Do artificial sweeteners affect blood sugar?

Last week, I started an experiment to better understand how different foods and lifestyle choices impact blood sugar, using a constant-glucose-monitoring device.

Today, I’m sharing the results of the first experiment: Do artificial sweeteners affect my blood sugar levels?

While the answer may seem obvious – artificial sweeteners contain no sugar – some people still believe there may be an effect. For example, artificial sweeteners could potentially under some circumstances affect insulin levels, indirectly affecting blood sugar and ketone levels.

Planning the experiment

We designed the following experiment:

I would drink a 17 oz (0.5 liters) sugar-free, artificially-sweetened, beverage in 15 minutes. Then, for the next two hours, I would observe my blood-sugar levels using the Dexcom G5 mobile app.

To increase the reliability of the experiment, I made sure of four things:

1. That the soda I drank would be caffeine free.
2. That I didn’t eat or drink anything, nor do any form of exercise, 2 hours prior to and after drinking the soda.
3. That my blood sugar was relatively stable for at least 30 minutes before drinking the soda.
4. That I would do the same test at least twice.

The experiment could start.

Drinking Sprite Zero

Sprite Zero was my drink of choice for a few reasons: I drank it sometimes in my pre-low-carb days, it’s sugar and caffeine-free drink, and it contains artificial sweeteners (aspartame and acesulfame potassium). Perfect.

I put the bottle to my mouth and took a big sip.

“Yuck, way too sweet!”, I told my wife. But a few sips later, I was enjoying the drink.

After fifteen minutes the bottle was empty. My eyes were glued to the app. What would happen to my blood sugar?

That’s when it happened…

…or didn’t happen I should say

Blood glucose

Nothing.

For the full two hours (from around 08:30 am to 10:30 am) my blood sugar stayed pretty much the same – it was hard to notice that I’d consumed anything. When I re-did the experiment a few days later I got similar results.

Sprite Zero does not affect my blood sugar

This short self-experiment indicates that Sprite Zero – containing the artificial sweeteners aspartame, and acesulfame potassium – does not noticeably raise nor lower my blood-sugar levels.

My guess is that most people would get similar results, although this n=1 experiment can of course not prove this.

Though our experience and this self-experiment indicate otherwise, it’s certainly possible that different people would respond differently to drinking Sprite Zero. For your reference, I am a 36-year old insulin-sensitive male, weigh 152 pounds, exercise for 10-15 minutes five times a week, with no history of obesity or diabetes.

Note that in a 2012 experiment we did, a similar drink (Pepsi Max) did not affect blood-sugar levels either, but there was a surprising effect on ketone levels.

Regardless of the effects artificial sweeteners have on blood sugar, we recommend that you do not consume them. Artifical sweeteners are problematic for a number of reasons – they have for example been shown to potentially increase appetite and maintain cravings for sweet foods.

What do you want us to test next?

Feel free to let us know in the comments below.

Earlier tests

Are you interested in my earlier tests? Check out this earlier series of 3 posts:

  1. Why You’re Not in Ketosis
  2. How Much Protein Can You Eat in Ketosis?
  3. What to Eat in Ketosis

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109 Comments

Top Comments

  1. Sofi
    Test Stevia and Xylitol!
    Reply: #26
    Read more →
  2. Kim P
    I want to know if your ketones were affected as they were in 2012. For sure test stevia and xylitol for blood glucose and ketones.
    Read more →
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All Comments

  1. Adam
    Can we test the effect on stomach flori?
  2. Julia
    LSee did it with Zero Coke.
    The video is here:
    https://www.youtube.com/watch?v=mWiPz8Z_Lk8
  3. Dneis
    Test Swerve, please. (It is in some recipes for Maria Emmerich's Keto book so I think it needs to be tested).
  4. Grannie Vee
    There is a difference between glucose rising and insulin rising. You can't measure raised insulin levels with your glucose meter. Raised insulin caused by carbs and sugars will stop your weight loss. This just proves that it didn't spike his glucose and nothing else.
  5. Rachel
    Xylitol please
  6. Anna-Marie Robertson
    How about cinnamon?
  7. Gaubizi
    Nicely written, but frankly I don't get why a drink that does not even contain sugar should spike glucose levels. Wouldn't it be smarter to test insulin levels? This also seems to be suggested when looking at the results of the Pepsi Max test. Insulin, not glucose levels, is the culprit.

    PS: Is there a similar app that tracks insulin levels?

  8. Diana
    What about insulin levels! If you're insulin resistant (Diabetes Type II) and it triggers insulin production, (the invisible elephant in the room); then it's not ok.
  9. Jon
    Check out ketoconnect.net. They did a video testing all the sweeteners. It’s on YouTube.
  10. Lee
    How about testing the effects on liver enzymes.
  11. Nancy
    But they do give the brain a message that X calories are on the way, and when they don’t appear, cravings increase. Plus, why keep the sweet taste activated? As long as I drank diet sodas, used artificial sweetners I kept wanting sweet things. Now, I just don’t care about them.
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