Sucralose is a synthetic sweetener that enjoys versatile use in beverages, foods, dental care products, and generally as a sugar substitute.
Although it has been approved for over 20 years, numerous studies suggest that sucralose may have harmful side effects on human health.
Therefore, we’ll take a closer look at how bad sucralose is and whether you should use the sweetener as a sugar substitute on keto in this article.
What Is Sucralose?
Sucralose is better known by 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 still 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 about 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:
- Chewing gum
- Fruit juice cocktails
- Diet sodas
- Ice cream
Besides, many low-fat, low-calorie, sugar-free, and low-sugar foods are containing 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 Bad for You on Keto?
At first glance, sucralose appears to be a suitable option for the keto diet. The sweetener is sugar-free and 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 an intelligent option.
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 when 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 Promotes Cravings on Keto
More and more studies suggest that artificial sweeteners cannot activate food reward pathways in the same way as 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 true 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 on Keto
Since it lacks the 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 levels are high, stored fat cannot be broken down and burned for energy (Meijssen et al. 20014).
Therefore, to determine whether sucralose is keto-friendly and can help with weight loss, we need to study its effects on insulin levels.
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 the journal 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.
Aspartame vs. Stevia vs. Sucralose
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 was able to increase insulin levels more than regular sugar.
Blood sugar was also highest with aspartame after 30 minutes, although it did not initially spike as steeply, such 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 more recent study showed no significant differences among the three sweeteners over three hours after consuming a sweetened beverage (Tey et al. 20178).
In summary, from this perspective, aspartame is about as unhealthy as sugar.
Due to lower peak levels, stevia performs better in direct comparison to aspartame and sucralose.
In particular, the significant effect on blood sugar makes sucralose probably the worse option than stevia when it comes to weight loss.
Nevertheless, stevia also has significant drawbacks and is by no means 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).
Side Effects of Sucralose on Keto
Although the U.S. Food and Drug Administration had already granted full approval to 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 after all.
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, it might be a bad idea if you use sucralose or Splenda for baking.
Sucralose Promotes Insulin Resistance and Diabetes
When consumed with carbohydrates, sucralose can lead to insulin resistance and weight gain (Dalenberg et al. 202013).
Also, consumption of diet sodas, including those containing sucralose, may increase the risk of type 2 diabetes, according to a study published in the journal 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).
The Sweetener Could Be Harmful During Pregnancy
Critical researchers say insufficient safety data exist for the use of artificial sweeteners in pregnant or breastfeeding women and children.
The same is true for 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 Bad for You 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.
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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