Last week, we started a series on blood glucose and why you should care about it. We talked about how pre-diabetes is NOT just a disease affecting the obese, but can actually affect endurance atheltes at nearly the same rate as non-athletes. We talked about the general physiology, types of sugars, how to read labels and the basics of how to measure your blood glucose levels. If you missed that post, make sure you take a moment to read it, especially if this topic is new to you.
This week, we’re going to dive a little deeper. You heard me say last week that ‘If there is one single thing you can do to discover your own personalized diet and monitor your own health over time, it is to use a blood sugar meter regularly.’ But a common question I get is ‘now that I’ve tested my fasting blood glucose for 7+ days, now what?’
There are 3 different scenarios that can happen once you’ve taken your fasting blood glucose for 7+ days in a row…
1- your average fasting blood glucose is falling between 80-99mg/dL which is IDEAL!
2- your average fasting blood glucose is all over the board. Some days it’s higher than 99mg/dL, some days it’s lower than 80mg/dL and some days it falls right in the middle.
3- your average fasting blood glucose is consistently above 99g/dL.
If scenario 1 is your reality, AWESOME! If you love the diet you are currently following, then I recommend you stick with it and just check your blood glucose levels every 3-6 months to make sure you are staying in a healthy range.
However, if you're eager to find out how your blood sugar responds to different types of carbohydrates, then you can use your blood sugar meter to test that by completing a carbohydrate tolerance test. The instructions for carbohydrate tolerance testing can be found below, but I highly recommend that you read the “Glucose v. Fructose” section before moving onto the carbohydrate tolerance section.
If scenario 2 or 3 is your reality, then I recommend jumping onto a lower carb diet for 30 days.
You can read more about ‘How blood sugar can go WRONG’ from last week's blog. While you transition to a lower carbohydrate diet, you might feel hungrier and experience some symptoms. This is why I recommend eating smaller meals more frequently during the transition. Instead of eating 2-3 balanced meals per day (which is what I recommend when your blood glucose is stable), I would eat 3 smaller, low carb meals and include 2-3 small low carb snacks between them.
Some of my favorite low carb snacks are:
After 30 days of lower carbohydrate eating, test again.
You might also notice during these 30 days that your urge to snack starts to go away. This is a sign that your blood sugar is starting to stabilize and is a great sign! Follow your hunger signals and transition to eating 2-3 low carb meals per day as you start to experience less hunger.
If your new 7+ day fasting blood glucose tests average between 80-99mg/dL, and you miss having more carbohydrates in your diet, it’s time to complete a carbohydrate tolerance test! But before we jump into exactly how to do that, first let’s briefly talk about carbs and sugar.
Glucose vs. Fructose
Not all carbohydrates are created equal. The way our body processes 50g of sweet potato is not the same as if eating 50g of high fructose corn syrup. But to keep things simple, let’s just talk about monosaccharides. These are typically known as “simple sugars” and they are the most basic units of carbohydrates. Examples of these are glucose, fructose and galactose.
Glucose and fructose are the two most common types of sugars contained in natural foods. Glucose is found in most of the starchy foods, such as potatoes, rice, breads and pasta. Glucose is the preferred fuel for the cells of our body, including the cells in our brain. Glucose is absorbed into the bloodstream within our small intestines. If the body needs energy immediately, the ingested glucose can be used by the muscles and/or brain right away. If the body does not have an immediate need for glucose, it is stored in the liver or in our skeletal muscles. The liver and the skeletal muscles can only store a limited amount of glucose. Once these stores are full, the liver converts excess glucose into fat and stores it in adipose (fat) tissue.
Fructose is found naturally in fruits and some vegetables. Fructose consumed in large quantities can be toxic to the liver. Excess fructose consumption is known to create fatty liver disease which leads to insulin resistance and obesity. It has been shown that overeating fructose can cause insulin resistance within one week and only eight weeks to become pre-diabetic.
Additionally, fructose does not provide a signal of satiety. If you were to eat 500 calories of a potato, you would feel very full. Drinking 500 calories of soda containing high fructose corn syrup does not create this same feeling of fullness, causing overeating. If we are not feeling the satiety sensation, you can see how easy it is to over eat and potentially create newly formed fat.
I'm not suggesting that fructose is bad. What I am suggesting is that too much of anything is bad. Too much glucose is bad. Even too much water is bad. But how much is too much? In this situation, that depends on your body. And one way to help you discover that is by doing a carbohydrate tolerance test, so let’s jump into that...
Carbohydrate Tolerance Testing
For many people, the amount of carbohydrates and sugars that have been consumed over the course of their lifetime is excessive. The excess consumption of these carbohydrates has led to irregular blood sugar which can lead to lethargy, excess body fat retention, fatigue, poor sleep, and less than optimal health. If after testing, you’ve established that your blood sugar is normal, you can complete a carbohydrate tolerance test to learn what life can be like when you consume healthy forms of carbohydrates in the appropriate amounts for your body. (In other words, what it is like to eat balanced.)
In Robb Wolf’s book, Wired To Eat, he details a process he calls ‘the 7 Day Carb Test.’ Your blood glucose levels rise and fall when you eat a meal containing carbohydrates. How high it rises and how long it stays high depends on: the quality of the carbohydrates; the quantity of carbohydrate; and your own bio-individuality. In order to learn how your own body responds to the quality and quantity of carbohydrate, you should consider a carbohydrate tolerance test.
During this test, you use a blood sugar meter to test your body’s personal tolerance to 50g of effective net carbs to a specific food. The point of completing this type of test is to learn more about how your body can properly handle (or not handle) different types of carbohydrates. It might surprise you that some people can tolerate sugary pastries better than a banana, but it is true. This is bio-individuality at its finest. As Robb says in his book, “finding the ‘right’ carbohydrate(s) for your body allows you to dial in your specific carbohydrate tolerance and therefore keep our hormonal profile in a state that is favorable for fat loss while repairing our metabolism.’
How to test
The most important things to look for (that would indicate that the carb is not the best carb for your body) are:
If your blood sugar goes much above 120 mg/dL at the 2 hour mark of the test, this can be a sign that your blood sugar has “spiked” and this is not an ideal carb for you. It would be expected that your blood sugar would then drop rapidly, causing you to feel poorly.
The opposite is also true. If your blood glucose reading at the 2 hour mark is below your fasting reading, this is just another sign of the wrong carb for your body.
Ideally, you want to find a carb that doesn’t make you feel badly, and that brings your blood glucose level up (no higher than ~115 mg/dL), and has a slow decline over the next 4 hours.
GIVE THE CARB TOLERANCE TEST A TRY!
Using a blood glucose monitor is by far the easiest way to get insight on how your body is handling the sugar that you eat. And running a carb tolerance test allows you to get even clearer on what specific carbohydrates work for you (and vice versa).
Next week, we’ll dive even deeper into knowing how to use the carbohydrates that are best for your body at the right times of day so you keep stable energy and not store them as fat!
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Tiana Rockwell is a certified nutritional therapist, avid endurance athlete and dark chocolate lover. She believes that by eating REAL food, we can balance our body and reach optimal health and wellness!