Date with the Devil II… Testing Glucose Tolerance

After following a ‘low carb paleo’ meal plan and lifestyle for a couple of years, I decided to perform a Oral Glucose Tolerance Test (OGTT).  I’d been following a paleo or primal lifestyle and I wanted to test to see how my body would respond. Why?

  • Ultimately to see if I was still diabetic, at least according to this standard medical test.
  • To see if my body would ‘switch” from fat adaptation to glucose adaptation.


An Oral Glucose Tolerance Test is often given to people to determine if they are diabetic. The protocols differ slightly but in general,=people are given 75 grams of sugar (glucose). Their blood sugar levels are tested one and two hour post sugar consumption.



Please Do Not Try This

Unless you are like me… 


1) Have truly Normal Blood Sugars,  sub 100 mg/dl over night fasting blood sugars.

2)  You have broken the carb (grains and sugar) addiction for at least two months.

… even still I do NOT recommend this… ok? 


Testing Insulin Resistance and Glucose Intolerance …  The Plan

Back in December I had a “Date with the Devil?“, it was a 24 hour experiment with very high carb.  This is like that… only different. :)

* This is a TEMPORARY experiment.

** Luckily, I have a Continuous Glucose Monitor to record it … :)

(I am in Phase 3 now)

Phase 1 –  Eating a strict, ‘low carb paleo’ meal plan for 30+ days.   Here’s a post, “Nagging Question”  but in summary I ate only meats and leafy green vegetables.

Phase 2 –  Re-Adapting my body to  carbohydrates…. or adding back the carbs.  I gradually added back carbs in my diet.

Why am I doing it?  In brief, for almost three years I have eaten a Very Low Carb meal plan. My body has adapted to burning ketones for fuel.  To properly test my insulin resistance, I need to re-adapt my body to burning carbohydrates.

“… if you take an oral glucose tolerance test you will fail and be labeled diabetic.”

The quote above is from Petro Dobromylskyj’s  excellent description of why in this blog post, “click here“. (Thanks to Michelle Trevino for reminding me of Peter’s Post)  I totally disagree with the title and the phrase “Physiological Insulin Resistance”,  I prefer to call it ‘carbohydrate sensitive’ instead. :)

Phase 3 –  According to Peter’s protocol (I’ve read this on numerous Medical Industry sites as well) I will eat 150g of carbs for three straight days.     Then on the fourth day I will take a ‘home version’ of the Glucose Tolerance test, I will consume 75 grams of sugar to test my insulin resistance and glucose intolerance.

I am actually in Phase 3 now.

To summarize why I am adding back carbs …   Our bodies are designed to run on lower carb diets, of that  I have no doubt.  To test my body’s Glucose Tolerance, I must re-adapt my body to eating a higher carbohydrate meal plan.

…  here is how that’s working for me.  No shocker here… blood sugars begin to rise.




From the picture below you can see that I have indeed added back the carbs and as expected my blood sugars begin to rise.

Line 1 = my carbohydrate consumption.

Line 2 = My average blood sugars for the day using a Continuous Glucose Monitor (CGM).  The unit reports my blood sugar levels every 5 minutes.   Honestly, I do not like this experiment and will end the high carb phase in two days.  What you can not see, is the high blood sugar spikes I have experienced after eating the carbs. I’ll definitely report more on all this as time allows.



1.  Starting on April 25, I began adding starches to my diet, white potato and rice.

2.  April 30th I performed a  preliminary ‘home version of the Glucose Tolerance test.

3.  Here is an explanation and more background on the Glucose Tolerance Test,  in short it’s consuming 75 grams of sugar.  At the end of two hours if your blood sugars exceed 200 mg/dl, you are considered diabetic.  If you are below 140 mg/dl you are considered ‘normal’.  If you are between 140 mg/dl and 200 mg/dl you are considered to have  ‘impaired glucose tolerance’.

(I will post about that …and much more later)

* These results are from a Continuous Glucose Monitor (CGM). As several Type 1’s have mentioned (and as I have experienced myself) the CGMs are not 100 % accurate.  In my experience, when blood sugars are steady the accuracy seems very good.  However, when intense exercise or more carbs are consumed and blood sugars begin to rise rapidly, the accuracy seems to suffer.

