How Bad Is Sucralose on Keto?

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Sucralose | Bad on Keto | Cravings | Insulin | Alternatives | Side Effects

Sucralose is a synthetic sweetener versatile in beverages, foods, dental care products, and generally as a sugar substitute.

Although it has been approved for over 20 years, numerous studies suggest sucralose may harm human health.

Therefore, this article will examine how bad sucralose is and whether you should use the sweetener as a sugar substitute for keto.

What Is Sucralose?

In addition to aspartame and acesulfame potassium, the food industry commonly uses a third synthetic sweetener called sucralose.

Sucralose is better known as a sweetener brand you might recognize for its yellow packets – Splenda.

Also, in Europe, sucralose is labeled under ingredients by E number 955. In the U.S., food producers must also mark the sweetener on the packaging.

As its name suggests, sucralose is related to sugar but has no calories.

It is produced by chlorinating sucrose. In short, chemics add chlorine atoms to regular sugar in the lab.

For this reason, unlike sugar, our bodies can no longer digest sucralose properly. Therefore, the sweetener is said to have both zero calories and zero net carbs.

Also, sucralose is 600 times sweeter than regular sugar (Chattopadhyay et al. 20141).

In addition to the Splenda brand, you can also find sucralose in generic artificial sweeteners. It comes in granulated and liquid forms. Sugar-free and low-calorie syrups also often contain sucralose.

Moreover, the following foods may contain sucralose:

  • Candies
  • Chewing gum
  • Toothpaste
  • Fruit juice cocktails
  • Diet sodas
  • Ice cream

Besides, many low-fat, low-calorie, sugar-free, and low-sugar foods contain sucralose. Therefore, you should always check the label on such products.

In most cases, however, it tends to be healthier to avoid such products entirely.

Is Sucralose Keto?

At first glance, sucralose is a suitable option for the keto diet. The sugar-free sweetener contains little to no carbohydrates, depending on the brand.

However, when we reflect, we must question whether highly processed foods and lab-created chemicals are intelligent options.

Although many fitness drinks or protein bars are sold to us as premium products for serious money, they are not much different from other junk foods containing synthetic sweeteners.

Some call this approach dirty keto. On the other hand, I prefer real food after sucralose has side effects that many people might not know.

Sucralose on Keto Promotes Cravings

More and more studies suggest that artificial sweeteners cannot activate food reward pathways like natural sweeteners.

In short, the lack of calories generally means the reward component is missing.

While magnetic resonance imaging studies showed that glucose ingestion prolongs signal depression in the hypothalamus, the same is not valid for sucralose (Yang 20102).

As a result, sucralose, as well as other low-calorie sweeteners, can fuel cravings.

For this reason, one study had to conclude that consumption of intense sweeteners does not lead to the desired calorie reduction due to increased appetite (Bellisle et al. 20073).

Sucralose Elevates Insulin Levels

Since it lacks macronutrients, the sugar-free sweetener should not cause an increase in blood glucose levels.

But is blood sugar the only thing that matters to ketosis?

People tend to forget that it is not the blood sugar level that matters for weight loss but rather its effect on insulin, our storage hormone.

Besides weight gain and loss, insulin also regulates the metabolic state of ketosis.

Accordingly, when insulin is elevated, stored fat cannot be broken down and burned for energy (Meijssen et al. 20014).

Therefore, we need to study its effects on insulin levels to determine whether sucralose is keto-friendly and can help with weight loss.

Nowadays, researchers can predict about 75% of gain and loss in overweight individuals using insulin levels (Kong et al. 20135).

Finally, the storage hormone has the task of storing supplied energy the body is not immediately demanding. Therefore, the higher the insulin level, the more efficient the fat accumulation.

Against this background, a study published in Diabetes Care compared drinking water with and without sucralose.

Oral intake of the sweetened water increased the test subjects’ insulin levels by up to 50 percent (Pepino et al. 20136).

Thus, this synthetic sweetener also has a significant effect on insulin production. It inhibits weight loss and, in sufficient quantities, can kick you out of ketosis.

Sucralose E955 is a sweetener that could be harmful

Aspartame vs. Stevia vs. Sucralose on Keto

As a decades-old ingredient in diet soda, aspartame, or E951, is the most well-known synthetic sweetener. Therefore, it sets the bar for sucralose as well as plant-based sweeteners.

One study compared blood sugar and insulin levels after consuming stevia, sugar, and aspartame in conjunction with a meal.

In this study, aspartame increased insulin levels more than regular sugar.

Blood sugar was also highest with aspartame after 30 minutes, although it did not initially spike as steeply as after sugar consumption.

On the other hand, people who consumed stevia showed the weakest reactions during the short period (Anton et al. 20107).

A recent study showed no significant differences among the three sweeteners over three hours after consuming a sweetened beverage (Tey et al. 20178).

From this perspective, aspartame is about as unhealthy as sugar.

