What Happens to Your Body When You Eat Artificial Sweeteners

If you were anywhere near a screen in 2023, chances are high that you came across sensational headlines about how your daily Diet Coke habit might be killing you. On the heels of a study in Nature Medicine that suggested a link between one particular artificial sweetener, erythritol, and heart disease, countless stories swirled around social media and on the news about sugar alternatives.

The scientific pendulum has swung back and forth about artificial sweeteners, and it can be tough to separate fact from fiction when a substantial amount of research on the topic (including frequently cited studies about cancer and artificial sweeteners) are performed on mice or rats—and at such high levels that few, if any, humans would actually consume.

The plot thickened even more in July 2023, when the World Health Organization added aspartame, another popular artificial sweetener, to a list of items that are “possibly carcinogenic to humans.” The definition of this category, according to the WHO, is that there is “limited evidence in humans, [and] less than sufficient evidence in experimental animals” that these may contribute to an increased risk for certain cancers. (Progesterone-only birth contraceptives, aloe vera and occupational exposure to dry cleaning also fall under this “possibly carcinogenic” category.)

Before we dive into defining artificial sweeteners and revealing what happens if or when you consume them, let’s cut to the chase: The Food and Drug Administration considers all artificial sweeteners currently on the market to be “generally recognized as safe” (GRAS) when consumed at levels the typical human would.

“There is a large body of research supporting the safety of nonnutritive sweeteners,” says Lauren Harris-Pincus, RDN, founder of Nutrition Starring YOU and author of The Everything Easy Pre-Diabetes Cookbook. “Some studies suggest correlation to disease risk like stroke or obesity; however, they do not prove causation,” she adds, referring to the fact that those who are at a higher body weight, for example, might be more likely to seek out alternative sugar options. “It’s very important to look at the design of the study when evaluating if these sweeteners are right for you.”

What Are Artificial Sweeteners?   

As we mentioned in our guide to sugar substitutes, there are three main categories of artificial sweeteners.

• Nonnutritive sweeteners, like aspartame, acesulfame potassium, saccharin, sucralose, neotame and advantame, which are developed in a lab.
• Plant-based sweeteners, including stevia, allulose and monk fruit, which are derived from plants.
• Sugar alcohols, like erythritol, xylitol, mannitol and sorbitol; calorie-free carbohydrates that are designed to be chemically identical to those found naturally in certain fruits.

“Non-sugar sweeteners all have different chemical structures and are absorbed and metabolized by the body in different ways,” says Valisa E. Hedrick, Ph.D., RDN, a registered dietitian nutritionist, associate professor and the director of the Dietary Assessment Laboratory at Virginia Tech in Blacksburg, Virginia, who has been involved in research about artificial sweeteners for more than seven years. “Some are broken down into different components after eating them, while others are excreted from the body unchanged. Because of this, their impacts on health are likely to vary based on the type consumed.”

Non-sugar sweeteners are also called “high-intensity sweeteners,” Hedrick continues, meaning they are sweeter than table sugar. Depending on the type of artificial sweetener, they can range from 200 to 20,000 times sweeter than table sugar, she says.

Regardless of the category or brand, these all serve the same purpose nutritionally, Harris-Pincus explains: to add sweet flavor to everything from toothpaste and cough drops to yogurt, drink mixes, salad dressings and beyond—without added sugar.

Different artificial sweeteners also have different acceptable daily intakes (ADIs), which are determined by the FDA. Regardless of which category of sweetener we’re considering, you’d need to consume a lot to come near that limit. For perspective, Hedrick says, “You would need to consume anywhere from around 20 to 75 packets or around 14 to 40 cans of diet soda to reach the ADI.”

Just because you can probably safely consume quite a bit of sugar substitutes doesn’t mean that you should, though, Harris-Pincus clarifies.

“Less is more with any food or drink that does not provide essential nutrients such as vitamins, minerals, phytonutrients and fiber. Artificial sweeteners are much sweeter than sugar, so less is needed to achieve the same level of sweetness,” Harris-Pincus says. “As a stand-alone ingredient, I wouldn’t consider nonnutritive sweeteners ‘healthy’ because they do not contribute meaningful nutrients to our diets. However, if someone is using them as a way to consume more nutrient-dense foods such as Greek yogurt, they can certainly play a role in an overall nutritious diet.”

