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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  1. Margo
    If you cannot spell dummy, and misuse the word effect (not a verb, dummy), you should not call people dumb ass. Your. Diabetic. You 're. He never said he was doing actual deep science.

    Hey dumy it may not effect your BS ,it will effect yor brain chemistry to consume more carbs. If your really diebitc your one dum ass.

  2. Wayne
    What about a drink with caffeine such as diet Mt. Dew?
  3. Jim
    Test Splenda zero
  4. Ed
    I would be curious to know what the combination of low carbs and diet soda would produce.
    How a Zero sugar will interact in the presence of Carbs
    ( Cole slaw salad with soft drink)
  5. jim
    Serum glucose levels did not change but did insulin levels rise?
  6. biggus
    I think saying aspartame is linked to and then saying 'look it up', is like saying 'fat will make you fat, just look it up.' Delaney clause, dogma, and big bucks can make us believe things that may not be true. Of all the people in the world, LCHFers should be aware of such things.
  7. biggus
    Why does Xylitol kill dogs and not people? Because they are dogs, and we are people, and while we have much in common, we aren't the same thing. If you think this is a silly comment... well, why does chocolate kill dogs? Is there something sinister about that? No. Forget dogs, we aren't dogs, or mice, or rats.
  8. Kay
    Thank you for doing this test! I suggest repeating the test with erythritol/stevia-sweetened pop. In my area, Zevia is the most common brand.
  9. Jafar Khayati
    Fruktose !
  10. Jeff
    Coke Zero would be of interest to me.......thanks for the Sprite Zero test results!
    Reply: #102
  11. Eric
    Leaving out ketone measurement is bluntly BS! This is not value add for our ketogenic lifestyle. Why did you do this? Please repeat these N=1 and measure both BHB and BG. Do it right or don't do it at all! ?
  12. Michelle
    I have severe Hypoglycemia and now wear a Dexcom GCM. Before getting my GCM I didn't know what was triggering my low blood sugar every morning. I watched my carbs and only used sugar free products. So when I started using my CGM I found out that the Splenda in my coffee was the problem. I have since changed to Stevia and a Keto diet keeping my carbs 20grams and under and can happily say I haven't passed out and have been seizure free for several months!
  13. Sherry
    My sweetener is Sweet N Low. I am diabetic but don't like any other sweeteners. Please tell me if this one is ok. I usually drink 3 glasses of decaff tea a day and use my sweetners. Thank you.
    Reply: #86
  14. Mary
    I would be interested in results for Propel Zero (sweetened with Acesulfame Potassium and sucralose). Thanks!
  15. Carolyn
    1. Erythritol
    2. Monks Fruit

    Thanks for testing!

  16. michael pollard
    Not surprised about blood sugar results. What I'd really like to know is what insulin, if any, response there was.
  17. Laura
    I would be interested in seeing how stevia (preferably powder form) affects insulin. Thanks!
  18. Luke H
    These posts are going to be fascinating to follow - what a good idea! I'd love to see foods tested with and without PGX to see if the blood sugar spike is blunted when taken alongside that supplement. Mark Hyman recommends it highly for that purpose and I think it'd be very interesting to see the results.
  19. Laura
    I realize this is anecdotal, but I have been drinking artificially sweetened soda for years and have NEVER noticed any increase in appetite or cravings for sweet foods because of them. Thank you for doing your test and reporting the results so honestly. I am glad to know that these drinks do not appear to affect blood sugar levels.
  20. Alan Harris
    I'd like to know if artificial sweeteners pose health risks not associated with diabetes.
  21. Landen
    Pepsi Max and Sprite zero have the same sweetener, I'd like to know why one affected the keytone levels and one didn't. Perhaps the culprit in the Pepsi max ketone drop wasn't the sweetner then?
  22. Louise Mills
    Experiments/studies with glucose and ketone results after ingesting the following would be exciting to have:

    Erythritol, Xylitol, Maltitol, Mannitol, Sorbitol, (Splenda), Saccharin (SugarTwin, Sweet'N Low), Advantame, Acesulfame potassium (Sunett, Sweet One), Stevia extracts (Pure Via, Truvia), Aspartame (Equal, NutraSweet), Hydrogenated starch hydrolysate, Tagatose (Naturlose), Neotame, Isomalt, Trehalose, Lactitol, Sucralose

    This is a lot! However, you would be creating a new database of much needed information! Maybe you could start by testing just one of these a month? Could you enlist the help of members online?

  23. Peter
    Nice work, this is what I would expect from other tests I have seen: Aspartame is made from amino acid mix, and should not affect your endocrine (insulin) system. I have seen similar laboratory results for Splenda (Sucralose) which also has zero affect on insulin levels. I have seen results both ways for Stevia, some tests found it has no affect, others the opposite.

    It would be interesting to see if you can confirm the effects of Splenda and Stevia.

    Saccharin was found to have stimulated insulin response more than sugar, which would be very bad for diabetics, and insulin resistant individuals. Stay away from Saccharin!

