Blood Sugar

We all know that heart disease kills more Fire Fighters than all other causes of line of duty deaths put together. It is a significant problem for us, and not only does it cost the lives of our brethren, it costs our employers and ultimately the taxpayers a metric shit ton of money annually.  So what gives? It’s no big secret, all you have to do is watch ten minutes of TV and you will see adds for fifteen different drugs and “heart healthy” food choices all promising to ward off the dreaded myocardial infarct. So how does something as obvious as heart disease keep sneaking up on us? If we are so savvy about prescribing drugs and recommending diets to would-be victims how can it still be the leading cause of line of duty death?  Would it surprise you to know that almost 50% of first time hearth attack sufferers had “normal” cholesterol and blood glucose lab values? Would it surprise you to know that blood glucose is a predictor of hearth disease? It surprised me…


I have already written about cholesterol and problems with using it’s most basic metrics as a measure of heart disease risk so I will leave it alone in this post. The focus here, as the title indicates, is blood sugar.


When we think blood sugar we think diabetes and Wilford Brimley, but it turns out that nearly 70% of all diabetics die from heart disease. It stands to reason then that being diabetic greatly increases your chances of developing heart disease, 2-4 times in fact. So what exactly is diabetes? Simply put, it’s a disease process that ends with your body not being able to regulate its blood sugar. Whether it is type 1 or type 2, essentially your body lacks the ability to produce sufficient amounts of insulin to clear sugar from your blood. This could be because the beta cells in the pancreas that secrete insulin are damaged from genetic and environmental factors or the body has been subjected to so many blood sugar spikes that the cells have become insulin resistant. Either way, eventually, this lack of effective insulin leads to chronically high blood sugar, which wreaks havoc system wide. Elevated blood sugar is associated with thickening of arterial walls, elevated triglycerides, elevated small dense LDL, low HDL, and systemic inflammation, all of which are associated with increased risk of heart disease. Studies published in the last 4-5 years have shown such direct correlation between heart disease, insulin resistance/diabetes, and the subsequent elevated blood sugar, that some forward thinking health screeners are predicting cardiovascular disease up to 20 years out using measures of average blood sugar. All of this is pointing to an obvious conclusion that maintaining “normal” blood sugar is a great way to reduce risk of heart disease. So how do we do that?


I will give you a hint of what not to do: What do you give a diabetic patient with low blood sugar if they don’t quite need D50? That’s right, orange juice, or milk. Add some “heart healthy” Honey Nut Cheerios and you have an American Diabetic Association (ADA) recommended breakfast.     


The next question has to be what is normal blood sugar? But first we need to cover the three common ways it is tested and to do that I will quote Chris Kressor.


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.

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 “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.

Each of these metrics has its own problems and inaccuracies but the underlying issue is that lab values are set by people and are innately arbitrary. For instance, in the OGTT if your 2 hour test number comes back at 139mg/dl you are good to go, no diabetes here. Why? Because you tested one point under the cutoff. This might be ok if the arbitrary cutoffs were set at a very conservative number where there was little chance of the patent having diabetic symptoms. Unfortunately this is not the case. The original numbers were set by a committee in 1978 who was tasked with determining a black and white line in the sand when in came to diagnosing diabetes. The reason being that, at the time, it was very difficult for people to get health and life insurance if they had been diagnosed with diabetes because the current pharmacological therapies weren’t effective. This led the group to set the cutoff so high that anyone who hit it was sure to be very much diabetic with little hope recovery. The ADA reviewed the literature again in 1998 and made a few slight adjustments to FBG values setting the new normal at <126mg/dl. Unfortunately they left out the part that shows a near doubling of heart disease risk between FBG levels of <100mg/dl and 110mg/dl.


So if you get blood work done that includes a standard lipid and metabolic panel and the values all read “normal” except for a slightly elevated FBG, circa 101mg/dl, odds are you are at significant risk for heart disease and no one will catch it.


What to do what to do?

It is pretty clear in the literature that keeping you blood sugar under 140mg/dl at all times is imperative. Even short duration exposure to that amount of circulating sugar can cause permanent damage to the body. So how do you know if you hit 140? Should you just eat very low carb all the time and hope for the best? That’s one way but what we in the fire service might find is that even with a low carb diet our blood sugar regulation gets knocked out of whack all the time by sleep deprivation, chronic and acute stress, significant exposure to toxins, and so on. I think it is important to take charge of our own future and in this case we have a cheap and easy tool to help us keep tabs on our blood sugar. Enter the glucometer. Whether you have one on the engine or you go buy one from Walmart get your hands on one of these and follow the protocol laid out below.


Step one: test your blood sugar

  1. 1.  Test your blood sugar first thing in the morning after fasting for at least 12 hours. Drink a little bit of water just after rising, but don’t eat anything or exercise before the test. This is your fasting blood sugar level.
  2. 2.  Test your blood sugar again just before lunch.
  3. 3.  Eat your typical lunch. Do not eat anything for the next three hours.
  4. 4.  Test your blood sugar one hour after lunch.
  5. 5.  Test your blood sugar two hours after lunch.
  6. 6.  Test your blood sugar three hours after lunch.

