Are Artificial Sweeteners Safe for Ketosis?


  1. Guide to Artificial Sweeteners and How They Affect Ketosis
  2. Aspartame
  3. Sucralose
  4. Saccharin
  5. Acesulfame-potassium
  6. The Main Concern with Artificial Sweeteners
  7. All Natural Sweetener Substitutes

Artificial sweeteners certainly have bad reputations among the health community.  In the keto community only a few sweeteners have any love, and they are not labeled artificial sweeteners.

However, we want to give you the facts and reasons for how artificial sweeteners affect ketosis so that you can make up your own mind. 

In our opinion at Keto Domain, artificial sweeteners are not a healthy option for people whether they are on the keto diet or not.

But even though we don't condone it, we understand that some people like diet coke (sweetened by artificial low or no calorie sweeteners) and they want to know if they can safely drink it on the keto diet.

Artificial sweeteners are chemicals that have a sweet taste, usually much sweeter than regular sugar.   They are not naturally found in foods.  However, some artificial sweeteners do occur naturally in the body in their molecular form.

You may be on the keto diet because you want to improve your health without additives or chemicals.  If that is the case, you should not use aspartame, sucralose, acesulfame-potassium or saccharin as a sweetener on the keto diet.  But there are other reasons why you should not use artificial sweeteners when on the ketogenic diet, and those reasons are not solely if one Diet Coke effects ketosis (does one Diet Coke effect ketosis?  Read on to find out!)

To examine the effects of these sweeteners on ketosis, we look at the main artificial sweeteners in terms of changes in blood glucose and insulin levels, as well as caloric quantities.

Guide to Artificial Sweeteners and How They Affect Ketosis


Aspartame is a chemically derived sweetener.  Aspartame is commonly found in foods like diet coke.  It does contain 4 calories per gram, so it is not calorie free.[i]  However, in one packet of Equal there is only 37 mg of aspartame which is 0.15 calories.  A 12 oz can of diet coke contains about 200 mg of aspartame which is 0.8 calories.

Aspartame has been found to be 180-200 times sweeter than sucrose.[ii]

Does aspartame affect ketosis?

When ingested, aspartame has not been shown to affect blood glucose or insulin levels in short term studies; if only considering these terms that makes aspartame keto friendly enough as an artificial sweetener for ketosis.[iii]  Be aware that aspartame does contain calories and does have a limited recommendation on use.

Although aspartame does not directly affect ketosis, many people report having weight loss stalls when using aspartame; others have no weight loss problems.  Is aspartame keto?  We don't recommend it - but one diet coke should not take you out of ketosis.

Aspartame Risk Factors

Aspartame got a bad rap because when it is metabolized in the body, one of the chemicals it breaks down into is phenylalanine.  Phenylalanine is toxic to people with Phenylketonuria disease, a disease where the body has difficulty metabolizing phenylalanine.

Otherwise aspartame has been deemed safe at a maximum intake of 50mg/kg body weight/day by the FDA.   There have been few studies that have linked aspartame to cancer, but these were in extremely high doses.


Sucralose is a chemically derived sweetener.  Sucralose is commonly found in foods like Gatorade Propel water and Breyer's low carb ice cream.  It is a zero calorie sweetener.[iv]

Sucralose has been found to be 450-600 times sweeter than sucrose.[v]

Does sucralose affect ketosis?

When ingested by itself, sucralose has not been shown to affect blood glucose or insulin levels.

However, in one study over 4 weeks and daily use of sucralose has shown to have effects on GLP-1, possibly reducing insulin sensitivity.  In addition, when ingested with glucose, sucralose has been shown to increase blood glucose levels.[vi]  

Bottom line: Having an occasional drink containing sucralose should not effect ketosis, but beware of frequent prolonged use on other health factors.

Sucralose Risk Factors

Besides the potential effects listed above, there are actually more risk factors associated with sucralose including effects on gut bacteria and cause interactions with medications.

However, sucralose has been deemed safe at a maximum intake of 5mg/kg body weight/day by the FDA, equivalent to 23 packets/day.


Saccharin is a chemically derived sweetener.  Saccharin is commonly found in Sweet'N'Low which is the pink packet of sweetener found at the table in many restaurants.  It is a zero calorie sweetener.

Saccharin is about 300 times sweeter than sugar.  It has a bitter after-taste.

Does saccharin affect ketosis?

Saccharin is non-calorie and does not raise blood insulin or glucose levels.

Saccharin Risk Factors

The FDA has been deemed safe at less than 15 mg/kg body weight per day, equivalent to 45 packets.

