Let the ‘sciencing’ begin…
I have had my fasting blood sugar tested on several occasions, most recently a few months back. I hadn’t been in the gym in a few months (so far my longest break from the gym), and I was getting exhausted after eating meals that were less than healthy. My doctor wanted to test to see if I was diabetic. This wasn’t the first time I had had this test done and it always comes back fine. So on September 14, 2015 my fasting glucose was 5.0 mmol/l (to convert to mg/dl go here). Not perfect, but within the range of normal.
I have always been suspicious of the fasting glucose test because I am more curious as to how my body deals with foods shortly after I eat, not after 12 hours. I feel fine in the morning, but tired after a big meal… what is going on that is making me tired?
I have been thinking I should get a blood glucose meter and test myself for quite awhile. I finally decided to do just that. My doctor suggested that this may be a waste of time. The pharmacist I purchased this device from had a very similar, although much stronger opinion.
I am going to shorten the comedy of errors that was my learning process to determine when to take blood sugar readings and what those readings should be in non-diabetics.
The key times to take blood are before eating (first time of the day is your fasting), 1 hour after, 2 hours after and in some cases 3 hours after.
Here is a graph of blood sugar readings taken on the hour in healthy adults. It was created as part of a study that can be found here.
The main thing to see in the chart is the average glucose concentration in the blood. That is the blue line that starts at about 4.4, tops at about 7 at about 8:15, 45 minutes after eating, and then drops quickly to about 5 at 10:00. That is what a healthy blood sugar reading should be.
There is a pretty good website that helps a healthy person determine what their blood sugar readings should be and why. It is here.
Some of the important things to take away from this site:
Normal Fasting Blood Sugar
Fasting blood sugar is usually measured first thing in the morning before you have eaten any food. A truly normal fasting blood sugar (which is also the blood sugar a normal person will see if they have not eaten for a few hours) is:
Between 70 mg/dl (3.9 mmol/L) and 92 mg/dl (5.0 mmol/L) .
This is the finding of a considerable body of research. People whose blood sugar tests at this level do not develop diabetes over the next decade or longer. Those with supposedly normal blood sugars above 92 mg/dl often do. Nevertheless, most doctors consider any fasting blood sugar below 100 mg/dl (5.6 mmol/L) as completely normal
Post-Meal Blood Sugar (Postprandial)
Independent of what they eat, the blood sugar of a truly normal person is:
Under 120 mg/dl (6.6 mmol/L) one or two hours after a meal.
Most normal people are under 100 mg/dl (5.5 mmol/L) two hours after eating.
This is demonstrated by the graph at the top of this page, which shows the blood sugars measured during a study where normal people had their blood sugar sampled every few minutes after eating a high carbohydrate meal.
I believe these numbers are actually really important to everyone who wants to be fit. I believe that unfit people who are not diabetic may run into blood sugar problems due to poor diet choices or lack of exercise. The website I listed above and others, although directed at diabetics talk about using your blood sugar to find foods that you shouldn’t be eating and eliminating them from your diet.
I think this part of the actual science behind the Zone diet (and pretty much every effective diet created after the Zone diet is based on the Zone diet). In the book, if I remember, Dr. Sears talks about how you can tell if you are reactive to refined carbohydrates. I think he probably mentions a test, but recommends just looking in a mirror. The gist of it is, if you are overweight, you probably have a problem with refined carbs/starches.
So, it is my theory that there is a continuum of effectiveness of insulin efficacy and it runs from perfect to diabetic. I believe that at least a large subgroup of unfit people fall just outside the diabetic zone. Part of this, I believe, manifests itself in that unfit people eat meals that push their blood sugar out of the optimal zone. They do this regularly and these are the food items that they shouldn’t be eating. I think this can be measured using a blood sugar monitor and I intend to try. It is quite possible that this has already been proven in general, but I would definitely like evidence on what pushes my blood sugar out of the zone.
I have so many questions though… does mixing up the order of what you eat help? Ie. If I ate a salad first, or ate my vegetables before my refined carbs/starches. If it does, how much time should I leave between vegetables and refined carbs? How do overall calories effect your blood sugar? Is blood sugar effected almost exclusively by overall carb load in a meal? Does walking after eating bring your blood sugar down faster than sitting? How about exercise? If I ate the same thing at the same time as a healthy person, how would our blood sugars differ? Does diet pop effect your blood sugar after eating? (I am beginning to try these experiments, so if the question is in the form of a link, you can find the results there).
I am sure this is only the tip of the iceberg in terms of questions that I have. I am going to create some simple experiments to try to answer some of these questions. I have had the meter for a few weeks and one problem is that I almost never remember to test my blood 3 times in a row on the hour. I will shoot for before meal, one hour, and two hours… sometimes I will get the 3rd hour. I might need it, judging from some recent readings.