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.
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.
Reader requests was really interesting. In every category, there was a Reader Request that either had a much lower BG impact than what I had found or gave significant insight into the BG impact of different ingredients.
I’m really excited about the vinegar/acid study, as well. There are three people participating so far, /u/genetastic, /u/kabong, myself. This should give us much more generalizable results and a decent shot of unraveling what’s going on with regard to effect size, scope, and mechanism (unclear from the literature). More collaborators would make the study even stronger, though, so if you’re interested, let me know.
Experiments this week focused the initial replication effort for the vinegar study and the last couple reader requests. Next week, I’ll shift back to the chocolate tests, though alternating those with the vinegar experiment will push back the final report on chocolate for a couple weeks (though I’ll have interim reports on the vinegar work).
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.
This week in my low-carb food study, I have Reader Requests!
For the past 6 weeks, I’ve been posting a series of studies on the blood glucose impact of low-carb foods (tortillas, cereal, ice-cream, bread). In the comments for each of these posts, I’ve been getting some great recommendations for other foods to try, so I decided to do a “Reader Requests” study where I measured the BG impact of the recommended foods.
The results were really interesting. In every category, there was a Reader Request that either had a much lower BG impact than what I had found or gave significant insight into the BG impact of different ingredients.
Here’s what I found:
Summary
Tortillas
The regular flour tortillas were much lower impact than I expected (30% peak BG & 70% iAuC vs. glucose), similar to that of the resistant wheat starch tortillas. This makes the resistant starch tortillas look even worse than I originally thought. Definitely never going to eat those again.
Neither of the recommended low-carb tortillas (Mr. Tortilla & A La Madre) beat out La Tortilla Factory for taste, texture, and BG impact, so I’m going to stick with La Tortilla Factory for personal meals.
Ice Cream
All three of the requested low-carb brands had lower BG impact than any of the brands I’d previously tested. The Two Spoons brand, in particular, was extremely good and has the only fruit-flavored low-carb ice cream I’ve seen. The Two Spoons Strawberry and Brownie Fudge flavors are my new favorite by a pretty wide margin.
Breads
The Julian Bakery breads were very low carb, but didn’t taste much like regular bread. They were interesting, but if I’m looking for a bread replacement, I’d pick something else.
Yogurt
Two Good Strawberry Yogurt had good texture and low BG impact, but the flavor was too mild and had a stevia aftertaste I didn’t like.
I would prefer to eat their plain yogurt and add my own mix-ins, maybe some nuts or chopped chocolate for a dessert.
Note: Readers also recommended several of the best breads that were included in the original bread post, including: Carb0naut (Can’t find the original request, sorry), Unbun Unbread (u/fawkesandholly, u/Impressive_Citron_84), Kiss My Keto (u/justjules83), and Base Culture (u/Spell_Chick).
If there’s anything else you want to see me test, please let me know in the comments.
– QD
Details
Tortillas
Tortillas tested. New requests in orange.Blood glucose impact of tortillas.
Summary: Nothing spectacular here, but the Mr. Tortilla could be good if you prefer smaller size tortillas/soft tacos.
La Tortilla Factory Flour Tortilla (not low-carb, as a control) (Can’t find the original request, sorry)
Much lower impact than I expected (30% peak BG & 70% iAuC vs. glucose), similar to that of the resistant wheat starch tortillas. This makes the resistant starch tortillas look even worse than I originally thought. Definitely never going to eat those again.
About the same BG impact as the regular flour tortillas (23% peak BG & 63% iAuC vs. glucose). Not great and not consistent with the claimed net carbs.
Taste was only ok, too. Will not use again.
Mr. Tortilla 1 Net Carb Tortilla (Can’t find the original request, sorry)
About the same BG impact as the best-in-class La Tortilla Factory tortillas (14% peak BG & 40% iAuC vs. glucose, or about half the LTF flour tortillas)
I didn’t like the taste as much as the LTF low-carb tortillas (bit too gritty), but they’re taco sized, which is very convenient for some recipes.
All-in-all, I found these to be ok, but will continue to buying the La Tortilla Factory low-carb tortillas going forward
Ice Cream
Ice cream tested. New requests in orange.Blood glucose impact of ice cream per gram.Blood glucose impact of ice cream per gram, zoomed in to only show low-carb ice creams.Blood glucose impact of ice cream per cup, zoomed in to only show low-carb ice creams.
Summary: All three of the requested low-carb brands had lower BG impact than any of the brands I’d previously tested. The Two Spoons brand, in particular, was extremely good and has the only fruit-flavored low-carb ice cream I’ve seen. The Two Spoons Strawberry and Brownie Fudge flavors are my new favorite by a pretty wide margin.
Talenti Double Dark Chocolate (not low-carb, as a control) (Can’t find the original request, sorry)
BG impact was consistent with the carb count (peak BG 27% of glucose, total carbs 31% of mass), and way higher than any of the keto brands. Not surprising.
