The Truth Behind Artificial Sweeteners and Other Risks to Consider

CNET

12-05-2025

Last March, a new study published in the Nature Metabolism journal concluded that artificial sweeteners, like those in diet soda, can make you feel hungrier. The findings state that sucralose, the artificial sweetener studied, "can affect key mechanisms in the hypothalamus responsible for appetite regulation, and that indulging fair amount of artificial sweeteners may "ultimately influence appetite regulation and metabolic responses over time."
The latest research on sucralose isn't the first to suggest that sugar substitutes don't always lead to healthier outcomes. In August of 2024, Cleveland Clinic research found a link between erythritol -- a sugar substitute in many baked goods and sweets -- and a potentially higher risk of cardiovascular events like a stroke or heart attack.
Published in Arteriosclerosis, Thrombosis and Vascular Biology, the study found that erythritol had a blood-clotting effect, unlike glucose found in regular sugar. Erythritol is a sugar alcohol used as a low-calorie sugar substitute. Though it occurs naturally in some fruits, it's added to foods in much higher amounts. It's also different from other sugar substitutes like aspartame or sucralose.
While the study was small and does not prove causation, its findings are important because of how commonly artificial sweeteners and low-calorie sugar substitutes are touted as the healthier option -- particularly to people and who may already be at a higher risk for heart disease. They've also gained some popularity as a keto-friendly option. The findings add to similar existing research on erythritol and cardiovascular risk done by the clinic which was published in Nature Medicine in 2023.
Artificial or low-calorie sweeteners like erythritol are often added to foods like baked goods.All of this recent news follows the 2023 advice from the World Health Organization to not use sugar substitutes as a means for long-term weight control or management, as it doesn't tend to work.
"Many professional societies and clinicians routinely recommend that people at high cardiovascular risk – those with obesity, diabetes or metabolic syndrome – consume foods that contain sugar substitutes rather than sugar," Dr. Stanley Hazen, senior and corresponding author of the newer erythritol study and chair of Cardiovascular and Metabolic Sciences in Cleveland Clinic's Lerner Research Institute, said in Cleveland Clinic news release.
"These findings underscore the importance of further long-term clinical studies to assess the cardiovascular safety of erythritol and other sugar substitutes."
The Centers for Disease Control and Prevention advises people to approach sugar substitutes the same way they should approach real sugar: with moderation. The difference, though, is that low-calorie or zero-calorie sweetener options have different health benefits and risks than regular sugar. And because sugar substitutes or artificial sweeteners come in such different forms, it makes the health benefit-risk profile even harder to pin down.
Here's what to know.
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Types of alternative sweeteners
Before diving into sugar versus sugar alternatives, it's helpful to know what alternative sweeteners actually are -- there are three types of alternative sweeteners, all with their own uses, benefits and drawbacks.
Artificial sweeteners are what most people typically think of when considering sugar alternatives: Splenda (sucralose), Sweet'N Low (saccharin), Equal (aspartame) and Sweet One (acesulfame K). Another, called Newtame, uses a less popular sweetener called neotame.
These sweeteners can be 200 to 700 times sweeter than table sugar (sucrose) and they have zero calories, which is why they're called non-nutritive sweeteners. The only exception is aspartame, which does have calories, but the amount is often considered negligible because you need very little aspartame to achieve an intensely sweet taste in foods and drinks.
Sugar alcohols are a type of carbohydrate that occurs naturally in plants, but they can also be man-made in labs. Most sugar alcohols are processed from sugars and starches through a chemical manufacturing process.
They do contain some calories, although not as many per gram as sugar. Some sugar alcohols you may have seen on food labels include sorbitol, erythritol, maltitol and xylitol: They're really common in sugar-free gum, protein bars, low-calorie ice cream and other processed foods, especially diet foods. You can also find some sugar alcohols in dental products, like toothpaste and mouthwash.
They're called sugar alcohols because their chemical structure resembles both sugar and alcohol, but despite the name, these low-calorie sweeteners don't contain ethanol, the type of alcohol that leads to intoxication.
Novel sweeteners include newer sugar alternatives that are difficult to place in the above two categories. The most recognizable example: stevia. Stevia, or rather stevia extract, is a popular plant-based sweetener with almost no calories. It doesn't have a chemical structure like artificial non-nutritive sweeteners, nor sugar alcohols -- so it hovers in novel sweetener limbo.
Other novel sweeteners include monk fruit extract (a zero-calorie sweetener that comes from a fruit native to China) and tagatose (an artificial sweetener that is actually less sweet than table sugar).
The Food and Drug Administration considers all of the above sugar alternatives as "high-intensity sweeteners," and they all come with several pros and cons.
Benefits of sugar alternatives
Sugar alternatives may be one of the most scrutinized food additives around. Like any food additive, they must be authorized for consumption in the US by the FDA. The FDA currently recognizes many sugar alternatives as safe to eat, and research suggests that they can offer health benefits, especially when used for specific purposes, such as keeping diabetes under control.
Could potentially help with (short-term) weight loss or maintenance
If you're looking to curb your calorie intake to lose weight, but don't want to give up sweet foods and drinks, sugar substitutes are an easy first tool to try: You get the taste you desire, but without the calories.
But recent research has reanalyzed this logic and suggests that alternative sweeteners may not always help with weight loss efforts (more about this under drawbacks on alternative sweeteners below). But for people who are cognizant of their overall food and drink consumption, low- or zero-calorie sweeteners may aid in weight loss.
In 2023, the WHO put out a statement saying that nonsugar sweeteners like aspartame, sucralose and stevia shouldn't be used for longterm weight control. (The WHO says this does not apply to low-calorie sugars or sugar alcohols.)
