buried sensation.

Jenny said...


You may not be making enough insulin to covrr the amount of carbs you are eating. Take the metformin with your new diet and see if that helps. It often loiwers fasting blood sugars.

Also, you need to be eating more protein, too.

Unknown said...

I don't believe that low carb diets are good for NIDDM
diabetics, since the alternatives are fat and protein.
High protein diets can lead to raised basal IGF-1 which is a driver of type II diabetes, and high fat diets lead to adiposity which is also a driver of diabetes, especially saturated fat which increase inflamatory cytokines IL1 and TNFalpa, directly and indirectly via increased adipose tissues. A healthy approach is to lean towards a predominantly plant based diet with lots of complex carbohydrates and naturally high nutrient density. Diabetes is characterised by polyphagia, which to me indicates a malnutrient disorder. So a good diet is < 15% protein (5% from animal sources) in calories and 75% - 80% complex carbohydrates from plant sources, and only 5% - 10% fat.

Jenny said...

Michael, While you are free to believe whatever you want, the "facts" that you cite are not based on human research which shows that when people with abnormal blood sugar stick to low carb diets, they lose weight, improve lipids and other hormonal measures of health. The research you are relying on is mostly derived from rodent research conducted in rodents that were chosen as models of human diabetes because they become diabetic when fed high fat diets which are also full of fructose-laden corn syrup. Humans, on the other hand, become diabetic when they eat high carb diets

I hear from hundreds of people with diabetes each year and have for over a decade. I have yet to hear from anyone who has attained long-lasting remission from diabetic blood sugars by eating a high carb plant-based diet. I have heard from several who have tried such diets with very poor results.

Such a diet causes ravenous hunger and raises blood sugar. They are promoted by a celebrity doctor who is trained in psychiatry, not endocrinology, who has never actually treated patients with diabetes, and who is supported actively by PETA--hence the strong vegan flavor of the propaganda.

She said...

I could not agree more with your last comment, Jenny. For 3 years I followed a strict whole plant foods McDougall diet with the exact proportions Michael Mckeon recommends. At first all seemed well but it became an utter health disaster with extreme polyphagia and out of control blood sugars. I am now non-vegan and lower-carb and have reversed these trends, with outstanding bloodwork and likely the best health of my life.

What works for some does not work for all. Do not be blinded by vegan or any other hype. Jenny's work, along with others', set me straight.

She said...

I should add I did not have diabetes when I embarked on the high-carb lowfat diet. By the time I went off it, I was well down the road to full-blown diabetes. I feel very fortunate I caught this in time, and feel duped by the "prevent and reverse diabetes with a whole-foods plant-based diet" propaganda. What utter tripe that is.

Unknown said...

My sugar is always 150 to 170 in the morning when I wake. After I eat its usually around 130. My A1C is ok my doctor says what does that mean?

Jenny said...


That sounds like "Dawn Phenomenon" which is discussed on this web page: Why Is Blood Sugar Always Highest in the Morning?

Unknown said...

This is the most information I've gleaned in 18 years of being Diabetic ! Thank you ! x