  24. Monique
    I would be very curious if you could do the same experiment with sucralose (Splenda) and Stevia. Again - something that has zero sugar added to it. I'm definitely curious like some others above... While I don't want to make a habit of sweeteners, I do find them helpful sometimes so that I don't feel "deprived".
  25. Judy DeLibera
    I would like to see the affects of any artificial sweeteners on insulin levels as insulin is the direct link to obesity. We know from the insulin index that just because your blood sugar increases, does not necessarily correlate one for one with insulin. I'd love to see a broader Insulin index. Do you know if anyone is working on that?
  26. Lauren
    can you test water intake to see how it affects blood sugar levels?
  27. Lucy Akpabio
    What's your take on splenda. I use that a lot.
  28. anne
    Importantly, I wonder if you see an impact from packaged aspartame bc of the binders like maltodextrin. I can't do d any info about how much is in a packet, which seems critical a person uses a large number of packets per day. I'm also curious to see if the result of the diet soda experiment differs in an insulin resistant person
    Reply: #95
  29. Chad
    I’d like to see DEXA scan done prior to then after a prolonged/multi day water fast to see how much weight loss is in fact lean tissue compared to fat loss with a non diabetic fat adapted person. Perhaps the after measurements should be done a couple of days after moderate carb intake to replenish muscle glycogen to improve the accuracy of the test.
  30. Lorrie
    I'd like to see an experiment with dairy products & the effect it may or may not have on weight loss.
  31. Amy G
  32. Fausto
    Stevia please.
  33. Dom
    Not all artificial sweeteners are the same.
  34. Frank
    Stevia and xylitol please. Surprised that Diet Doctor doesn't provide advice on this - as many diabetics use as an alternative.
    Reply: #88
  35. 1 comment removed
  36. TeeDee
    Hi Sherry; I'm just wondering if you still have any cravings for carbs/sugar. Some strongly believe that having the artificial sweeteners keeps our taste buds craving more carbs like fruit, baked goods or other sugary foods. Thanks for any insights :)
  37. Max Rockwell
    Fantastic Post

    Prepare to be shocked I drink a 2 liter of Diet Pepsi almost everyother day eat a low carb high fat diet and lost well over 100 lbs doing it. Do you and don't worry about the small stuff

    Check out my new ebook

    Keto Diet Bestseller

    Out now on amazon

  38. TeeDee
    Maybe we should remember that diabetics also tend to have their own glucose monitors and can easily check out how they are affected by those sweeteners themselves. Diet Doctor gives all the basic low carb info for free, even though they're under no obligation to. Perhaps we shouldn't be expecting them to do anything extra and show a little gratitude instead :) I for one, really appreciate that they did this n=1 experiment and shared the results..

    Stevia and xylitol please. Surprised that Diet Doctor doesn't provide advice on this - as many diabetics use as an alternative.

  39. Howard
    No controls?? Suggest sprite with sugar and/or HFCS, and distilled water.
    My husband had a liver transplant, this automatically became a type 2 diabetic. Even with a great diet and exercise we struggled to keep his bs below 300, even with increasing both short and long acting insulins he injects. He drank a lot of sugar free flavored water and stevia in coffee. When he cut those out, and only those, his sugars dropped.
    It changes the bacteria in your digestion, from our understanding.
  41. Cindy C
  42. Jo
    You need to do the experiment on a diabetic! Type 1 - then you can actually say it doesn't affect blood sugar! You produce insulin it will compensate- I love your website the food and recipes and info, very good, but you can't go around saying it doesn't affect blood sugar when you test on non diabetics, and type 2 still produce insulin. Diabetics start eating stuff and it wrecks their bodies! Just like all the info on GI index/ never tested on type 1 diabetic! So they don't have a clue what affect those foods actually have on blood sugar! Find a type 1 to test it in and then you will get a fair idea of what you're testing for.
  43. Natasha
    please test Sukrin sugar as after eating it in baking or deserts my ketone strips are no longer red.
  44. Rich
    I'm curious about the effect or lack thereof of sugar alcohols on blood sugar and ketone levels.
  45. Kay
    anne, I buy sucralose drops so they I don't get the maltodextrin or dextrose in packages of sweetener. It's very convienent - I just keep one in my kitchen and one in my desk at work. You may also be able to find stevia or monk fruit packets where the bulking agent is erythritol. Just read the ingredients carefully!
  46. Helen
    I too, would like to know about Stevua. Can it be used with a keto diet?
  47. Ruth
    What effect do various sweeteners have on insulin? Erythritol, stevia, xylitol?
  48. Sid
    How difficult is the blood sugar transmitter to use or insert on your body?
    Is this something many of us could get and do our own testing/checking?
  49. Lance
    I'm not concerned with blood glucose levels - I'm concerned with the impact on insulin and ketone levels. Ace-K, Sucralose (Splenda), , dextrose, maltose, saccharine (Sweet'N Low), Stevia/Monk Fruit/Chicory Root bound to maltodextrin all knock me out of ketosis - which leads me to believe that it spikes my insulin - and actually causes my blood sugar to dip a little as a result as I am still very insulin sensitive (so blood glucose readings are worthless). The only "soda" drinks that keep me in ketosis are those using aspartame as the sweetener (currently: Diet Coke, Diet Dr. Pepper, Diet A&W Cream Soda, and Diet Mug Rootbeer). Of course, you can go to your favorite health food store and buy items like Zevia - but when on the go and I need something from a vending machine besides water, only the soft drinks using aspartame will keep me in full ketosis.
  50. Julia
    It’s a good idea to test that and by the way LSee did it too. We found the same results, so now it’s n=2 :)

    We also tested other food. Feel free to check our YouTube channel!

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