In the past it has been associated with cancer risks, but has since been deemed safe at the FDA consumption limits.


Acesulfame-K is a chemically derived sweetener.  Acesulfame-K is commonly found in diet foods and is combined with other artificial sweeteners.  It is a zero calorie sweetener.

Acesulfame-Potassium is about 200 times sweeter than sugar.   Acesulfame-Potassium may have a bitter after taste.

Does acesulfame-potassium affect ketosis?

Acesulfame-K is non-calorie.  It does not affect blood glucose levels, but it does affect blood insulin levels the same as glucose would.  It is not recommended for ketosis.

Acesulfame-potassium Risk Factors

The FDA has been deemed safe at less than 15 mg/kg body weight per day, equivalent to 23 packets.

Acesulfame-K produces a by-product that is toxic to the body, but only in extremely large doses.

The Main Concern with Artificial Sweeteners

The main issue we have with artificial sweeteners, or any chemicals not naturally occurring in foods, is the long term effects on the body.  Some of these long term effects are difficult to study in the body.

The concern with artificial sweeteners is that over frequent and long-term use, they may change the bodies responses to glucose and insulin.[vii]  They have been linked to increased weight gain and lowering satiety, causing overeating.

Adding chemicals to your body is never a recommended practice, especially when the long term effects have not been fully studied.  Instead, try using an all natural sweetener like stevia or erythritol - both naturally derived non-caloric sweeteners.

All Natural Sweetener Substitutes

Don't despair, there are replacement options for the artificial non-caloric sweeteners.  Naturally derived sweeteners such as stevia, erythritol or monk fruit may be a better option for your health.  Read here to learn our summary of these all natural sweeteners.

Because stevia is so sweet and has a somewhat bitter aftertaste, a lot of brands add artificial ingredients to improve the taste.  However, that defeats the purpose of using an all natural product.  That's why our preferred brand of stevia is the 365 Whole Foods Brand.  It comes in liquid form so is highly concentrated and easy to use.

Our preferred brand of erythritol is Anthony's because it is pure erythritol, and affordable in bulk.  In this product the erythritol comes as a granular sweetener.

In Conclusion...

If you are in a pinch, one diet coke a month should not hurt your ketosis.  But we do not recommend it because of adverse health effects and because the long term effects of these artificial chemicals are not known.

If you are really concerned about the effects it may have, you can test yourself with blood glucose and blood ketone monitors.  Take your readings before and after drinking a small serving of artificial sweeteners to test if they will ruin your ketosis.

Check out our guide to sweeteners for the ketogenic diet for the most thorough review of all types of sweeteners and how they will affect your ketosis.


[i] Sanchari Chattopadhyay, Utpal Raychaudhuri, and Runu Chakraborty.  "Artifical Sweeteners, A review"

[ii] Godshall MA.  "The Expanding World of Nutritive and Non-Nutritive Sweeteners."

[iii] Stephen D. Anton, Corby K. Martin, Hongmei Han, Sandra Coulon, William T. Cefalu, Paula Geiselman, Donald A. Williamson.  "Effects of stevia, aspartame, and sucrose on food intake, satiety, and postprandial glucose and insulin levels."

[iv] Sanchari Chattopadhyay, Utpal Raychaudhuri, and Runu Chakraborty.  "Artifical Sweeteners, a review"

[v] Godshall MA. "The Expanding World of Nutritive and Non-Nutritive Sweeteners."

[vi] Pepino MY1, Tiemann CD, Patterson BW, Wice BM, Klein S.  "Sucralose affects glycemic and hormonal responses to an oral glucose load"

[vii] Susan E. Swithers, "Artificial sweeteners produce the counterintuitive effect of inducing metabolic derangements"

  1. Appreciate your honesty about aspartame. Sometimes you need a diet soda to break up the monotony and it is good to know it won’t ruin ketosis. People get so high and mighty when it comes to adding chemicals to the diet.

    1. I can’t help but be honest, if one soda gives you that “break” and helps you stay on the diet, it shouldn’t hurt you. I personally don’t do diet soda because it makes me crave even more sugar, but everyone is different. Thanks for commenting!

  2. Thank you for this information! As I’m trying desperately to decrease my weight to a healthy one, I’ve heard conflicting storie. Your research has helped my make my choices easier!

Leave a Reply

Your email address will not be published.

Enjoy learning from our website, or have you received personal help from Janine?  Please consider donating to help fund our site!

Donate Here

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to and affiliated sites.