I’m always looking for collaborators for future experiments. If you’re interested in collaborating on scientifically rigorous self-experiments with low-carb foods, supplements, or other health interventions, please let me know in the comments or via the contact form on the right.
I posted the results for low-carb chocolates this week. Found quite a few good ones, most notably the high cocoa stone ground chocolate from Taza and allulose-sweetened dark chocolate from Trendz. On the scientific side, I got even more evidence that there’s a large variation in the impact of different fibers, even ones with the same name listed on the nutrition label. I’m going to see whether I can source a decent variety to test.
Experiments this week focused on the last chocolates and samples of a low-carb chip under development by a food start-up (details and review to be provided when I’m allowed to post). Next week will focus on collecting more data for the vinegar study and starting to look at flour replacements and high-fiber fruits and vegetables.
Active & Planned Experiments
Blood Glucose Impact of Low-Carb Foods & Ingredients
Goal: Determine blood glucose impact of low-carb foods and ingredients
This week: 4 commenter requests (Two Good yogurt, Julian Bakery bread, and “control” tortillas & ice cream (non-low carb, for comparison)) and 3 chocolates.
Since I’ve started posting these food-effect studies, one of the most requested products has been low-carb chocolate. As with other low-carb products, a ton of new low-carb chocolates have become available. Initially, most used a simple substitution of a non-nutritive sweetener, like erythritol, for sugar. However, I’ve noticed in the last few years, a number of high cocoa/low sugar chocolates that use regular sugar, just in very low quantities (90-100% cocoa).
In both cases, the net carb count can be very low, though this largely relies on subtracting the high fiber content of the cocoa. Since I’ve had very mixed results with the blood glucose impact of dietary fiber (see here & here), I tested them myself.
Towards that end, I tested 13 chocolates from 4 different categories (grouped by sweetener). Here’s my overall conclusions:
Lowest BG impact: Lily’s Almond Dark & The Good Chocolate Signature Dark
~65% of the impact of 100% cocoa bars
Best combination of taste & impact: Taza Wicked Dark & Trendz Bar
Chocolate with added fiber shows much higher blood glucose impact
There’s a significant variation between brands
This could be due to different fiber type or quantity
Watch out for the ChocZero chocolate, which gave ~2x the BG impact of the next highest chocolate.
Evidence continues to pile up that there’s a large variation in the impact of different fibers, even ones with the same name listed on the nutrition label. I’m going to see whether I can source a decent variety to test.
If anyone knows where to get the fibers and resistant starches that are used in low-carb prepared foods (especially from the actual manufacturers), please let me know in the comments or by PM.
As always, please let me know if you have any thoughts, suggestions, or anything else you’d like to see me test.
I’m always looking for collaborators for future experiments. If you’re interested in collaborating on scientifically rigorous self-experiments with low-carb foods, supplements, or other health interventions, please let me know in the comments or via the contact form on the right.
Experiments this week focused on finishing up the low-carb chocolate tests and starting the next stage of the vinegar study (determining how dose, dilution, timing, and macros influence the effect). For the chocolates, I’ve only got a few samples left, so I should be able to finish out the study this week. For vinegar, thanks to /u/genetastic, we’ve got the analysis of the initial tests done and I just need to write it up. Might get it out during the week, but definitely by next weekend. With the better analysis by /u/genetastic, we’re seeing a statistically significant effect, so should be interesting. More collaborators would improve the study considerably, so if you’re interested, let me know.
Active & Planned Experiments
Blood Glucose Impact of Low-Carb Foods
Goal: Determine blood glucose impact of low-carb foods and ingredients
This week: 4 commenter requests (Two Good yogurt, Julian Bakery bread, and “control” tortillas & ice cream (non-low carb, for comparison)) and 3 chocolates.
I got my COVID vaccine booster last week. As with my previous two COVID vaccines, I got the standard side-effects:
Soreness at the injection site
Fatigue
Headache
Muscle soreness
Fever
Chills
High blood sugar
These started about 5h after getting the vaccine and lasted ~24h, the same as the last two times.
In addition to the standard effects, when I woke up the day after getting the vaccine, I noticed that my heart rate was 100 bpm, 21 bpm higher than average and way outside my normal range (see Figure 1).
