Pre-diabetes and Home Carbohydrate challenge

Okay, so I am typing this up mostly for my own benefit, but since I couldn’t find similar information elsewhere I figured I would supply it to others as well.

I am an engineer by training, practical by nature, and a researcher by profession. I have had what I call a ‘malfunctioning pancreas’ for as long as I can remember. Growing up I suffered from reactive hypoglycemia which my father (but not my doctors) claimed could be a precurser of diabetes. I eventually had three pregnancies with gestational diabetes (and over 9 lb babies). Since then I have had very slowly creeping up sugars (A1c after my first pregnancy was 5.6 and most recently was 5.9). This despite having exercised like crazy, eaten reasonably well and never having been over-weight. So, I have been very frustrated by a feeling that I am just “waiting” for my pancreas to finally give up and lose the battle to maintain my sugars. I have done a lot of research on what my body SHOULD be doing and I finally designed an experiment to find out what my body was ACTUALLy doing after eating a lot of carbs.

This morning I ate a Einstein cinnamin raisin bagel with a little bit of butter and about 6 oz of milk (a total carb load of about 73 grams). I tested my blood glucose just before I started eating and then every 15 minutes afterwards. I was looking to see what my sugars did compared to the “typical” first and second phase described in the literature.

The results would be much easier to show with a plot, but here is what I found: Starting at a fasting BG of 82, I was at 101 at 15 minutes and peaked at 30 minutes with a maximum BG of 160 (so it looks like I gain a little bit more than 1 mg/dl for each gram of carbohydrate). I then followed a very linear progression down at a rate of -0.42 mg/dl per minute (or 25.2 mg/dl per hour) until the 2 hour and 15 minute point (111 at that reading). Unfortunately, I had to leave around then (I had originally thought the test would only take about 2 or 2.5 hours to get close to normal) and I missed the 2 hour and 30 min test. At about 2 hours and 45 minutes I was at 79 (and feeling kind-of shaky).

So, what did I learn?

  1. For those who are only interested in the 1 hour and 2 hour numbers, I was 143 at 1 hour and 123 at 2 hours. Certainly not normal, but also not diabetic.

  2. I had expected a sharp (although small) decrease after the peak before settling into a steady reduction in blood glucose levels. Instead, there was no sharp decrease - the data is remarkably linear from the peak to the 2 hr 15 min test. My simplistic interpretation of this is that I have no or a minimal first phase insulin response, but my second phase insulin response is working away by the 30 minute mark.

  3. I still have some of the reactive hypoglycemia problems lurking. When I was diagnosed with it, my drop came at the 3 hour mark and the drop from the 2hr 15min level of 111 to the 2hr 45min level of 79 was sharper than the previous data trend.

  4. Conclusion: I need to keep eating a low carbohydrate diet and checking my sugars periodically to make sure things haven’t gotten worse. (For those interested in creating their own plots, the data is as follows: times = 0, 15, 30, 45, 60, 75, 90, 120, 135, 163; BG = 82, 101, 160, 152, 143, 127, 134, 125, 123, 111, 79.)

Now, however, the researcher in me is completely unsatisfied by the limited set of conclusions I have from this data and I am left with several more questions:

  1. Is the linear relationship between sugars and carbs a constant at all times of the day? (I did the test first thing in the morning which is usually when I can tolerate the most carbs.)
  2. Is this linear relationship a constant independent of carb load? (If I eat only 25 grams will it still spike at 30 minutes and be removed at the same rate?)
  3. Does the sudden drop around 3 hours always occur, or only if my sugars are still above a certain level?
  4. If my sugars are higher than fasting, is the relationship between carbs and BG rise the same?

So, I am going to give my fingers a little break, but I have plans for the next test to learn more.

I am struck by the leisure of having a Cinnamon - Raisin Beagle and Milk. If I did that on Tuesday, I would still be fighting my high blood sugar on Friday. I would love a recovery period like that.

