Another reason to be skeptical of artificial sweeteners

Bad for blood sugar?

Bad for your blood sugar?

According to exciting new research, several common artificial sweeteners may have a previously unknown side effect. They affect the gut flora and may thereby elevate blood sugar. Not only in mice, but also in humans.

Science Daily: Certain gut bacteria may induce metabolic changes following exposure to artificial sweeteners

Forbes: Could Artificial Sweeteners Be Contributing To The Obesity Crisis?

The study:

Nature: Artificial sweeteners induce glucose intolerance by altering the gut microbiota

This is of course a result that needs to be repeated in more and larger studies in order to learn more about its significance. But it’s already another reason to play it safe and use caution when it comes to artificial sweeteners. Personally, I almost never use them. This is truly a matter of habit. More than a decade ago I used to drink diet soda regularly. Now I never do and I don’t miss it one bit.

Do you use artificial sweeteners and if so, for what?


Previously on artificial sweeteners


  1. Victor
    Too much research out showing bad effects from drinking diet sodas. I gave up all artificial sweeteners one year ago and I no longer miss them.
  2. Natalie
    I only use pure Stevia drops, as Stevia doesn't raise blood sugar at all and may even lower it in some individuals:
  3. Jorge
    So, which is the lesser evil now, Diet or regular Coke?
  4. Roger
    According to Dr. Bernstein's call last night the study used powdered artificial sweeteners which have dextrose in them.
  5. Andrew Chalkley
    I drink Diet Coke regularly on LCHF and I'm losing weight still.

    I am ordering a blood glucose testing kit to experiment with it.

    Reply: #21
  6. Boundless
    The full paper is available via a link from Mark's Daily Apple.

    Having now read it, I don't think it can be dismissed with the usual skepticism regarding typical confounding that plagues most nutrition trials. Plus, it wasn't just mice - they did test people. And it appears they did use pure saccharin for some tests (and not just the commercial product, which is mostly a sugar). And they isolated the suspected effect via FMT (in the mice, anyway).

    I'm going to conjecture that they'd get very different results in a low-carb human cohort who are paying attention to the status of their gut biome. But for typical moderate to high-gly consumers, who think a can of Diet Croak cancels out the Krispy Kreme they're having with it, this paper is bad news that probably explains why their weight isn't budging.

    The AS products they tested (aspartame, sucralose and saccharin) are the most popular in processed foods. They are in general probably not the AS products most careful eaters consume.

    I've been avoiding aspartame since shortly after its introduction, and nothing would surprise me about risks from it. I've likewise avoided saccharin, for no particular reason. I do consume a trace amount of sucralose, present in some some Quest bars, and have considered it to be a minor biome hazard (which concern is consistent with what this paper reports).

    I don't drink sweetened beverages at all, sugar or "diet", for multiple reasons. So on the whole, this paper is just very interesting.

    However, my family uses recipes with stevia, erythritol, monk fruit and more rarely xylitol, and this paper signifies that testing these sweeteners specifically for glucose tolerance and biome effects would be quite worthwhile. I'm not even sure I have a guess at the outcome.

  7. Tim Rupe
    This is one thing I just don't get. How can you get elevated blood sugar (more sugar in your blood), if you're NOT EATING MORE SUGAR??? Does it just get created out of thin air? I think not.

    I've had great success with LCHF, all while chugging tons of diet soda, and using Splenda in my coffee. I can understand the idea that sweeteners have a psychological effect that stimulates eating, but not for mysterious and spontaneous blood sugar.

    Reply: #9
  8. Eric Anderson
    I Use to do stevia. Now I avoid all sweeteners.

    Why use fake when stopping real sugar?
    Once off the adiction the ability to dedect sweet taste improves.
    Cream has a sweet taste
    sometimes sugar is added to meat dishes or green vegetable dishes
    Being sugar and fake sugar free improves the ability to avoid these always lurking carbohydrate sources.


