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


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

Advanced low-carb topics

Popular now

Low-carb basics

Q&A videos


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 →
1 2 3

All comments

  1. Adam
    Can we test the effect on stomach flori?
  2. Julia
    LSee did it with Zero Coke.
    The video is here:
  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.
    Reply: #113
  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 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.
  12. Greg
    I'm curious about Powerade Zero
  13. Neil
    Agreed! Not enough people are talking about foods that raise insulin levels, which is the direct cause of weight gain. I'm sick and tired of the calorie counting movement.
  14. Anne
    Please test stevia- Zevia beverages and swerve
  15. Liza J. Kiesling
    I also am wondering if there is an insulin response to sweeteners even if glucose appears normal stopping weight loss. I also wonder if heavy whipping cream could raise insulin as well.
    Reply: #116
  16. Kristin Parker Team Diet Doctor
    Yes, this is entirely possible. We do recommend avoiding sweetened beverages for this reason. Also yes, dairy is highly insulinogenic.
  17. Robyn
    What about the fat bombs that taste like a Reece Cup?
    Reply: #118
  18. Kristin Parker Team Diet Doctor

    What about the fat bombs that taste like a Reece Cup?

    That would depend on the recipe, the carb count and the sweeteners used.

  19. Vichet
    Test powerade zero and propel water
    I have been using whey protein powder with artificial sweeteners for last six months, before taking whey protein 6months ago my blood glucose was normal,now's it have increased inspire of doing weight training regularly
  21. JR
    Everyone says the sweeteners raise insulin. If this were true, then why didn't his blood sugar go down? On a continuous blood glucose monitor you can see the moment when insulin raises because blood sugar drops severely. If I drink a diet Coke while fasting, there is zero effect on my blood sugar which makes it highly unlikely that I'm having an insulin response. The science on the insulin response of diet sweeteners is very shoddy at best.
1 2 3

Leave a reply

Reply to comment #0 by

Older posts