If you are trying to lose weight, it's important that you don't inadvertently replace these calories elsewhere. Having a diet sweet tea instead of a regular sweet tea, for example, may lead you to eat more calories because you "saved" some by drinking the diet beverage.
Read more: Can Diet Sodas Cause Cancer? Making Sense of the WHO's Aspartame Classification
Help to keep blood sugar under control
Sugar substitutes can help people with diabetes satisfy cravings without causing rises in blood sugar like real sugar does.
A 2012 statement from the American Heart Association and American Diabetes Association says that non-nutritive sweeteners can help people reduce their sugar intake and overall calorie intake when used with good judgment, although the benefits won't apply if you overcompensate and get too much sugar from other foods.
If you have diabetes, talk with your doctor about which sugar substitutes or sweeteners you should look for on food labels so you can satisfy your sweet tooth safely, taking your whole health history into account.
Good for oral health
If one thing is for sure, sugar alternatives can help with dental health. Cavities form when bacteria in your mouth ferment sugar, which creates acid. The acid wears down your teeth, eventually breaking through the enamel and causing a cavity. Since sugar substitutes don't contain sugar, they can help prevent the tooth decay process.
Read more: Can Prebiotic Soda Hurt Your Teeth? Here's what Experts Say
Sugar alternative drawbacks
Equal is another popular alternative sweetener. The original version uses aspartame, a non-nutritive sweetener that's been scrutinized for decades because of reported side effects, such as digestive symptoms. The science on aspartame and potential side effects is still conflicting, and the WHO labeled it as possibly carcinogenic in 2023.
Equal
Non-nutritive sweeteners, sugar alcohols and novel sweeteners definitely have their advantages, as evidenced above. They have potential pitfalls, too -- not everything about those colorful calorie-free packets is so sweet.
May disrupt your gut health
Research has shown that some artificial sweeteners (saccharin and sucralose), as well as stevia, can change the composition of your gut. If sweeteners reduce the number of good bacteria and hamper the growth of good bacteria, you may wind up with an imbalanced gut, which can lead to symptoms like cramping, gas and bloating.
This 2019 review of studies suggests that some sweeteners can have negative effects while others, specifically sugar alcohols, may have positive effects. Research in animals has also shown negative changes to gut bacteria after consumption of artificial sweeteners, though more research is needed in humans to determine the true long-term effects of sugar alternatives on gut health.
Can cause digestive upset
Whether or not sweeteners disrupt your gut microbiome, they are known to cause unpleasant digestive symptoms. Most of this evidence is anecdotal, beginning decades ago with complaints about cramps after consuming aspartame.
Though more studies are needed to determine the relationship between alternative sweeteners and digestive distress, research does note that some digestive symptoms may be due to changes in the gut bacteria or the way that alternative sweeteners move through your digestive tract.
For now, it's best to monitor your symptoms, if any, when you consume different sweeteners (and stay away from the ones that cause distress).
Can actually increase cravings for sweets
Alternative sweeteners may have few or zero calories, but that doesn't mean your sugar cravings will stop. Research points out that the desire for sweet foods doesn't depend on the origin of the sweetness, and that people can develop cravings for sweet foods even in the absence of calories, likely because that combination -- sweet taste and zero calories -- confuses your body and disrupts appetite regulation.
In one eyebrow-raising animal study, rats were allowed to choose between saccharin-sweetened water and intravenous cocaine, and the vast majority (94%) chose sweetened water. The authors note that the same preference was observed with sugar-sweetened water, so it can't be said that artificial sweeteners are more addictive than sugar -- just that sweetness in general can be highly addictive.
Linked to longterm weight gain
Some research suggests that artificial sweeteners, despite having few or no calories, may lead to weight gain when consumed frequently over time. One study even showed that drinking artificially sweetened soda coincided with an increase in waist circumference nine years later.
Another found that people who used non-nutritive sweeteners had a larger increase in BMI than people who didn't consume non-nutritive sweeteners at an eight-year follow-up, except among people who exercised regularly.
The reasoning behind this isn't clear, but researchers think it may have to do with metabolic changes induced by alternative sweeteners or because of compensatory behavior -- that is, thinking things like, "I drank a diet soda so I can have extra cake."
The takeaway
A little bit of sugar won't hurt you, especially in the form of fruit. If you have a medical condition that may be affected by sugar intake, talk to your doctor about consuming proper portions.
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The current consensus is that scientists just don't know enough about the long-term effects of sugar alternatives -- artificial sweeteners, sugar alcohols or novel sweeteners -- to make definitive claims, or whether sugar or alternatives are better in the long term.
Both sugar and sugar alternatives are OK to eat in moderation -- what truly matters is that you make smart food choices based on your current health status and medical conditions, as well as how sugar or alternative sweeteners make you feel. After all, food is meant to be enjoyed.
It's probably a good idea, for example, to stay away from sugar alcohols if you get the laxative effect. Likewise, you may want to limit table sugar if you tend to get sugar headaches or if you have diabetes. But on the tails on more research on cardiovascular risk and one sugar substitute, it's best to speak with your doctor about which sweeteners to choose if you do buy a lot of food marketed for dieting, low-calorie or sugar-free options.
If you're worried about the harmful effects of either -- sugar or alternatives -- a good rule of thumb is that whole food is usually better. Choose an apple over apple juice; choose fresh-squeezed lemonade over a zero-calorie lemonade mix; choose homemade granola over store-bought.
Most of all, choose whatever best suits your health needs and makes you happy.