I discovered that you can buy a 2 week Continuous Glucose Monitor (CGM) for $65, more details here:
Here is an example of a typical day of my measurements:
I’ve been doing the ‘time restricted’ eating thing for about a year, with a eating window between 6pm -> 10pm. The rise between 9 -> 10 am is from a morning exercise routine.
Here is a summary for 2 weeks of a mostly consistent routine:
For another 2 weeks, during the post-exercise afternoon fasting window, I tested how my blood sugar reacted to 100 calories of 30 different foods.
These photos are sorted by weight, scale is in ounces:
Butter 
Peanut Butter 
Chocolate 
Peanuts 
Sugar 
Raisins 
Mullberries 
White Bread 
Whey Protien Bar 
Avocado 
Hummus 
White Rice 
Cottage Cheese 
Yogurt 
Buckwheat 
Bannana 
Red Wine 
Eggs 
Purple Potatoes 
Grape Juice 
Oatmeal 
Blueberries 
Granny Smith Apple 
Red Delicious Apple 
Apricots 
Grapefruit 
Carrots 
Peaches 
Strawberries 
Watermelon
Putting 100 calories of various foods on a scale really made an impression my naïve stomach. A full bowl (10 oz) of delicious strawberries has the same calories as a handful of peanuts, or 0.7 oz of peanut butter or chocolate!
I downloaded the data from libreview.com (button on upper right of glucose history page), then imported to this google sheet. I manually tweaked each test to make these charts, sorted with highest peak first:
As expected, the high sugar foods and fruits had the highest peaks. Raisins and grape juice had similar peaks to pure sugar! I used to love raisins 🙁
Also as expected, high protein or fat foods were pretty flat. An interesting note is that wine was also flat, even though it is basically fermented grape juice.
The amount of sugar is what determines the peak response. Here are 50, 100, and 200 calories of raisins, corresponding to 11, 22, and 44 grams of sugar:
Mixing in a high fat or protein food seems to help blunt the sugar response a little. Here is bananas & yogurt:
Here is raisins & peanuts:
So what is my take away? Blood sugar spikes trigger the release of insulin, and if this happens too often, you become numb to it. This is what leads to diabetes, so minimizing spikes seems like a good idea.
For my body, this means avoid eating foods with 15+ grams of sugar (e.g. a handful of raisins). Eating bulky high fiber fruits is good (fills me up) as long I limit it to one serving and/or mixing it in with other foods.
But every body is different (e.g. muscle mass, gut biome), so your mileage may vary. The only way to know for sure what can raise your blood sugar level significantly is to measure it. Don’t let the needle scare you 🙂
Bruce
That was very revealing. I notice that too much sugar makes my stomach ache. For instance, pancakes with maple syrup. So I’ll eat whole wheat pancakes instead to have a little less blood sugar spike. So a teaspoon of sugar is 4.2 grams, then one should limit oneself to three teaspoons of sugar at a sitting.
How is your breathing? Do you breathe through your nose or your mouth. Have read and have been re-reading a book on breathing and have been incorporating breathing exercises into my daily routine. I’ll send you a copy if you’re interested.
I bet that is James Nestor’s book, Breath: The New Science of a Lost Art. I have not read it, but have listened to several podcasts with him. I mostly do nose breathing, but struggle doing it when exercising.
I am very interested with your experiments. I don’t have such a device and measure sugar with ordinary glucose meter is difficult. But when the technology will improve and permanent measurement becomes more achievable, I will do the same.
Give my love to your family
Thank you for posting result of your experiment. I will get BT version.
Thank you very much for posting your experiment!
May I ask what is you HbA1c (or what it was at the year you’ve done this cgm experiment? If you don’t want to post it, would you at least say if you’re prediabetic?
I’ve done a bit of experimenting with a Libre 2 and noticed that adding fibers or fat, indeed seems to blunt the glycemia peak, but only temporarily. After a few hours, I get a peak anyway. Did you notice that?
Sorry for the mistakes in the above message. My internet took a break and when it came back I posted the message without realizing I had not completed it, nor corrected it. Here, what it should have been :
Thank you very much for posting your experiment!
May I ask what is your HbA1c, or what it was at the year you’ve done this cgm experiment? If you don’t want to post it, would you at least say if you are prediabetic?
I’ve done a bit of experimenting with a Libre 2 and noticed that adding fibers or fat, indeed seems to blunt the glycemia peak, but only temporarily. After a few hours, I get a peak anyway. Did you notice that? Thank you very much!
My HbA1c is good and consistent at 5.1. Since doing this experiment I seen quite a few others note that it is best to eat carbs after fat & protein as a great way to limit the peak glucose. My metabolic health is pretty good, probably partly because I have been doing time restricted eating (mostly from 4 pm -> 6 pm, with some snacking from 6->8), so I do not see much of a peak.