It’s been a long time. For the past five months, I was working on a COVID-related project that took up all of my spare time. The project just ended so I’m going to get back to the QD project.
To everyone who reached out over last few months, thank you. I really appreciated your kind words, questions, and encouragement. It was a big part of my motivation to start this back up.
Here’s the plan for the next few experiments/posts:
Complete analysis and write up final report for the food effect study
In addition to what I’ve already posted, I have data for corn starch, erythritol, inulin powder, and glucose+oat fiber.
Re-tune basal and bolus (meal) insulin doses
My routine has changed a lot due to working from home, changing doctors, and changing medication (due to insurance requirements). Plus, I was able to get a Dexcom G6 CGM, which is showing accuracy comparable to my blood glucose meter. Blood sugars are still good, but I think I can get them better.
Re-measure blood sugar impact of glucose and insulin; compare to previous data
While working from home, I’ve gained some weight (and hopefully muscle). This has resulted in a change in my insulin sensitivity. Not huge, but I need to remeasure to have an accurate baseline for future experiments.
This self-experiment is being done as part of the Keating Memorial Self-Research Project. A couple of other people from the Open Humans community are also running the same experiments. If you’re interested in joining in, let me know in the comments or send me a PM.
This post is an update on my experiments measuring the effect of food ingredients on blood sugar.
This is especially problematic for predicting the blood glucose impact of foods from their nutrition information as based on my data so far, even insoluble fibers can range in impact from 0.4 – 76% of glucose.
Next week I’ll finish out the major macronutrient groups with cornstarch. Still deciding where to go after that, but it will either be more ingredients used in low carb cooking (inulin, erythritol, soluble corn fiber, lupin flour) or mixtures of the major macronutrients (to measure combinations effects.
Details
Purpose
To quantify the effect of ingestion of food ingredients and ingredient combinations on my blood sugar.
Procedure. From 7 pm the day before through 4:30p the day of experiment, no food or calorie-containing drinks were consumed and no exercise was performed. Non-calorie-containing drinks were consumed as desired (water, caffeine-free tea, and decaffeinated coffee). At ~12 pm, the substance to be tested was dissolved or suspended in 475 mL of water and ingested as rapidly as comfortable. BGM measurements were then taken approximately every 15 min. for 2 h or until blood glucose had returned to baseline, whichever was longer. A final BGM measurement was taken 4.5 h after ingestion.
Measurements. Blood glucose was measured using a FreeStyle Libre flash glucose monitor and a FreeStyle Freedom Lite glucose meter with FreeStyle lancets & test strips. No special precautions were taken to clean the lancing site before measurement. To take a sample, the lancing devices was used to pierce the skin at an ~45 deg. angle from the finger. Blood was then squeezed out by running the thumb and pointer finger of the opposite hand from the first knuckle to the lancing site of the finger. Blood was then wicked into a test strip that had been inserted into the meter and the glucose reading was recorded.
Data Processing & Visualization. iAUC was calculated using the trapezoid method (see data spreadsheet for details). Data was visualized using Tableau.
Figure 1. Change in blood glucose vs. time for resistant starch and glucose tests.
Figure 2. Maximum blood glucose increase and iAUC vs. amount consumed. Red, orange, and blue indicate glucose, resistant wheat starch, and whey protein isolate, respectively. Lines are the best linear fit to the data.
Changes in blood glucose as a function of time for the resistant wheat starch and glucose tests are shown in Figure 1. For resistant wheat starch, I observe an increase in blood glucose starting at ~45 min. and reaching a peak between 75-120 min. While the timing is similar to that of whey protein, the magnitude of impact is much larger, with the peak change in blood glucose and iAUC increasing by 33% and 76% vs. glucose. It will be interesting to see next week how regular corn starch compares to resistant wheat starch and therefore if the chemical modifications to resist digestion are having any meaningful impact.
Put together, this indicates that resistant wheat starch is slower to digest than glucose, but contrary to the claims above, is clearly still metabolized to glucose. This is extremely disconcerting, as both oat fiber (iAUC 0.4% of glucose) and resistant wheat starch (iAUC 75% of glucose) are listed as insoluble fiber on nutrition labels, but have radically different impact on blood sugar. Given the lack of clarity and quantification of ingredient lists, this makes it nearly impossible to predict the blood glucose impact of a food without eating it and testing.
Next week I’ll finish out the major macronutrient groups with cornstarch. Still deciding where to go after that, but it will either be more ingredients used in low carb cooking (inulin, erythritol, soluble corn fiber, lupin flour) or mixtures of the major macronutrients (to measure combinations effects.
Apologies for the missed post this week. I’m helping out a company developing a COVID-19 test and didn’t have time to analyze & post my latest experiments. I’m still collecting data for the food effect study and will analyze and post results as soon as I have time.
I hope everyone is staying as safe and healthy as possible in these crazy times.
This self-experiment is being done as part of the Keating Memorial Self-Research Project. A couple of other people from the Open Humans community are also running the same experiments. If you’re interested in joining in, let me know in the comments or send me a PM.
This post is an update on my experiments measuring the effect of food ingredients on blood sugar.
This week, I have the results from whey protein and olive oil.
Summary
Olive oil had a negligible effect on my blood sugar, ~0.1 mg/dL/g(olive oil) for ~350 kcal of oil, or 1.5% that of glucose.
Whey protein isolate increases my blood sugar by ~20% that of glucose (by iAUC), but with a slower rise. This result sin a lower peak, 0.68 mg/dL/g(whey) or 10% that of glucose, but a long tail of increased blood sugar, ~0.4 mg/dL/g(whey) @ 4.5 h.
Still deciding what to try next, but it will either be corn starch (to have an example from each major macronutrient), resistant starch (fiber with disputed claims to non-digestibility), or combinations of protein, fat, or fiber with sugar.