Record the results, along with what you ate for lunch. Do this for two days. This will tell you how the foods you normally eat affect your blood sugar levels.

On the third day, you’re going to do it a little differently. On step 3, instead of eating your typical lunch, you’re going to eat 60 – 70 grams of fast acting carbohydrate. A large (8 oz) boiled potato or a cup of cooked white rice will do. For the purposes of this test only, avoid eating any fat with your rice or potato because it will slow down the absorption of glucose.

Then follow steps 4-6 as described above, and record your results.

Step two: interpret your results

If you recall from the last article, healthy targets for blood sugar according to the scientific literature are as follows:

Marker Ideal*
Fasting blood glucose (mg/dL) <86
OGGT / post-meal (mg/dL after 1 hour) <140
OGGT / post-meal (mg/dL after 2 hours) <120
OGGT / post-meal (mg/dL after 3 hours) Back to baseline
Hemoglobin A1c (%) <5.3


Hemoglobin A1c doesn’t apply here because you can’t test it using a glucometer. We’re concerned with the fasting blood sugar reading, and more importantly, the 1- and 2-hour post-meal readings.

The goal is to make sure your blood sugar never rises higher than 140 mg/dL an hour after a meal, drops below 120 mg/dL two hours after a meal, and returns to baseline (i.e. what it was before you ate) by three hours after a meal.

There are a few caveats to this kind of testing. First, even reliable glucometers have about a 10% margin of error. You need to take that into account when you interpret your results. A reading of 100 mg/dL could be anything between 90 mg/dL and 110 mg/dL if you had it tested in a lab. This is okay, because what we’re doing here is trying to identify patterns – not nit-pick over specific readings.

Second, if you normally eat low-carb (less than 75g/d), your post-meal readings on the third day following the simple carbohydrate (rice or potato) challenge will be abnormally high. That’s why your doctor would tell you to eat at least 150g/d of carbs for three days before an OGTT if you were having that test done in a lab.

If you’ve been eating low-carb for at least a couple of months before doing the carbohydrate challenge on day three of the test, you can subtract 10 mg/dL from your 1- and 2-hour readings. This will give you a rough estimate of what your results would be like had you eaten more carbohydrates in the days and weeks leading up to the test. It’s not precise, but it is probably accurate enough for this kind of testing.

Step three: take action (if necessary)

So what if your numbers are higher than the guidelines above? Well, that means you have impaired glucose tolerance. The higher your numbers are, the further along you are on that spectrum. If you are going above 180 mg/dL after one hour, I’d recommend getting some help – especially if you’re already on a carb-restricted diet. It’s possible to bring numbers that high down with dietary changes alone, but other possible causes of such high blood sugar (beta cell destruction, autoimmunity, etc.) should be ruled out.

If your numbers are only moderately elevated, it’s time to make some dietary changes. In particular, eating fewer carbs and more fat. Most people get enough protein and don’t need to adjust that.

And the beauty of the glucometer testing is that you don’t need to rely on someone else’s idea of how much (or what type of) carbohydrate you can eat. The glucometer will tell you. If you eat a bowl of strawberries and it spikes your blood sugar to 160 mg/dL an hour later, sorry to say, no strawberries for you. (Though you should try eating them with full-fat cream before you give up!) Likewise, if you’ve been told you can’t eat sweet potatoes because they have too much carbohydrate, but you eat one with butter and your blood sugar stays below 140 mg/dL after an hour, they’re probably safe for you. Of course if you’re trying to lose weight, you may need to avoid them anyways.

You can continue to periodically test your blood sugar this way to see how you’re progressing. You’ll probably notice that many other factors – like stress, lack of sleep and certain medications – affect your blood sugar. In any case, the glucometer is one of your most powerful tools for preventing degenerative disease and promoting optimal function.

If you are fascinated by all this blood sugar talk check out the following links:


5 Responses to Blood Sugar

  1. […] most cases, it can be treated with lifestyle, nutrition, and exercise changes. As I wrote about in Blood Sugar, this is huge for reducing the risk of heart […]

  2. […] is nice but I would recommend checking your blood sugar to see if its nice to YOU, it doesn’t work for […]

  3. […] wrote about testing blood sugar levels as a way of gauging how your body deals with carbohydrate (CHO) a few weeks ago and I plan […]

  4. […] For this path it is recommended that you track blood lipids and blood sugar under the direction of your doctor; absent blood work, you can use body composition, which tends to […]

  5. ts cams says:

    You actually make it seem so easy with your presentation but I find this topic to be
    actually something that I think I would never understand. It seems too complicated and extremely broad
    for me. I am looking forward for your next post, I’ll try to get the hang of it!

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