Lower BG impact than any of the original brands I tested (2.0% peak BG & 5.5% iAuC vs. glucose)
Much harder texture out of the freezer than heavy cream-based ice cream. Even after sitting out for 35 min., I had to microwave it to get to my desired softness.
Had a strong chocolate and coconut taste. A lot lighter/airy than the heavy cream based brands, but still had a “creamy” texture.
Overall, I didn’t like it as much as the other brands, but I could see some people preferring it.
Lower BG impact than any of the original brands I tested (2.5% peak BG & 5.9% iAuC vs. glucose)
Softest texture of any of the brands. This and Two Spoons were the only keto ice creams that could be “scooped” straight from the freezer.
The Coffee Karamell flavor is more mild than I’d like, but it’s ok. I’d really like to try some of their other flavors, but this is the only one in my grocery that’s low-carb.
Way lower calories than other brands (240 kcal/pint vs. 470-680 kcal for other brands). Not sure why, though maybe it’s got a higher water content with more stabilizers & emulsifiers to soften.
Warning: The nutrition label on their website doesn’t match with what I found in the store. The BG impact matches up with the label, so if you’re buying this, make sure you read the label carefully.
The lowest BG impact of any ice cream I’ve tested:
Chocolate: 1.8% peak BG & 4.2% iAuC vs. glucose
Strawberry: 2.0% peak BG & 4.9% iAuC vs. glucose
This has the most similar texture to regular ice cream of all the brands I’ve tried. Scoopable, but a bit hard straight from the freezer. 1 min. in the microwave at 30% power got it to my preferred texture.
The chocolate flavor was good, though I’d prefer a stronger flavor.
The strawberry was amazing. Extremely smooth, creamy taste and the strawberry mix-ins taste like firm strawberry jam. This is the only keto fruit flavored ice cream I’ve found. I’ve always preferred fruit-flavored ice-creams and this was a great example.
I also tried their Brownie Fudge & Coffee Toffee flavors, but didn’t do a BG test
Brownie fudge: My second favorite after strawberry. A stronger chocolate flavor than chocolate and the brownies gave a nice flavor and textural contrast (even stronger chocolate flavor & soft chewy texture).
Coffee Toffee: Very strong coffee flavor with a great texture contrast from chocolate chips and toffee. If you like coffee ice cream, I’d definitely recommend it.
Breads
Bread tested. New requests in orange.Blood glucose impact of bread.
Summary: The Julian Bakery breads were very low carb, but didn’t taste much like regular bread. They were interesting, but if I’m looking for a bread replacement, I’d pick something else.
Julian Bakery KetoThin Bread (Can’t find the original request, sorry)
The lowest BG impact of any of the breads I’ve tested (3% peak BG & 8% iAuC vs. glucose)
This one was a bit odd. It was soft, moist, and tasted pretty good, but not at all like bread. You can really taste the cream cheese in it.
When toasted or fried, it became slightly crispy and the cream cheese taste was much less noticeable.
Julian Bakery PaleoThin Sandwich Bread (Can’t find the original request, sorry)
3rd lowest BG impact, after Julian Bakery KetoThin & UnBun UnBread (6% peak BG & 10% iAuC vs. glucose)
The bread was a little wet when I opened it and tasted slightly sour. Taste was not that great, though maybe it was starting to spoil? I ate it right after opening the sealed package and 3 days after it arrived, so if it was spoiled, that’s not a good sign.
Yogurt
Blood glucose impact of Two Good Strawberry Yogurt.
Low BG impact (4% peak BG & 7% iAuC vs. glucose), a little higher than its net carb count (2% of mass)
Strawberry flavor is very mild and has a stevia aftertaste that I don’t like.
Texture is great, creamy and not chalky like some greek yogurts
I didn’t like this and would prefer to eat their plain yogurt and add my own mix-ins, maybe some nuts or chopped chocolate for a dessert.
Design/Methods
Foods. Full nutrient and ingredient info here. Key nutrition facts in the tables in above.
Procedure. At 5:00a, I took 4.5u of Novolog (fast acting insulin, duration of 2-4h), then drank a Ketochow shake (website, BG testing) at 5:30a. After that, no food or calorie-containing drinks were consumed and no exercise was performed. Non-calorie-containing drinks were consumed as desired (water or caffeine-free tea). At 10:30am-12 pm, the substance to be tested was eaten as rapidly as comfortable and notes on taste and texture were recorded (before observing any change in blood sugar).
Blood sugar was monitored for 5h using a Dexcom G6. Calibration was performed 15-30 min. before the start of each experiment.
Separately, all breads were toasted using a Brava oven (wheat toast, setting 7). Taste and texture were recorded.
Data Processing & Visualization. iAUC was calculated using the trapezoid method (see data spreadsheet for details). Data was visualized using Tableau.
Medication. During these experiments, I took long-acting basal insulin each evening at 9pm (Lantus, 1.5u) and 2000 mg of metformin and multivitamin each morning at 5am. I did not dose for the experimental food ingested.