  9. Anne Robertson
    Tim, the liver can make glucose from protein. This process is known as gluconeogenesis.
  10. CNC
    I drink diet soda (a lot) and use a liquid Splenda product for my coffee or tea and for sweet desert recipes. I have not seen any affect on my ability to keep my weight down or any cravings. I lost 15 kg on a HFLC diet and have maintained the weight loss for 4 1/2 years so far. I think if you have a bit of a sweet tooth it is a lot better than sugar. If you can get by without any sweeteners even better.
  11. erdoke
    Soda is junk with or without sugar. I don't get it why anybody should drink any type of sodas.
    First one needs to liberate him/herself from the addiction to sugars and grains. This normally results in a significant decrease of cravings for sweet foods. At that stage I just said no and stayed away from all kinds of sugary stuff except for the occasional fruit. Which I tend to have more and more often with mascarpone cheese btw. :o))
    Just as Boundless I'd love to see a follow-up study including common naturally occurring polyols. Some of these seem to have an adverse effect by providing fermentation raw material to "good" bacteria.
    Reply: #24
  12. Suzanne
    @Tim, artificial sweeteners have also been shown to produce an insulin response.
  13. Justin
    I think some of this stuff is really playing into confirmation bias. The human "trial" only had results with saccharine. I read from a few different sources that the trials with the other, more common, artificial sweeteners didn't produce any meaningful results in humans, so they didn't really get reported on. I'm not saying that artificial sweeteners are 100% safe because of this, but I am saying that, if you're going to take a scientific approach to nutrition, you should probably apply that across the board. If a larger-scale RCT trial on one or more of the more common types of artificial sweeteners comes out, I'll be more than happy to believe that they actually are harmful.
  14. Toni
    I've eaten LCHF for 3 years and seen many benefits - weigh loss, weigh maintenance, perfect blood sugar control etc. I do have AS (mainly sucralose in pure, non-bulked form) and the occasional diet soda and I'm not convinced to stop by this study. An effect in mice (and in a small human trial) isn't definitive and won't change my habits. Also, if being able to have AS helps some people stick with a healthy LCHF diet, then surely that's got to be better for them than the carb equivalents?
    Reply: #16
  15. Johnny D
    Stopped drinking diet soda about 15 years ago and lost 20 lb.. I don't think the diet drinks are healthy.
  16. erdoke
    This attitude reminds me of the guy who is driving on the wrong side of the highway and calls the police to complain about the huge number of idiots he needs to avoid on the road...
    First of all I would like to see very firm evidence that anything bearing "artificial" in its name is safe.
    You are not convinced about the results of this study, so I'm wondering how much evidence you assessed to get convinced about the safety of consuming artificial junk instead of "natural" junk? Also, while I agree that ASs might be helpful in getting rid of one's addiction to sweet taste, why should anyone keep the AS long after this process? The gradual removal of AS seems to be a good approach, but not over years, rather months.
    I am only fully convinced about the safety of drinking spring water, but at least that one can easily go up to 2 gallons/7 liters per day if needed. :o)
  17. Alain
    "Why use fake when stopping real sugar?"

    Because they are junkies.

  18. Colyn
    I eat a LCHF diet but still have a sweet tooth, especially after dinner. I like to drink chai tea and coffee but couldn't do it without some sort of sweetener -- we currently only have stevia in the house. But I also love dark chocolate and can't eat that without a little sugar in it (80% cocoa content or more). A little splurge of delicious chocolate is okay with me.
  19. Tom Welsh
    For gin & tonic, obviously! We need diet tonic... but only half a small glass. (The rest is gin, ice, and sliced citrus fruit).
  20. Mark
    Its a bit early for me to offer this up as I only read this new research last week and have just, this morning, finished my course of Norfloxacin.

    I live in the tropics and sweat in a gym each day and till about 5 months ago used to drink about 2 litres of aspartame added water... Cos it tastes OK and its a lot to drink!

    I have been low carb for two years dropping from 195 pounds to 175, but I still have a teeny bit of stomach fat. Thats 88 kgs to 79 kg

    For the last year or so my fasting Blood Glucose has been above 120/6.5 and been told its in the diabetic range. So I bought a glucose meter and spear my pinkies mulitple times per day.

    My average Blood Glucose over the last 14 weeks is 117/6.49.
    After one week on Norfloxacin is its averaging 107/5.94. :)
    The drop occured within 2 days and I have had my first sub 100 BG!!! Now I have had 3 sub 100/6. Thats normal range! And only one was fasting, the other two were day and before bed.

