Are Sugar Substitutes Really Better for You? What the Science Actually Says

Sugar substitutes have become almost impossible to avoid.

They're in diet drinks, protein bars, yogurt, candy, gum, tabletop sweeteners and countless other products. The basic idea is appealing: get the sweetness without all the sugar and calories.

But there is a surprisingly complicated question underneath that simple trade.

Are sugar substitutes actually better for us?

The honest answer is: sometimes, possibly—but the long-term health picture is far from settled.

And importantly, "sugar substitute" isn't one thing. Different sweeteners have different chemistry, different amounts of research behind them and potentially different biological effects.

That's why the first practical step is surprisingly simple:

Read the label.

First, know what you're actually eating

Sugar substitutes fall into several broad groups.

Non-sugar sweeteners include substances such as aspartame, sucralose, saccharin, acesulfame-K and stevia-derived sweeteners. They provide little or no energy at the amounts normally used for sweetness.

Then there are sugar alcohols, also called polyols. These include erythritol, xylitol, sorbitol and maltitol. They aren't chemically identical to the non-sugar sweeteners above.

That distinction matters.

For example, the World Health Organization's 2023 recommendation against using non-sugar sweeteners for long-term weight control specifically excluded sugar alcohols such as erythritol and xylitol. WHO's recommendation was also conditional because the long-term observational evidence has important limitations.

So don't lump every sweetener into one bucket.

When you buy a product, check the ingredient list to see which sweetener or sweeteners it contains. The Nutrition Facts panel may also tell you the total amount of sugar alcohols when applicable.

What it generally won't tell you is exactly how many grams of each individual sweetener are in the product.

That makes knowing the ingredient names useful.

Does replacing sugar with sweeteners actually help?

This is where things get interesting.

The obvious argument is straightforward:

Less sugar → fewer calories → less weight gain.

And there is truth in that logic.

Replacing a sugar-sweetened drink with a zero-calorie beverage can reduce calorie intake. Small randomized trials and substitution analyses suggest that replacing sugar-sweetened beverages with non-nutritive sweetened beverages can produce modest benefits for body weight and some metabolic measures.

But that doesn't necessarily mean that consuming non-sugar sweeteners themselves is beneficial for long-term health.

The WHO concluded that non-sugar sweeteners don't provide a long-term benefit for reducing body fat and recommended against using them as a strategy for weight control. The recommendation was conditional, in part because much of the evidence connecting sweeteners with chronic disease comes from observational studies that can be affected by confounding and reverse causation.

The distinction is important:

Replacing sugar with something else may be beneficial without the substitute itself being a health-promoting substance.

Water is a good example. If you're replacing a sugary soda, water doesn't need to be "better than" a sweetener in some biochemical contest. It simply doesn't require the sweetener in the first place.

What about diabetes and heart disease?

This is where headlines can get ahead of the science.

A large 2026 meta-analysis involving more than 3.6 million people reported associations between higher artificial-sweetener intake and several outcomes, including type 2 diabetes, hypertension, heart failure, stroke, coronary artery disease and mortality.

Those numbers sound alarming.

But most of the underlying evidence was observational, and there was substantial variation between studies. An association does not establish that the sweetener caused the disease.

There's an obvious example of why this matters:

Someone who is already overweight, has diabetes or is at high cardiovascular risk may be more likely to choose diet products.

If researchers then observe that diet-product consumers have more cardiovascular disease, the direction of causation isn't necessarily:

sweetener → disease

It could partly be:

higher underlying risk → choosing sweeteners

Or both could be influenced by other factors.

A new 2026 scientific statement from the American College of Cardiology reaches a similar conclusion. It says the long-term metabolic and cardiovascular effects of non-nutritive sweeteners remain inconclusive, noting that observational associations may be influenced by reverse causation and residual confounding. Experimental evidence has also been inconsistent and may differ among sweeteners.

The ACC's practical conclusion is refreshingly simple:

Water and other unsweetened beverages remain the preferred choices for long-term health.

Then there are erythritol and xylitol

These two sugar alcohols have generated some particularly interesting—and concerning—research.

Erythritol

A 2023 study published in Nature Medicine found that people with higher circulating erythritol levels had higher rates of major cardiovascular events during follow-up.

In two validation groups, the highest versus lowest erythritol categories were associated with substantially higher cardiovascular-event risk.

The researchers also found effects involving platelet reactivity and thrombosis in laboratory and animal experiments.

That sounds pretty damning.

But there's a major complication:

Erythritol is also produced naturally by the human body.

So a high blood level doesn't necessarily mean that someone consumed a lot of erythritol. It may partly reflect underlying metabolic differences or disease.

That's one reason the observational findings don't prove that eating erythritol causes heart attacks or strokes.

Then came a small human experiment.

In a 2024 study, 10 healthy volunteers consumed 30 grams of erythritol and showed increased measures of platelet activation and aggregation compared with a glucose control group. The researchers described 30 grams as a quantity commonly found in erythritol-sweetened foods and within the range of daily intake reported by some people.

Critics can reasonably point out that 30 grams is a substantial single dose compared with the amount someone might consume in an individual serving of a particular product.

But the study does demonstrate something useful: under those experimental conditions, erythritol can acutely affect platelet behavior.

Xylitol

Xylitol produced a similar signal.

A 2024 European Heart Journal study found that higher circulating xylitol levels were associated with cardiovascular-event risk. In a small intervention involving 10 healthy volunteers, 30 grams of xylitol increased several measures of platelet responsiveness.

Again, this is not proof that eating xylitol causes heart attacks.

It's a signal that deserves further investigation.

And now the story gets more complicated

In September 2026, researchers posted a preprint that tested the platelet question again.

