Are Artificial Sweeteners Bad for You? What the 2023 Evidence Says

Reviewed by the HealthyMag Editorial Team. Last updated: July 2026.

What the 2023 aspartame news actually said

In July 2023, the WHO’s International Agency for Research on Cancer (IARC) classified aspartame as “possibly carcinogenic to humans,” or Group 2B, citing limited evidence for liver cancer (hepatocellular carcinoma) in humans, limited evidence in animals, and limited mechanistic evidence. The headline sounded alarming, but the details matter. IARC groups reflect how strong the evidence is that something could cause cancer, not how much cancer risk you actually face at everyday exposure levels.

Group 2B is the agency’s lowest tier of “possible” carcinogens, and it is a crowded, reassuringly ordinary category. Aloe vera whole-leaf extract, pickled vegetables, and working as a dry cleaner sit in the same bucket. Being in Group 2B means the science is not clean enough to rule a hazard out, not that a can of diet soda is a proven danger.

Just as importantly, on the same day IARC released its classification, the Joint FAO/WHO Expert Committee on Food Additives (JECFA) ran a separate risk assessment and reaffirmed the acceptable daily intake (ADI) of 40 mg per kilogram of body weight. JECFA concluded the data gave no sufficient reason to change that limit. To approach it, an adult weighing about 70 kg would need to drink somewhere in the range of a dozen or more cans of aspartame-sweetened soda every single day, well beyond typical consumption.

The erythritol findings that surprised researchers

Erythritol is a sugar alcohol marketed as “natural” and near zero-calorie, and it is common in keto and “sugar-free” products, often bulking out stevia and monk fruit blends. In February 2023, Marco Witkowski and colleagues at Cleveland Clinic published a study in Nature Medicine reporting that higher blood levels of erythritol were associated with an increased risk of major adverse cardiovascular events (heart attack, stroke, or death) over roughly three years.

The pattern held across validation cohorts in the United States and Europe, and the researchers went further than observation. In laboratory and mechanistic work, high erythritol levels made blood platelets easier to activate and promoted clot formation. In a small human experiment, drinking a beverage containing an amount of erythritol found in many processed foods pushed blood levels high enough, and for long enough, to plausibly matter for clotting.

That combination of a real-world association plus a biological mechanism is what made the study notable rather than easy to dismiss. It does not prove erythritol causes heart attacks, but it is a stronger signal than a lone correlation, and it is prompting more research.

Why the WHO told people not to lean on sweeteners for weight

In May 2023, the WHO issued a guideline advising against the use of non-sugar sweeteners for weight control or to reduce the risk of noncommunicable diseases. The recommendation covers common sweeteners including aspartame, sucralose, saccharin, stevia, and others, and applies to most people other than those with pre-existing diabetes.

The reasoning is grounded in a systematic review: over the long term, non-sugar sweeteners did not appear to help adults or children reduce body fat. The WHO also flagged possible undesirable effects with long-term use, including associations with higher risk of type 2 diabetes, cardiovascular disease, and mortality in adults. Crucially, the WHO itself described this as a “conditional” recommendation, an acknowledgment that the underlying evidence is not strong enough to be definitive.

The honest caveats you should keep in mind

It is easy to read three worrying-sounding announcements and conclude sweeteners are dangerous. The more accurate reading is that the evidence is genuinely mixed and mostly low-to-moderate certainty. Much of it, including the WHO’s weight guidance and parts of the erythritol picture, rests on observational studies, which can show that two things move together but cannot by themselves prove that one causes the other.

Reverse causation is a live concern here. People who already carry excess weight, have diabetes, or face heart risk are precisely the people most likely to choose sweeteners in the first place. That can make a sweetener look like the culprit when it may partly be a marker of who reaches for it. Confounding, measurement limits, and short study windows add more uncertainty. None of this makes the findings meaningless, but it does argue against panic and against sweeping declarations in either direction.

The practical, non-alarmist takeaway

So, are artificial sweeteners “bad for you”? For most people using them in moderation, the honest answer is: probably not dangerous, but not a health upgrade either. In specific situations, such as someone trying to cut back sharply on sugary drinks, a diet soda may be a reasonable stepping stone and a smaller problem than large amounts of added sugar. Sugar in excess carries its own well-established risks, so swapping heavy sugar intake for occasional sweetener use is not obviously worse.

But sweeteners are not a free pass, and the evidence does not support treating “sugar-free” as automatically “consequence-free.” If the erythritol signal holds up, and if the WHO is right that sweeteners do not deliver the long-term weight benefit many people assume, then the smart response is not an endless hunt for the perfect substitute. It is to retrain your palate toward less sweetness overall, from both sugar and its stand-ins, and to make water your default drink. That is the move the current evidence supports most consistently, and it sidesteps the open questions entirely. As always, this article is general information and not medical advice; talk to your own clinician about your specific health situation.

The most defensible move isn’t swapping one sweetener for another, it’s gradually dialing down how sweet your diet is overall and leaning on water.

Frequently Asked Questions

Is aspartame safe?

For most people at normal intake, regulators still consider aspartame acceptable. In 2023, JECFA reaffirmed an acceptable daily intake of 40 mg/kg of body weight, a level you would have to work hard to exceed, roughly a dozen or more cans of diet soda a day for a typical adult. The 2023 IARC classification adds a note of caution but does not overturn that intake guidance.

Does aspartame cause cancer?

There is no proof that it does. IARC placed aspartame in Group 2B, “possibly carcinogenic,” based on limited evidence. That category reflects how uncertain the science is, not a measured cancer risk at everyday exposure, and it includes ordinary items like aloe vera extract and pickled vegetables. At typical consumption levels, current evidence does not establish that aspartame causes cancer.

Is erythritol bad for your heart?

A 2023 Nature Medicine study by Witkowski and colleagues linked higher blood erythritol to more heart attacks and strokes, and lab work suggested it may promote blood clotting. This is a meaningful early signal but not proof, and much of the human data is observational. If you have cardiovascular risk factors, it is reasonable to be cautious with erythritol-heavy “sugar-free” products while research continues.

Are artificial sweeteners better than sugar?

It depends on context. Large amounts of added sugar carry clear health risks, so for someone cutting back sharply on sugary drinks, a sweetener can be a smaller problem in the short term. But sweeteners are not a proven health benefit, and the WHO found they do not help long-term weight control. Neither is a health food; less overall sweetness is the better goal.

Which sweetener is safest?

The evidence does not crown a clear winner, and chasing the “safest” one may be the wrong question. Each option carries some open uncertainty, and erythritol in particular now has a cardiovascular signal worth watching. Rather than swapping one sweetener for another, the most defensible move is to reduce how sweet your diet is overall and rely on water.

Do sweeteners help with weight loss?

Probably not over the long term. The WHO’s 2023 guideline advised against using non-sugar sweeteners for weight control, citing a systematic review that found no long-term reduction in body fat in adults or children. The WHO called this a conditional recommendation because the evidence is limited, but it does undercut the common assumption that “diet” products reliably drive weight loss.

Sources

• World Health Organization / IARC / JECFA (14 July 2023), “Aspartame hazard and risk assessment results released” — aspartame classified Group 2B, acceptable daily intake reaffirmed at 40 mg/kg.
• Witkowski M. et al., “The artificial sweetener erythritol and cardiovascular event risk,” Nature Medicine, 2023 — erythritol associated with higher cardiovascular event risk plus platelet/clotting mechanism.
• World Health Organization (15 May 2023), guideline “Use of non-sugar sweeteners” — advises against non-sugar sweeteners for weight control or reducing noncommunicable disease risk (conditional recommendation).