What Happens to Your Body When You Eat Artificial Sweeteners

As we hinted at earlier, not every artificially sweetened food or drink is labeled “diet” or emblazoned with another icon that could help you spot it in a lineup of items sweetened with sugar, honey, maple syrup, corn syrup or other caloric options. 

“Artificial sweeteners are unavoidable to a certain extent. They’re in toothpaste, gum, protein powders and other lesser-known sources,” explains Molly Bremer, M.S., RDN, a registered dietitian nutritionist and the director of Mosaic Nutrition in Washington D.C. “The main concern with consuming artificial sweeteners is that we do not know the long-term effects of intake. There are new artificial sweeteners being manufactured at such a high frequency that it is difficult to create a biomarker (a medical sign in the body) that captures all nonnutritive sweeteners in order to accurately conduct research. Therefore, we have not been able to capture potential drawbacks of artificial sweeteners.”

So while we think they’re safe at the ADIs, we’re continuing to learn more each year and decade about what the ripple effects might be over time. For now, here’s what we know about what happens when you consume artificial sweeteners.

You Probably Won’t See a Substantial Change in Blood Sugar

Evidence suggests that there isn’t a significant positive or negative impact of aspartame, sucralose and stevia on blood glucose control, Hedrick says, so if you’re searching for ways to balance blood sugar, don’t rely on this as a solution. (Instead, consider these 12 healthy ways to lower your blood sugar, and take note of 5 sneaky reasons why your blood sugar might be high.)

We do know, though, that sugar does have an impact on blood glucose, Hedrick says, “and we know that too much sugar is a bad thing.”

You’ll Decrease Your Intake of Added Sugars and Will Consume Fewer Calories

The most recent 2020 to 2025 Dietary Guidelines for Americans suggest aiming for getting less than 10% of daily calories from added sources of sugar. On a 2,000-calorie-per-day diet, that would net out to 200 calories, or about 50 grams (12½ teaspoons) of sugar. The American Heart Association ups the ante and promotes aiming for 6 teaspoons (25 grams) or less of added sugar for women, and 9 teaspoons (36 grams) or less for men daily. 

So what’s the average American actually eating? About 17 teaspoons, the CDC confirms.

“Many people consume artificial sweeteners to decrease sugar intake, calorie consumption or both,” Bremer says. “Technically, artificial sweeteners will replace sugar, and therefore, cut calories.”

If incorporating an artificial sweetener into your diet significantly decreases your added sugar intake (say, you replace a regular soda with a diet soda or spike your coffee with a sugar-free syrup instead of one made with sugar), “there can be a benefit,” Harris-Pincus believes. “The key is replacing your existing sugar intake with a low- or no-calorie sweetener, not simply adding more artificial sweeteners where you didn’t need them. There’s no reason to start using artificial sweeteners, unless it significantly decreases the amount of added sugar you are currently consuming.”

Keep in mind that items labeled “sugar-free,” “keto” or “no added sugars” are not necessarily a health Rx. Some products that contain artificial sweeteners are ultra-processed foods that contain calories without many nutrients, Harris-Pincus says.

You May Have an Easier Time Drinking Less Soda or Sweetened Beverages

If you’re hoping to consume less added sugar and you find that drinks are one of your largest sources, “artificial sweeteners might be a good place to start. If you already enjoy water, though, I wouldn’t suggest going out and starting to drink artificial sweeteners,” Hedrick says.

Not a big fan of plain H2O? Hedrick recommends opting for half regular and half diet soda to get used to the taste, or replacing one to two sodas with diet. Then try to work your way to all diet, and eventually, sparkling water with a splash of lemon or lime or a flavored seltzer.

Over Time, You May Notice Slightly Lower Blood Pressure

There has been promising research that stevia in particular might help slightly reduce blood pressure, but further research is needed, Hedrick confirms. 

“However, it’s important to realize that many stevia products contain erythritol,” Hedrick says, referring to the sugar alcohol that recently scored all that negative press related to heart disease and stroke. If that’s something you’d like to steer clear of until we know more, she says, “Make sure you check the labels!”

