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

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