Of the previous studies I’ve done, the most informative and useful for me was measuring the effect of different macronutrients and low-carb ingredients.
I was especially fascinated, and disturbed, by the huge variation in blood glucose impact of fibers that are listed identically on nutrition labels. This makes me extremely suspicious of the so-called “net carb” count listed on most low-carb food. I suspect that there’s a wide variation in actual blood glucose impact for foods with similar nutrition labels.
To follow up on that, I’m going to test the effects of popular dietary supplements and low-carb foods to see if claims about them really hold up. For low-carb foods, I’m going to focus on the ones that I like or that are recommended by commenters here or on Reddit. For supplements, to avoid wasting a lot of time chasing after BS fads, I’m going to focus on those that are either reasonably supported in the academic literature or otherwise appear to have solid data backing them up.
Lastly, it’s widely believed that the relative blood sugar impact of foods varies from person-to-person. If you’re interested in helping me to quantify that, let me know in the comments or send a via the contact form or to quantifieddiabetes_at_gmail.com.
Testing Queue:
- Baseline:
- Glucose re-test:
- Low-carb foods:
- Ketochow: Reported
- Carbquick: Complete
- Tortilla: Complete
- Bread: In progress
- Snack bars: In queue
- Ice cream: In queue
- Supplements:
- Vinegar: In queue
- MSG: Reported
Week 1: Tortillas
Since this is going to be an on-going exploration, rather than wait for complete sets of data (which could take a long time), I’m going to post each weeks worth of data as I collect it in the hopes of soliciting feedback to guide later experiments.
As always, if you have any comments, suggestions, ideas for new experiments, or want to participate, please let me know in the comments or send a PM via the contact form or to quantifieddiabetes_at_gmail.com.
Ingredient Background
When I went to the supermarket recently, I noticed that they’ve started carrying low-carb tortillas. The macros looked decent (2-5g net carbs/tortilla depending on brand & type), so I wanted to give them a try.
Procedure
At lunchtime (11a-12p), I consumed the specified quantity of food. No other food, drink, or medication was consumed except for water (ad libitum, but always less than 500 mL). Note: I take a long-acting basal insulin (lantus, 2u/day).
Blood sugar was monitored for 5h using a Dexcom G6. Calibration was performed 15-30 min. before the start of each experiment.
Results
As shown in Figure 1, all of the low-carb tortillas show a steep rise for the first 1-1.5h, similar to glucose, followed by a leveling off with a peak 2-3h after eating. This profile is similar to resistant wheat starch, their main ingredient (listed as “modified wheat starch”, but same thing).
Most interesting is the difference between brands. La Tortilla Factory tortillas have about half the effect of Mission and Nutri-Rica tortillas (~13 vs. 25% of glucose for peak BG/g & ~30 vs. 60% of glucose for iAuC). They are thinner and have a, to me, better taste and texture as well, so a significant overall win.
From looking at the ingredient list, the main difference seems to be that La Tortilla Factory uses cellulose fiber instead of Resistant Wheat Starch. I haven’t tested cellulose fiber, but Resistant Wheat Starch has a significant impact on my blood sugar, so that’s presumably where the difference is coming from. I’ll get and test some cellulose fiber to confirm.
Interim Thoughts and Next Steps
From this preliminary data, it looks like there are meaningful brand differences for similar products with similar net carbs, justifying these experiments.
I looked for other low-carb tortillas that don’t use resistant wheat starch, but except for La Tortilla Factory, they all are either too high carb or high calorie (e.g. using almond flour) and I’d rather leave room for more fillings.
Does anyone know any other good low-carb tortillas I should try?
Next, I’m going to do a more detailed analysis of the tortilla results while starting testing on breads, ice creams, and snack bars.
As always, please let me know if you have any thoughts or suggestions.
– QD
Nutrition & Ingredient Information
La Tortilla Factory – Flour
La Tortilla Factory – Wheat
Mission – Wheat
Mission – Spinach
Mission – Tomato
Nutri-Rica