You Might Experience Digestive Distress

Headaches and an upset stomach are two sometimes-reported side effects of artificial sweeteners, Harris-Pincus says, noting that “some people report tolerance issues. It’s a very personal choice to use them or not, and I usually suggest people avoid anything that brings unwanted symptoms.”

Your Gut Health Might Be Affected

Research hints that saccharin, sucralose and stevia, in particular, may alter the gut microbiome and lead to dysbiosis, or an imbalance of good gut bacteria and the harmful kind. This may partially be the reason why some individuals experience those unpleasant digestion symptoms; dysbiosis can lead to bloating as well as irritability or other mood changes, anxiety, migraine or even certain autoimmune conditions.

What to Look For When Choosing Artificial Sweeteners

Hedrick is often asked, “Which artificial sweetener is the best one?” Those questions leave out a small but pivotal detail, she believes. The better question: “Which artificial sweetener is the best for me?” 

“All of these non-sugar sweeteners have varying impacts on the body, and it is not a one-size-fits-all approach. When figuring out which is the best one for you—or if you should consume them—it’s important to consider the reason why. There is a shortage of evidence and research on individual types of sweeteners, which is evident in our national and international guidelines,” she concedes.

That means it’s really tough to even provide individualized recommendations on what to look for when choosing artificial sweeteners. As a general rule, though, the more naturally occuring sugars (found in foods like fruit, grains and dairy) and less artificial or added sugars you consume, the better. Beyond that, if you decide to replace some added sugars with artificial options, it’s a personal choice about which flavor you prefer. Ideally, you’re searching for a sweetener that doesn’t come packaged with side effects, such as digestive distress or headaches.

If you wish to avoid these altogether, Harris-Pincus endorses using pureed fruits (like bananas, prunes, applesauce or dates) in baking and other recipes to add sweet flavor with fiber, antioxidants, vitamins and minerals. Or add your own sugar, like honey or maple syrup, in small amounts.

“‘Unrefined sugars like honey, maple syrup, agave or coconut sugar are still added sugars as far as your body is concerned. They may provide very small amounts of some micronutrients, but still count as sugar when considering your daily sugar intake,” Harris-Pincus says.

Overall, connecting to your body and tuning into what it does and doesn’t want can also help transform your relationship with sugar and sweetness, Bremer says. (Intuitive eating can be a brilliant tool to help you and your body become BFFs, she adds.) The ideal endgame is to reduce consumption of added sugar to be at or below the recommended 12½ teaspoon daily upper limit, and not to rely on artificial sweeteners.

Try to limit or avoid artificial sweeteners if you’re pregnant or breastfeeding, Hedrick advises, since we simply don’t know enough about the trickle-down effect. 

“Research shows that non-sugar sweeteners are transferred through amniotic fluid and breast milk to fetuses and infants. The early exposure to non-sugar sweeteners has not been well researched, but we do know that at this age food and taste preferences and dietary patterns are established and intake of non-sugar sweeteners could significantly impact development of these preferences,” Hedrick. 

The American Academy of Pediatrics acknowledges the lack of research, and suggests that manufacturers should clearly state the presence of non-sugar sweeteners on food packages to help consumers make informed choices.

The Bottom Line

Artificial sweeteners are either made in a lab or derived from plants, and are a very low- or no-calorie way to add sweet flavor to foods, drinks and other consumable products. Much more research, especially in human subjects, needs to be done over the long-term to confirm the actual health impacts of consuming these newer sweeteners. 

Currently, it appears that artificial sweeteners can aid in reducing intake of added sugars, and, as a result, calories. Some sweeteners have been linked to beneficial changes in blood pressure, and others appear to be associated with digestive issues and gut health harms.

If possible, seek out naturally sweet foods, like fruit and dairy products with no added sugars. On a daily basis, opt for small amounts of added sugar, and if you choose to add artificial sweeteners to your menu, consume in moderation. And don’t forget a healthy lifestyle includes dessert, too—made with added sugar—when you’re in the mood. For more on this, don’t miss: “I'm a Dietitian and I Eat Dessert Every Day.”