Details
Purpose
To quantify the effect of ingestion of food ingredients and ingredient combinations on my blood sugar.
Ingredient Background
Whey protein isolate is a complete protein extracted from milk whey. It’s the most popular protein supplement due to its ease of digestion, rapid absorption, and appreciable content of all 9 essential amino acids.
Olive oil is a cooking oil that’s high in unsaturated fats, primarily oleic, linoleic, and palmitic acid. It’s used extensively in cooking.
Design/Methods
Procedure. From 7 pm the day before through 4:30p the day of experiment, no food or calorie-containing drinks were consumed and no exercise was performed. Non-calorie-containing drinks were consumed as desired (water, caffeine-free tea, and decaffeinated coffee). At ~12 pm, the substance to be tested was dissolved or suspended in 475 mL of water and ingested as rapidly as comfortable. BGM measurements were then taken approximately every 15 min. for 2 h or until blood glucose had returned to baseline, whichever was longer. A final BGM measurement was taken 4.5 h after ingestion.
Measurements. Blood glucose was measured using a FreeStyle Libre flash glucose monitor and a FreeStyle Freedom Lite glucose meter with FreeStyle lancets & test strips. No special precautions were taken to clean the lancing site before measurement. To take a sample, the lancing devices was used to pierce the skin at an ~45 deg. angle from the finger. Blood was then squeezed out by running the thumb and pointer finger of the opposite hand from the first knuckle to the lancing site of the finger. Blood was then wicked into a test strip that had been inserted into the meter and the glucose reading was recorded.
Data Processing & Visualization. iAUC was calculated using the trapezoid method (see data spreadsheet for details). Data was visualized using Tableau.
Figure 1. Change in blood glucose vs. time for whey protein and olive oil tests.
Figure 2. Change in blood glucose vs. time for whey protein and glucose for conditions with a peak of 20-25 Δmg/dL.
Figure 3. Maximum blood glucose increase and iAUC vs. amount consumed. Red, blue, and green indicate glucose, whey protein isolate, and olive oil, respectively. Lines are the best linear fit to the data.
Changes in blood glucose as a function of time for the whey protein isolate and olive oil tests are shown in Figure 1. As expected, olive oil showed no measurable impact on blood glucose at 40 g, or 350 kCal, consumed. Future experiments will look at whether it or similar oils can modulate the blood sugar response to ingredients that do impact blood sugar.
For whey protein, I observe an increase in blood glucose starting at ~45 min. and reaching a peak between 75-105 min. The magnitude increases with increasing amount consumed, but non-linearly; the difference between the 15 and 30 g consumed conditions is quite small. More data is needed at lower amounts consumed to see if this is a real effect or just noise in the data.
Comparing directly to glucose, for the same peak change in blood glucose, whey protein is much slower to impact my blood glucose and is metabolized over a much longer period of time. For example, looking at the conditions where peak Δmg/dL = 20-25 (see Figure 2):
Time to >5 mg/dL rise is 60 vs. 15 min. for whey vs. glucose
Time to return to <5 Δmg/dL is 255 vs. 120 min. for whey vs. glucose
Results are similar for all other amounts consumed. As show in Figure 3 and the summary table, this slower metabolism results in whey protein having a larger relative impact on iAUC than peak change in blood glucose (20 vs. 10% of glucose per gram). This may be do to giving my body more time to produce endogenous insulin, or even directly stimulating its production, reducing the peak blood glucose. Both of these effects have been reported. Given that, it would be useful to see the same measurements in someone with Type 1 diabetes, who does not produce endogenous insulin.
Conclusion & Next Experiments
Olive oil had a negligible effect on my blood sugar, ~0.1 mg/dL/g(olive oil) for ~350 kcal of oil, or 1.5% that of glucose.
Whey protein isolate increases my blood sugar by ~20% that of glucose (by iAUC), but with a slower rise. This result sin a lower peak, 0.68 mg/dL/g(whey) or 10% that of glucose, but a long tail of increased blood sugar, ~0.4 mg/dL/g(whey) @ 4.5 h.
Still deciding what to try next week, but it will either be corn starch (to have an example from each major macronutrient), resistant starch (fiber with disputed claims to non-digestibility), or combinations of protein, fat, or fiber with sugar.
I’ve been confined to my house for the past couple weeks due to the Bay Area’s “shelter-in-place” order, so I’ve been experimenting with different recipes.
I always liked caramel flavored deserts, so I decided to see if I could get the same effect with allulose.
The experiment was successful The allulose browned & caramelized just like sugar. By adding butter and salt, I got a pretty good approximation of salted caramel. I tried it mixed in with toasted walnuts and pecans. The sweet/savory and soft/crunch contrast was fantastic. I personally preferred the walnuts, but you could put it over whatever you’d like.
I also tried just pouring the caramel into molds and topping with flaky sea salt. Quite good, but I prefer it over the nuts.
Over medium heat, allulose melted, then caramelized, just like sugar.Plain salted caramel with flaky sea salt
I’ve included the recipe below if you want to try them yourself.
Toast nuts in a skillet over medium heat until fragrant. Set aside.
Add allulose and stir with a wooden spoon or heat resistant spatula. The allulose will clump up, melt, foam, and then brown to form a thick, amber liquid.
Add the butter, stirring continuously until it’s completely melted. Then slowly drizzle in heavy cream. Note: the mixture will bubble vigorously.
Stir in salt, then add the nuts and mix until combined.
Transfer to a bowl to cool and serve!
Notes
3.8g net carbs/serving
Nutrition information calculated by adding up macros of the individual ingredients and using walnuts for the nuts. Allulose not included in total or net carbs.