Still i do think you raise some great points.I have never tried to see the arc of my blood sugar going up and down. Perhaps it is something to look at just for fun. In the mean time pass the Beagle, Milk and the recovery time. That sounds pretty darn good.

Interesting CQJ!!
I mentioned the time frame I refer to as pre-diabetes when I was hypoglycemic to my doctor, and (why am I not surprised) she replied, "hypoglycemia is not pre-diabetes and it does not lead to diabetes". I really am weary of few are adequate...never mind good or even great.

Thanks for the comments! I was actually pretty happy with my recovery time. I am not very patient, unfortunately, and I sometimes catch myself wishing my pancreas would just hurry up and get on with it rather than leaving me in this in-between state. I appreciate this site in part because it reminds me that I should be very pleased to be in my current state. Thanks!

I do like to understand what is going on and I plan to continue to do my best to learn. I plan to repeat this test at intervals of 2 to 3 months as a way to keep myself eating low-carb and to be able to track how my pancreas is doing. Now I have a way to celebrate it doing well, rather than wondering when it will fail.

My guess is that the milk has some fat in it and if you had butter on the bagel that would slow things down a bit. After reading this blog I thought I'd try a modified experiment, but I decided to us a straight sugary drink of 75 grams of sugar...not High fructose corn syrup. Yes,I am doubting myself! I also tested at 30 minutes instead. Results are:
Fasting 104
30 min 199
60 min 163
90 min 129
120min 109
So, it appears to me that I also have lower basal insulin (think that is the name?) and a lowered first insulin response, but the second one that kicks in after 30 minutes is able to clear the glucose to within normal range at 2 hours. I'm suspecting this is why I passed the GTT tests completed several years ago. My pre-D diagnosis only came about recently from the higher fasting readings. I guess the higher fasting are a refelction of the low first insulin and basal.

I actually learned later that the meter I used for this experiment was recalled for reading too low. So, I repeated the experiment also using a soda with 75g of sugar (and measuring every 30 minutes). For comparison, here are my results:
Fasting 87
30 min 156
60 min 184
90 min 118
120 min 76
It looks to me like our results are very similar with a lower level first phase response and a strong second phase. Still, not normal results while not being diabetic by official standards.

Any idea on what the progression is when the first phase is low? Just wondering if the fasting creeps up which leads to a diagnosis or the second phase dies out eventually leading to higher postprandial readings.

I don’t know. If I had to make a guess I would expect the second phase dying out would first lead to higher postprandial readings and eventually result in a higher fasting number. That’s based on what I’ve read about the progression. I try and keep an eye on my fasting numbers, even when I don’t track my post-meal numbers carefully. I figure I know I’m in trouble if my fasting gets too high.

hi CQJ, i am also pre diabetic with a 5.9 A1c in 2009, but i have been getting A1c's of 5.3- 5.5 with a low carb diet and exercise and no meds. i seem to have some numbers that are similar to yours. both my babies were over 8 lbs and i am 5'3". i never had a test for gestational diabetes as my pregnancies were in taiwan. but with the second child i did have a yeast infection during the pregnancy and within one year after the birth, so my bg i believe was starting to spike OGTT was 90 fasting, 165 at 30 min and 128 at one hour and two hours. this was done at a lab in dec. 2013. my lipids and blood pressure are all excellent. i do tend to gain weight around my abdomen like an apple, but i am not overweight. i put on muscle easily. my mother was diagnosed as Tpye 2, but went to full insulin within 5 years. my father is also diagnosed as type 2, but is doesn't control his diabetes well. he only take metformin, but has a lot of tooth loss and neuropathy.

the low tris i believe points to insulin sensitivity. i did genetic testing through 23andme and was found to have one risk allele for the most predictive gene risk allele for Type 2: TCF7L2, which is associated with a deficiency in insulin production, as well as colon, breast, and prostate cancer.