What is a Normal Blood Sugar?

Over the past year I've been tracking the searches that bring people to this site and have found that the single most popular search that brings in visitors is "What is a normal blood sugar?"

Much of this web site is devoted to answering that question in great detail with references to dozens of laboratory studies published in top peer reviewed journals. If you want the details, you can find them on pages like Research Connecting Organ Damage with Blood Sugar Level.

But, if, like many people, you just want a quick and simple answer to "What is a normal blood sugar?" Here it is.

Truly Normal Blood Sugars

Fasting Blood Sugar

A normal fasting blood sugar (also the blood sugar you'd see before a meal) is roughly 83 mg/dl (4.6 mmol/L) or less. Many normal people have fasting blood sugars in the mid and high 70 mg/dl (3.9 mmol/L) range.

Post-Meal Blood Sugar (Postprandial)

A truly normal person eating the high carb typical American diet does not go over 120 mg/dl (6.6 mmol/L) one or two hours after a meal and many are under 100 mg/dl (5.5 mmol/L) two hours after eating.

A1c

A truly normal A1c is 4.6% or less. That is the level that corresponds to a blood sugar kept under 100 mg/dl (5.6 mmol/L) at all times. Heart attack risk starts to rise in a straight line fashion as soon as A1c goes over 4.6% and for each 1% of rise it is 2.3 times MORE frequent. That means that at a 5.7% A1c you have two and a third times more risk of a heart attack than a person has with an A1c of 4.6%.

A Continuous Glucose Monitor Study that Looks at Normal Values New!

Here's an illuminating research study that was presented at a major European conference in September, 2006. It reports on the daily pattern of blood sugars of a group of normal subjects as revealed by continuous blood sugar monitoring.

What is Normal Glucose? � Continuous Glucose Monitoring Data from Healthy Subjects. Professor J.S. Christiansen, presented at the Annual Meeting of the EASD.

The main findings here, for those of you who don't have the high speed internet connection needed to listen to this presentation, is that in normal people fasting blood glucose throughout the night stays flat in the low 80 mg/dl (4.4 mmol/L) range. After a high carb meal, blood sugar rises to about 125 mg/dl for a brief period, with the peak blood sugar being measured at 45 minutes after eating. The chart at the top of this page is taken from this presentation. Notice that in all but the people with the highest brood sugars in the group, blood sugar is under 100 mg/dl (5.5 mmol/L) at 1 hour and 15 minutes after eating and it returns to 85 mg/dl (4.7 mmol/L) by 1 hour and 45 minutes after eating.

Note also, how much lower even the highest of these normal readings are than the ADA's diagnostic cutoff for "impaired glucose tolerance" which is 140 mg/dl two hours after eating!

A few people in the study went as high as 160 mg/dl (8.9 mmol/L) after the high carb meal, which may be because they are not entirely normal. The study recruited normal subjects based on their A1c, and the highest A1c in the study was 5.4% which may, in fact, represent early deterioration of postprandial blood sugar control.

This study also documents that eating a high carb meal for breakfast results in an unacceptably high blood sugar swing much higher than any other blood sugar rise seen throughout the day, even for normal people, a point that the professor stresses in his presentation.

The study also makes clear that the same amount of carbohydrate eaten at a meal other than breakfast does not raise blood sugar anywhere near as high. The body seems exceptionally unable to process carbohydrates first thing in the morning. So throw out the Corn Flakes!

Why Does the Lab Sheet Give Much Higher "Normal" Values?

The reason that your doctor or lab might consider much higher numbers as "normal" is because for decades the ADA arbitrarily decreed that a fasting blood sugar level below 110 mg/dl was "normal", as was a 2-hour Glucose Tolerance Test value of 140 mg/dl (7.8 mmol/L). They also decreed that an A1c of 6% was "normal" though this level corresponds to an average blood sugar of 136 mg/dl.

These definitions were arbitrary, designed by a committee whose stated goal was to prevent patients from being diagnosed with the D-word because of it's "stigma". These arbitrary definitions were based on some very faulty logic. (details HERE).

The research on the Organ Damage Page will give you many more substantial reasons supporting the argument that the ADA's arbitrary definitions of "normal" are much too high.

If your reason for wanting normal blood sugars is to avoid all diabetic complications and the blood sugar swings that make for rotten energy, shoot for true normal. Not the "normal" that is high enough to damage your organs.

Why Does My Doctor Think High Levels are "Good Enough for A Diabetic?"

Because it takes work and study to bring blood sugar down to truly normal, truly healthy levels. If you only want to take a pill and do nothing else, the only blood sugar levels you can get to are the "good enough for a diabetic" levels that, as you can see elsewhere on this site, are "good enough" only if you think neuropathy, retinopathy and a heart attack are "good enough."

Though your doctor may think you are too lazy to do the work needed to get normal and not explain to you what it takes to achieve normal numbers, people with diabetes CAN and DO attain these normal blood sugar numbers and you can, too.

What It Takes to Get Normal Blood Sugars

Education

You must learn how many grams of carb there are in every thing you eat, which includes weighing portions until you know what the "portion" listed in a Nutritional Information listing really looks like. Hint: It's MUCH smaller than you think. You need to learn in detail about what various drugs can and cannot do, and if you use insulin you must spend a lot of time reading about how to make it work. Bulletin boards and newsgroups are a good place to find people who have done this. Only take advice about how to get control from people with diabetes who have normal and near-normal blood sugars.

Cutting carbs

Carbs are what raise your blood sugar. Unless you are using insulin and are a genius at making it work, you are not going to be able to eat 100 grams of carbs a meal and control blood sugar. Somewhere between 12 and 30 grams a meal is the level most people with diabetes eat who maintain normal blood sugars.

Exercise

Some people find this helps greatly with blood sugar control. Others find it has no impact. It has a lot to do with what has made you diabetic. If it is mostly insulin resistance, exercise can usually help a lot. If it is insulin insufficiency, exercise is beneficial but won't necessarily normalize blood sugars on its own.

Meds

If you can't get to normal blood sugar levels with carb restriction and exercise alone, it's time to check out drugs that lower insulin resistance, most notably Metformin. Byetta is another drug some people are finding very helpful in attaining normal numbers.

Insulin

If diet and metformin don't do it, use insulin. When most doctors prescribe "insulin" to a person with Type 2 diabetes, they prescribe a long lasting "basal" insulin like Lantus. However, a post-meal or basal insulin like Novolog works a LOT better for many of us than just Lantus, because Lantus can't bring down meal values to normal levels for most people.

If you stress your beta cells at every meal, you are going to end up with non-normal blood sugars. So a basal insulin dose may not be enough to do the job. Most doctors won't suggest that you use a meal-time insulin, because it takes a lot more work and study, but for many of us, using very small meal-time insulin doses is the only way we are going to see normal blood sugar levels.

It takes a lot of work and study to get insulin to where it gives you normal numbers. Most doctors can't be bothered and settle for numbers that won't keep you from developing complications. Read the excellent book, "Dr. Bernstein's Diabetes Solution" by Dr. Richard K. Bernstein to learn more about how to tailor insulin regimens so that they give you normal blood sugars.

That's it in a nutshell.