The Bittersweet Impact of Artificial Sugars on Your Body and Microbiome


One of the seemingly most controversial topics in nutrition is something remarkably sweet: artificial sugars. While sugar itself is something that most people don’t have a problem consuming in moderation, the modern fixation on slim waistlines has piqued interest in artificial sweeteners for their minimal caloric value. With a regular Coke containing 150 calories and a Diet Coke boasting 0 calories and no sugar, the choice might seem obvious. Weight gain isn’t the only concern that artificial sugars claim to alleviate; they are also commonly used among people who suffer from insulin resistance. As opposed to natural sugars, artificial sugar is supposedly designed to not deliver a spike in insulin once consumed. While these benefits are all well and good, do their pros truly outweigh their cons? And how much are these non-nutritive sugars affecting your body and microbiome down the road? Let’s dive in and find out.

The Most Common Culprits

Defined simply, artificial sugars are substitutes for natural sugar. They tend to be sweeter - even up to 200 times sweeter - than real sugar. Like we discussed above, while some artificial sugars may be lauded for their zero to low-calorie content, this doesn’t mean they are inherently beneficial. Currently, the FDA has approved six artificial sweeteners:

  • Aspartame

  • Sucralose

  • Acesulfame K

  • Saccharin

  • Neotame

  • Advantame

The Bittersweet Truth

You might be thinking: FDA-approved, zero calories, and technically sugar-free? This is too good to be true. Unfortunately, modern studies are alluding to just that - a bittersweet reality. According to an article by Harvard Health, how the human brain and body react to sweeteners like the ones listed above is “very complex.” The doctor cited in the article, Dr. David Ludwig, denotes that some of his foremost concerns lie in the psychological effects of artificial sweeteners. He raises the point that people may tend to think they can increase their caloric intakes to offset the non-nutritive intake of artificial sugars. A more concrete concern is that the super-sweetness of artificial sugars can actually erode the way we perceive sweetness over time. In fact, “overstimulation of sugar receptors from frequent use of these hyper-intense sweeteners may limit tolerance for more complex tastes,” says Dr. Ludwig. So those fruits and veggies sitting in your fridge? You may crave them less and less, resulting in consuming foods that ultimately provide less nutritional value.

Addictingly Sweet

This addictive nature has proven true in recent studies, showing that “rats who were exposed to cocaine, then given a choice between intravenous cocaine or oral saccharine, most chose saccharin.” Shock value aside, these artificial alternatives aren’t what we’d exactly call safe. While direct links between artificial sweeteners and cancerous cells continue to escape scientists, the risks and concerns go far beyond that.

The Toll on the Microbiome

The mixed messaging could lie in the fact that, again, these artificial sweeteners are FDA-approved. This approval relied on studies that support the fact that artificial sugars pass through the body unchanged. They are referred to as “metabolically inert,” and are thought to essentially “leave no trace.” Here’s where things get tricky: most of these older studies did not take the human microbiome into account. These FDA approvals have not necessarily weighed the damage that these substances could incur on the microbiome and, in turn, the human body.

Recent studies show that artificial sweeteners could actually exacerbate the issues they aim to solve. While they pass through the body “unchanged,” this means that they are interacting with the microbial universe in the G.I. tract in their full form. Research shows that this interaction could trigger beneficial commensal bacteria to shift into pathogenic strains, or disease-causing bacteria. Even more alarming, emerging studies are proving that this shift in the microbiome could be linked to increased glucose intolerance.

Bottom line: the benefits of non-nutritive sugars do not outweigh the toll on your microbiome and overall health. Get creative in how you approach sweet treats, and know that sugar-containing whole foods can be high in nutrients and have low glycemic loads. Whether natural or artificial, concentrated intakes of sugar in large amounts isn’t good for anyone. So next time you reach for that Diet Coke, think twice about your long-term health.


1 Tandel, K. R. (2011, October). [Critial look at controversy on sugar substitutes]. Journal of pharmacology & pharmacotherapeutics.

2 Strawbridge, H. (2020, January 29). Information on negative effects of artificial sweeteners]. Harvard Health.

3 SH, L. M. S. F. C. L. A. (n.d.). [Review on Overconsumption of sugar-dense foods]. PloS one.

4 Carver-Carter, R. (2022, August 29). [Artificial sweetener effects on microbiome] Atlas Biomed.