    I used Norfloxacin as it was all I had.

    Today I will start on a probiotic replacement and start potato resistant starch.

    I hope it stays down!
    Obviously , I am keeping charts of it all but can't see how to post it here.

    Anyway, as a lab rat I feel great so don't hassle me about self administering antibiotics without prescription... They were out of date as well :)

  21. david
    Me too. I've lost weight magnificently on LCHF, I consider my results remarkable. But I have consumed quite a bit diet soda during my journey and in an odd way, they have helped in spite of their downside like how they affect your teeth (remember that the PH in soda's of all types are bad for your teeth says my dentist colleague.).

    However, I have often noticed a hunger spike when I use them, but, it's just time to avoid aspartame as I have sugar. Oh well.

    It sure feels good not to be heavy anymore and not recoil at pictures of myself.

  22. Marilyn
    Stevia had been my favorite sweetener for well over a decade. For years, I had occasional mysterious symptoms, until one day a lightbulb went on. I remembered reading that one of the "good things" about stevia was that it worked on the pancreas to stimulate the release of insulin, keeping the blood sugar low. Too low for some of us who don't need our blood sugar lowered, it seems. I did some quick online research, and found others who had also had problems. The action of stevia is not unlike that of the sulfonylureas -- a class of drugs used for diabetes. I was interested to find this recent post:

    I've never used a lot of sweeteners of any sort, so for now, a bit of saccharin and some erythritol will suffice.

  23. John
    Liquid Sucralose (EZ Sweetz) - Used in Hot Beverages, Fat Bombs, Almond/Coconut Milk
    Aspartame - Consumed in Coke Zero, Crystal Light

    - Didn't prevent weight loss while doing LCHF
    - Hasn't caused weight gain now that I'm in my normal weight range.
    - Hasn't kept carb cravings alive

    I can give up aspartame, but I'm going to wait for more evidence before I give up liquid sucralose.

  24. GuyJeb
    Then do you believe that Sparkling Water is bad for us since it is also Soda? as in "Soda Water" ?
    Reply: #25
  25. erdoke
    One thing I like in Paleo is the idea of sticking to proven foods. There is not much debate about clean spring water being healthy or not. Whatever is changed becomes artificial and immediately raises concerns.
    I do drink carbonated water occasionally, but prefer squeezing some lemon juice into the regular spring water if I feel the urge for supporting acidity in my stomach.
    Back to sweeteners, I don't see the reason why some chemicals should be preferred over low amounts of sugar. A 100 g bar of dark chocolate with 90 % cacao contains 9 g of sugar. Eating 20 g at a time loads you with as much as 1.8 g. I rather take that risk over substituting with chemicals.
  26. Fernán
    Interesting! I have a question, though: what do you guys drink when clubbing? If you don't drink alcohol, don't drink sodas with sugar and now we don't drink sodas with artificial sweeteners, what's left on the list?
  27. Zepp
    I dont know how others do.. but I drink wine!
  28. Dan
    my blood suger has been between 82- 88 and i was told i need to take medicine. Thank you LCHF and losing weight too. Dan
  29. Nelson
    I follow a low-carb, high protein diet, which keeps my blood sugar under control (Type 2 diabetic), and I've been losing weight like crazy.... and this is with drinking two litres of diet soda a day on average. I've checked -- none of the big three artificial sweeteners (Aspartame, Sucralose, Ace-K) have any impact on my blood sugar.
  30. JaneFW
    Tequila, lime and soda? Or a Bloody Mary, vodka, tomato juice and Lea and Perrins (more of an aperitif than for clubbing)? Or a gin or vodka martini, ie a bit of vermouth and gin/vodka? Otherwise you're on shots, which could be dangerous...
  31. NANCY
    My daughter had seizures for 20+ years. Had every test known to man and no one could tell us what was causing them. We took her to a top university and no answer. Since she has been diabetic since 9 MONTHS old, “sugar free” is all that we ever fed her. She tried a store brand of splenda one night and her seizures were unbelievable. She gave up all artificial sugars and NO seizures. The only thing she uses is stevia in the raw. She won’t even chew a piece of sugar free gum.

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