Figure 1. Pulse upon arising over the last 4 months, measured by Omron blood pressure monitor. Reference lines & bands were calculated for data prior to the vaccine.
Intrigued by this, I decided to track by pulse over the course of the day using my Omron blood pressure monitor. My original intention was to measure every hour, but I skipped several measurements where either my arm was sore at the measurement site or where I fell asleep. I had also wanted to track my temperature, as that’s known to correlate with increased heart rate1, but my family had taken our thermometer for the day.
As can be seen in Figure 2, my pulse peaked shortly after waking up, then declined steadily throughout the day, ultimately returning to about normal by the next morning. This corresponded to my subjective assessment of how I was feeling. I felt the worst when I woke up, got steadily better over the course of the morning with an abrupt improvement when I took a nap around 2pm (waking at ~4p), and felt completely fine when I woke up the next day.
Figure 2. Pulse vs. time the day after receiving vaccine, measured by Omron blood pressure monitor.
Although vaccine side effects have been widely reported, I couldn’t find much on the effect on heart rate. The only paper I found was a medRxiv paper from Quer et. al. at Scripps, which reported a small but statistically significant increase of 1.5 bpm after the second dose of the Pfizer or Moderna vaccine for a population of 3,300, with heart rate peaking on the day after vaccination and returning to normal by day 6. This is a much smaller effect size and longer duration than I saw, but there are some critical differences:
They’re averaging a large number of people and there may be significant person-to-person variation in the effect.
They report average the heart rate over the course of the day, while I report individual time points.
They used data from Fitbit or Apple Watch vs. a blood pressure monitor.
To check the last two factors, I plotted the heart rate data from my Apple Watch (see Figures 3 & 4). Unfortunately, the watch had not recorded my data for 4 out of the 5 days prior to my vaccination (no idea why), though there was nothing unusual in my routine those days.
As can be seen from the graphs, the day after getting the booster vaccine, my arising and awake pulse were 27 and 13 bpm higher than average, respectively. This is consistent with the 21 bpm rise observed with the Omron and much higher than that observed by Quer et. al.. However, using the watch data, I do see the longer recovery time (~6 days) reported by Quer et. al. Not sure why I didn’t see this with the Omron, but it could be related to the fact that I don’t use it as often, resulting in a higher uncertainty in the average value.
Figure 3. Pulse upon arising over the last 4 months, measured by Apple Watch. Reference lines & bands were calculated for data prior to the vaccine.Figure 4. Pulse while awake over the last 4 months, measured by Apple Watch. Reference lines & bands were calculated for data prior to the vaccine.
This strongly suggests I’m actually seeing a larger effect and the result of different measurement methods. Anecdotally, I had worse side effects from the vaccine than most people I’ve spoken with, which is consistent with the larger increase in heart rate.
Have any of you seen an increase in heart rate from the COVID vaccine? If so, let me know in the comments.
I’m always looking for collaborators for future experiments. If you’re interested in collaborating on scientifically rigorous self-experiments with low-carb foods, supplements, or other health interventions, please let me know in the comments or via the contact form on the right.
After two experiment posts last week, I didn’t have enough data for any this week.
Experiments this week focused the initial replication effort for the vinegar study and testing of low-carb chocolates. /u/genetastic, /u/kabong, I have the data for the initial vinegar tests and are in the process of analyzing the data. Preliminary report will post next weekend. As a quick preview, we’re seeing signs of an effect, but the data is too noisy to be certain. More collaborators would improve the study considerably, so if you’re interested, let me know.
In terms of personal data, this was a weird week. I had a several days where I overate and/or mis-estimated my insulin dose at dinner, leading to out-of-range blood sugars and insomnia. I also got my COVID booster on Saturday, which led to the standard side effects, including fever, high blood sugars, and pulse. All-in-all, I pretty much need to ignore all overnight data from this week.
Active & Planned Experiments
Blood Glucose Impact of Low-Carb Foods
Goal: Determine blood glucose impact of low-carb foods and ingredients
This week: 4 commenter requests (Two Good yogurt, Julian Bakery bread, and “control” tortillas & ice cream (non-low carb, for comparison)) and 3 chocolates.