Fourteen healthy volunteers received either 50 grams of erythritol, 33.5 grams of xylitol, or water in a randomized crossover study.

The researchers found no increase in platelet aggregation or markers of platelet activation, endothelial activation or coagulation after either sweetener. Their laboratory experiments also failed to show increased platelet aggregation.

That's important.

But it doesn't settle the matter.

This was a small study, it was conducted in healthy people, it examined acute platelet effects, and it has not yet been peer reviewed.

Most importantly, it doesn't answer the separate question raised by the earlier observational studies:

Could long-term exposure to erythritol or xylitol be associated with cardiovascular risk in people who already have metabolic or cardiovascular risk factors?

So the new study doesn't simply erase the earlier findings.

It means the platelet story is still unresolved.

And that's exactly where the evidence should leave us.

What about cancer?

This deserves a little more nuance than either "sweeteners cause cancer" or "there's nothing to worry about."

A 2025 systematic review examined 90 epidemiological studies involving several non-sugar sweeteners, including aspartame, acesulfame-K, cyclamate, saccharin and sucralose.

The review found no consistent association or dose-response relationship with cancer for the sweeteners it evaluated.

But there's an important disclosure that readers should know.

The paper was funded by the American Beverage Association, a U.S. non-alcoholic beverage industry trade association, and the authors included employees of Gradient and the American Beverage Association. Gradient and Geosyntec are consulting firms.

That doesn't automatically make the findings wrong.

It does mean the finding deserves to be viewed with appropriate awareness of the funding and authors' relationships.

And there is another reason not to simply call the cancer evidence "reassuring."

A large 2022 prospective study from the French NutriNet-Santé cohort followed 102,865 adults and reported that higher consumption of artificial sweeteners was associated with a higher risk of cancer overall.

The association was stronger for aspartame and acesulfame-K. For total artificial sweetener consumption, the hazard ratio was 1.13; for aspartame, it was 1.15.

Those are relatively modest associations, and the researchers themselves acknowledged important possibilities for selection bias, residual confounding and reverse causality. The study was observational, so it cannot establish that the sweeteners caused the cancers.

Then there's aspartame specifically.

In 2023, the International Agency for Research on Cancer classified aspartame as Group 2B, "possibly carcinogenic to humans," based on what it called limited evidence for cancer in humans, particularly hepatocellular carcinoma, a type of liver cancer.

At the same time, the FAO/WHO Joint Expert Committee on Food Additives concluded that the evidence was not convincing enough to change the existing acceptable daily intake of 0–40 mg per kilogram of body weight per day.

So even within major international health organizations, the terminology reflects two different questions:

Can something potentially cause cancer?

versus

Is the level of exposure people normally receive sufficient to pose a meaningful risk?

Those aren't the same question.

So what should you actually do?

You don't need to panic about every packet of sweetener or piece of sugar-free gum.

But there's also no compelling reason to treat sugar substitutes as health foods.

A sensible approach is:

1. Read the ingredient list

Know whether you're consuming aspartame, sucralose, acesulfame-K, stevia-derived sweeteners, erythritol, xylitol or another sweetener.

Don't assume "sugar-free" means "sweetener-free."

2. Look at how much you're consuming

One product occasionally is very different from a diet built around multiple sweetened drinks, bars, candies and desserts every day.

And remember: the amount of an individual sweetener is generally not separately listed on the label.

3. Don't assume "natural" means safer

Xylitol and erythritol occur naturally and can also be produced by the human body.

That doesn't automatically make them safer—or more dangerous.

Likewise, "artificial" doesn't automatically mean toxic.

The chemistry and the evidence matter more than the marketing category.

4. If you're replacing sugar, consider what you're replacing it with

Replacing a sugary soda with water is a very different nutritional strategy from replacing it with a diet soda.

Both may reduce sugar intake.

But water doesn't require us to answer a complicated question about the long-term effects of a sweetener.

5. Don't overreact to the erythritol and xylitol studies

The cardiovascular findings are interesting enough to take seriously.

They're not strong enough to conclude that consuming these sweeteners causes heart attacks or strokes.

And the latest small preprint finding no acute platelet effect makes the picture more—not less—interesting.

6. Pay attention to the bigger dietary picture

The strongest nutritional evidence isn't pointing toward finding the perfect sweetener.

It's pointing toward eating more minimally processed foods, getting plenty of fiber-rich plant foods and limiting added sugar—particularly sugar-sweetened beverages. The 2026 ACC statement emphasizes that overall dietary pattern and food quality matter more than obsessing over individual ingredients.

The Watchdog Takeaway

Sugar substitutes are not one thing, and the science isn't settled.

Some evidence suggests that replacing sugar with low- or no-calorie sweeteners can reduce calorie and sugar intake. But long-term evidence about their effects on weight, diabetes and cardiovascular disease remains inconclusive.

Erythritol and xylitol deserve particular attention because observational studies and small human experiments have raised questions about cardiovascular risk and platelet activity. A new small preprint failed to reproduce an acute platelet effect, but it doesn't resolve the larger long-term cardiovascular question.

The cancer evidence is also complicated: one large industry-funded review found no consistent association for the sweeteners it examined, while a large prospective cohort found modest associations with cancer for artificial sweeteners, particularly aspartame and acesulfame-K. Neither body of evidence proves causation.

So don't panic.

But don't blindly assume "sugar-free" means "healthy," either.

Read the label. Know which sweetener you're consuming. Pay attention to how much. And when there's a choice, water and unsweetened foods and beverages remain the simplest option.

Sometimes the smartest answer isn't finding a better substitute.

It's needing less of the original thing—and less of the substitute.