Due to lower peak levels, stevia performs better than aspartame and sucralose.

In particular, the significant effect on blood sugar makes sucralose probably the worse option than stevia regarding weight loss.

Nevertheless, stevia also has significant drawbacks and is not the holy grail of sweeteners.

For example, stevia is just as harmful to the intestinal flora as sucralose or aspartame (Ruiz-Ojeda und Plaza-Díaz 20199).

Is Sucralose Bad for You on Keto?

Although the U.S. Food and Drug Administration approved sucralose in 1999, its consumption is still not harmless (FDA 201810).

Doubts about the sweetener are based, among other things, on the fact that it does not pass through the human body unaffected.

According to a toxicology study, not only are parts of sucralose metabolized, but blood glucose, insulin, and GLP-1 levels are also affected (Schiffman et al. 201311).

In summary, there are a few good reasons why you should avoid sucralose not only on a ketogenic diet but in general:

Sucralose Is Bad for You When Heated

Like aspartame, this artificial sweetener is sensitive to heat.

Accordingly, one study suggests that sucralose can form dangerous polychlorinated compounds even at moderate temperatures.

It is also generally considered unstable at high temperatures (de Oliveira et al. 201512).

Therefore, using sucralose or Splenda for baking might be a bad idea.

Sucralose Promotes Insulin Resistance and Diabetes

When consumed with carbohydrates, sucralose can lead to insulin resistance and weight gain (Dalenberg et al. 202013).

Also, diet sodas, including those containing sucralose, may increase the risk of type 2 diabetes, according to a study published in Diabetes Care (Nettleton et al. 200914).

Furthermore, the Atherosclerosis Risk in Communities Study (ARIC) showed that metabolic syndrome was 34 percent more common among light consumers (Lutsey et al. 200815).

Sucralose Is Bad for Diabetics

The Sweetener Could Be Harmful During Pregnancy

Critical researchers say insufficient safety data exist for using artificial sweeteners in pregnant or breastfeeding women and children.

The same applies to people who suffer from migraines, diabetes, or epilepsy (Sharma et al. 201616).

Sucralose Is Bad for Your Gut Health

What also makes sucralose as harmful as aspartame, for example, is its negative impact on gut health.

According to one study, a single packet of Splenda is enough to eliminate 50 percent of healthy intestinal flora (Abou-Donia et al. 200817).

Moreover, recent research states that consuming the acceptable daily intake of sucralose significantly increases the risk of developing tissue inflammation in the gut (Bian et al. 201718).

Sucralose Is a Bad Option on Keto

The simple answer to the question of whether sucralose is safe is no.

Whether on a ketogenic diet or not, the sweetener unleashes unwanted side effects:

  • Promotes metabolic syndrome and diabetes
  • Eliminates healthy gut bacteria
  • May form toxic byproducts

On top of that, sucralose increases insulin levels, inhibiting ketosis and weight loss. Besides, we may not yet be aware of other potential long-term health effects.

Whether or not you choose to use sucralose is up to you. I will continue to avoid artificial sweeteners.

The unpleasant truth is that extreme sweetness is always a problem for weight loss – even in the form of supposedly natural sweeteners.

Is Sucralose Keto FAQ

Is sucralose as bad for you as aspartame?

In short, aspartame and sucralose are about equally bad for you.

Is sucralose bad for gut health?

According to several studies, sucralose alters the gut microbiome. They suggest that as little as a pack of Splenda is enough to eradicate up to 50% of healthy gut bacteria.

Is sucralose safe in moderation?

Recent research suggests that sucralose is not safe. I would not even consume it in moderation.

What is the safest artificial sweetener to use?

Erythritol might be one of the safest artificial sweeteners right now, but this might only be due to a lack of research that can stress out the opposite.



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8Tey SL, Salleh NB, Henry J, Forde CG. Effects of aspartame-, monk fruit-, stevia- and sucrose-sweetened beverages on postprandial glucose, insulin and energy intake. Int J Obes (Lond). 2017 Mar;41(3):450-457. doi: 10.1038/ijo.2016.225. Epub 2016 Dec 13. PubMed PMID: 27956737.

9Ruiz-Ojeda FJ, Plaza-Díaz J, Sáez-Lara MJ, Gil A. Effects of Sweeteners on the Gut Microbiota: A Review of Experimental Studies and Clinical Trials. Adv Nutr. 2019 Jan 1;10(suppl_1):S31-S48. doi: 10.1093/advances/nmy037. PubMed PMID: 30721958; PubMed Central PMCID: PMC6363527.

10FDA. Additional Information about High-Intensity Sweeteners Permitted for Use in Food in the United States. Silver Spring: Food and Drug Administration, 2018. Retrieved 2021 Feb 22, from

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Mag. Stephan Lederer, MSc. is an author and blogger from Austria who writes in-depth content about health and nutrition. His book series on Interval Fasting landed #1 on the bestseller list in the German Amazon marketplace in 15 categories.

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