Everything You Need To Know About Blood Sugar
Estimated reading time: 6 minutes
Diabetes is all about blood sugar, and if you're going to manage this serious condition effectively, knowing everything about blood sugar is a good place to start.
No doubt you know that diabetes has something to do with “blood sugar” or, more correctly, blood glucose. I mean, we talk about it all the time. But do you really understand why there’s sugar in your blood in the first place, how it got there, how much there should or shouldn’t be, and why all of a sudden you’re responsible for this? OK... Pull up your pants legs, and let’s wade in. This is fundamental knowledge we all need to understand as we face diabetes.
Table of contents
Let's Talk Chemistry
Now... Here’s the perfect line to lose an audience, but don’t go… This is 20 seconds… Ready. Let’s talk chemistry. “…I’ll give you a second to recover. OK, understand that “sugar” is both a common term…like for table sugar…and a chemistry term. When we say “blood sugar,” we mean the specific chemical sugar glucose. Diabetes is all about glucose. There lots of sugars….table sugar is sucrose, malt sugar is maltose, milk sugar is lactose, and you’ve probably heard of fructose. It’s ok to say “blood sugar” because we all know what that means…..but it’s really blood glucose because that is the specific sugar that circulates in our blood.
It's Our Fuel
So, why does glucose circulate in our blood anyway? Because it’s our fuel. All of our billions of functional cells, like muscle cells and especially brain cells, grab the glucose that’s passing by in our blood and “burn” it for energy. Glucose is your preferred fuel, and our blood is the delivery truck. Many cells, like muscle cells, take in some extra glucose and store it for later. Your brain alone accounts for an estimated 20% of your daily energy, and according to my husband, Tony, sometimes his brain is doing absolutely nothing. Your body can get energy from other sources, but glucose is preferred.
Where does this glucose come from – food, specifically carbohydrate-containing food. All sugars are carbohydrates….but so are starches and fiber. Starch and fiber are made from many sugars bound together, including lots of glucose….the difference between sugar and fiber is like the difference between a single brick and a brick house made from thousands of bricks….starch is in between, more like the proverbial brick “outhouse.” When you eat these foods, all the glucose “bricks” that are freed from indigestion go straight into your bloodstream, adding more glucose to your blood. Got that - the glucose from the carbohydrate food you eat goes straight into your blood.
Be Sure To Check Out - Understanding Diabetes
The Blood Glucose 'Goldilocks'
Now it happens that there’s a “goldilocks” just right amount of glucose we want circulating around in our bloodstream. On your blood glucose meter that reading would be something like 85 or 4.7 depending upon where you live. That’s just two different ways to measure blood glucose - 85 milligrams per deciliter in the U.S. and other places or 4.7 millimoles per liter in Canada and other counties. Don’t get hung up on the math….our goldilocks blood glucose level means you have approximately 4 grams of glucose circulating in your blood. That’s 4 grams….between one and two-tenths of an ounce!! That’s approximately equal to the carbohydrate from 2 club crackers, or one-quarter of a small apple, or 1 teaspoon maple syrup.
So you may ask….if people only have 4 grams of glucose circulating in their blood for a perfect reading of 85 and every gram of glucose they eat goes straight into their bloodstream what happens when they eat…when we eat…. Say 40 grams of carbohydrate….like half a large baked potato…..10 times 4 grams. Wouldn’t that make the blood glucose level 850 instead of 85? YES- Now you have it- that would make blood glucose 850 mg/dl or 47 millimoles/liter, except your body has that worked out perfectly… Unless we have diabetes. I’ll explain.
Ordinarily, as soon as that digested potato sends blood glucose levels rising your body releases insulin. Insulin rounds up the excess blood glucose and begins escorting it into those cells that can store it for energy or to special storage space in your liver. Blood glucose will definitely rise, maybe to 180, but insulin is working away. Normally, blood glucose will be 140 or below 2 hours after eating and continue returning to a normal range below 100. With diabetes (or prediabetes) this doesn’t happen efficiently. So what is happening? What’s different with diabetes?
Type 1? Type 2?
Well, either there is
- essentially no insulin being produced - that’s type 1 diabetes…
- or some cells are refusing insulin’s influence and are not taking in glucose for storage, leaving that sugar circulating in the blood. That’s called insulin resistance, and that’s what defines prediabetes and type 2 diabetes.
It’s also possible to have both things going at once.
- People with type 1 diabetes can develop resistance to the insulin we have to inject.
- People with type 2 diabetes can experience a reduction of insulin-producing capacity.
The bottom line, and what actually defines diabetes, is that blood glucose levels go higher after eating and stay higher after meals for longer than “normal.”
Let's Talk Numbers
Alright… Let’s talk numbers. First, understand that my use of the word normal isn’t about you or me - it’s about blood glucose levels in the same way that 98.6 is a “normal” body temperature. OK? So, a normal “fasting” blood glucose level, no food in the previous 8 hours, is between 70 mg/dl and 99 mg/dl. Divide milligrams per deciliter by 18 to get millimoles per liter. If fasting blood glucose is 100-125, that is considered prediabetes or “impaired glucose tolerance,” and 126 or higher after fasting is considered diabetes. Diabetes can also be diagnosed by a “glucose tolerance test,” which actually monitors the rate fasting blood glucose rises and comes down after consuming a specific carbohydrate drink, usually 75 grams of carbohydrate. In that test, blood glucose levels above 200 mg/dl, two hours after consuming that drink, is diagnostic for diabetes.
Be Sure To Check Out - Intermittent Fasting for Diabetes?
Blood Glucose Goals
Ok, now that we have diabetes, what are our blood glucose goals? We know that high blood glucose levels are damaging and, over time, can lead to serious health issues.
This is really important: managing our average blood glucose levels can greatly reduce those health risks even if our blood glucose levels aren’t normal.
One measure of our average glucose level over time is the A1C test. It’s not perfect, but we know that an A1C lower than 7% is correlated with a greatly reduced risk for heart, kidney, eye, and nerve problems. An A1C of 7% indicates an average blood glucose level over a 90 day period of 154 mg/dl, about 8.6 millimoles per liter.
How do we get to that 7% or below A1C? Well, I’ve posted many “how-to” videos over the past 10 years, but when it comes to just the blood glucose numbers, here are the recommendations. Your target for fasting blood glucose, like first thing in the morning or your blood glucose before a meal, is to be between 80 and 130. After meals, wait 2 hours before checking – the 2-hour after-meal target is 180 or lower. This is how we get to a 7% A1C. And hitting those targets most of the time is helped by medication, but WE MUST manage our diet and get some physical activity.
Look through my other videos - that’s what they’re all about. But understanding “blood sugar” first will help make more sense about why we focus so much on diet and exercise.
Leave your comments or questions below – hope this helps you understand what we’re all trying to accomplish.
Cheers to your health! We’re all in this together.
Don't forget to take a look at our most frequently asked questions.
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