** Even ‘standard’ blood sugar meters are not 100% accurate. Also, blood sugar levels are influenced by a wide variety of factors including foods, stress, sleep, infections and illness. Therefore, your experiences will be different.


Post Summary

There is only one real purpose for all this …  so that I (and you) can learn from the experience.

The main thing I want to learn… am I still insulin resistant and if so,  how much? … am I still technically a ‘diabetic’?

11 thoughts on “Date with the Devil II… Testing Glucose Tolerance”

  1. Amazing results. I wonder how long on a high carb diet before you’d start getting unnacceptable numbers again?

    1. Thank you. :) For me… they are already unacceptable numbers to be honest. I spend too much time above 100mg/dl.

      I can’t wait for this to be over… I love my sub 100 mg/dl world. :) I do occasionally go over 100mg/dl but it’s usually brief.

  2. And again, you are there PROVING what the ADA and others are advocating is antithetical to the goal of lower blood glucose.

    Putting yourself on the line for the betterment of society… Nicely done, sir

  3. Wow, Steve, you know what you’re doing? It’s called Science, Baby! May I suggest that you record all the parameters you measured and then provide all the raw data for all to see. It doesn’t have to be on a neat chart but I guess you’ll do that anyway, right? :) I think I see an association between carb intake and average BG. The first four days gives 91.75 BG avg for 27.5 carb intake avg. The next four days gives 101 BG avg for 93.5 carb intake avg. There’s an association alright. This suggests we could determine carb intake just with BG avg, and conversely predict BG avg with carb intake. You could also fiddle with the association between high/low BG and carb intake.

    I’ll keep an eye on your future posts.

    1. Thanks Martin, re: science… BG is tricky because not only foods but stress, sleep, exercise, infections and sickness etc all have an effect.

      I could make a comment that I’m doing more ‘science’ than many studies… butt i won’t. :)

      I am actually logging all the information now by days and recreating events.

      High Low… I can and will reproduce that. You will see what I am talking about when I create the post but the CGMs are far from accurate when consuming a relatively high number of carbs.

  4. Steve, thanks for a great website, I wish I’d have found it sooner, it would have saved me a lot of time studying.

    A couple of months ago, I was diagnosed with type 2, metabolic syndrome, etc. Our situations were almost identical except my glucose was only 240.

    I quickly came to pretty much the same conclusions you did and got my sugar under control in about two weeks. I expect to be drug free by July at my next blood test.

    Your site really helped me steepen my learning curve over the last week or so.

    Thanks again. You Da Man!

      1. What’s so frustrating about this episode is that the answers are so simple, yet so well surpressed. (you know that, eh?)

        My doctor was prattling on about there being a “diabetes & obesity epidemic”, and I asked him, “Why?”

        He answered, “We don’t know.”

        Bullpooie. If a glorified mechanic (contractor) can figure it out in a few days, they know, but there’s no money in that.

        I’ve spent my entire adult life evading doctors, and now that they’ve captured me, I’ll spend the rest of it trying to break out of their pill prison.

  5. Steve, I am curious as to why you did not add low glycemic carbs back instead of the high glycemic such as white potatoes and rice. I am on a Paleo diet and my sugars are slowing coming down. However I would like to have a 1/2 of a sweet potato or some quinoa or steel cut oatmeal eventually. I will be looking for those things that do not raise my sugar too much. But until then I can still enjoy my coconut flour pancakes or nut and seed crackers that I make! Who knows maybe I will never eat starch or grains again! Thanks for your great information!

    1. Thanks for the comment and you are welcome. :) For the glucose tolerance experiment, I really wanted to eat as close to 150g of starch/sugar … to make sure I was fully adjusted/adapted. Some sites suggested even 200g of carbs… I wasn’t going that high.

      I do plan on testing some of the foods you mentioned including sweet potato and maybe some oats. I definitely want to try breads as well but space them out … so that I don’t over tax my pancreas.

Comments are closed.