Food and drink

Are artificial sweeteners worse for you than sugar?

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In trials, swapping sugary drinks for low- or no-calorie sweetened drinks helped weight a little. The adults had overweight or obesity and were at risk for or had diabetes. Long-term health effects remain unclear: adult studies link higher sweetener use with disease but do not show cause.

“They make you gain weight”

A 2022 review covered trials that assigned drinks by chance. It found about 1 kg lower weight when low- or no-calorie sweetened drinks replaced sugary drinks. The adults had overweight or obesity and were at risk for or had diabetes. Certainty was moderate. The review's median follow-up was 12 weeks. WHO reported that a few 6–18-month adult trials did not suggest a weight effect. But differences in their methods and reporting made the findings hard to interpret.

In adults with overweight or obesity, the 2025 SWEET trial compared sweetener products with its sugar-group diet. The sweetener group kept off 1.6 kg more weight at one year. Both diets limited added sugar. That main analysis included only 277 adults. They had lost at least 5% of their weight by month 2. When a one-year weight was missing, the analysis used that person's last recorded weight. Among the 203 adults who finished, the difference was similar but was not statistically significant.

“They cause diabetes and heart disease”

Long-term observational studies followed adults without telling them how much sweetener to consume. They linked higher non-sugar-sweetener intake with increased risks of type 2 diabetes, cardiovascular disease and death. WHO rated this evidence very low to low certainty. One possible explanation is that people already at higher risk switch to sweeteners. Even a large French study that tried to account for this could not rule it out.

“They cause cancer”

Long-term studies followed adults without telling them how much sweetener to consume. Higher non-sugar-sweetener intake was not associated with overall rates of new cancer cases or cancer deaths. WHO rated this evidence very low certainty. Separate adult case–control studies assessed cancer risk. They linked sweetener use, mainly saccharin, with increased bladder-cancer risk. Certainty was also very low.

“They upset your stomach”

A separate group of sweeteners, sugar alcohols, includes erythritol and sorbitol. A review found that sugar alcohols can cause gas, discomfort and laxative effects. These effects depend on the amount consumed; the review also identifies the type of sugar alcohol as a likely factor. During adult weight maintenance, SWEET's sweetener-products group reported more digestive health problems than the sugar group. The trial allowed intense sweeteners, sugar alcohols, slowly digestible carbohydrates and sweet fibres. It remains unclear which ingredient was responsible.

Official positions, with dates

WHO, 15 May 2023: conditionally advises against using non-sugar sweeteners for weight control or reducing the risk of noncommunicable diseases. This excludes people with existing diabetes and sugar alcohols. It does not replace safety assessments.

FDA, 27 February 2025: authorized sweeteners are safe for the general population under specified conditions of use.

IARC/JECFA, 14 July 2023: IARC called aspartame possibly cancer-causing on limited evidence. JECFA kept its daily safe-intake limit. The classification describes the strength of evidence that an agent can cause cancer in humans. It does not describe the risk at a particular dose.

EFSA, 20 December 2023: set erythritol's daily acceptable intake at 0.5 g per kg of body weight. This was to protect against diarrhoea and its consequences. Estimated acute and chronic erythritol exposure exceeded this limit in all population groups assessed. But uncertainties likely made those estimates too high.

EFSA, 16 February 2026: kept sucralose's daily acceptable intake. Estimated current EU exposure was below it. EFSA could not confirm the safety of a proposed extension to sucralose's use in fine bakery wares. There was uncertainty about chlorine transfer during prolonged high-temperature heating of sucralose. This uncertainty also applies to home baking or frying.

What people also ask

Which is worse, real sugar or artificial sweeteners?

The outcome matters. Trials support modest weight benefits when low- or no-calorie sweetened drinks replace sugary drinks. Those trials studied adults with overweight or obesity who were at risk for or had diabetes. Long-term disease effects remain uncertain.

What does cutting out artificial sweeteners do to your body?

For sugar alcohols, digestive effects depend on dose. A five-week trial mainly tested sucralose. It found that the share reporting diarrhoea increased within the sweetener-containing group. But sugar, fibre and fasting were uncontrolled, and the trial lost participants. This limits conclusions about cutting sweeteners out.

Which artificial sweeteners should I avoid?

FDA specifically says people with phenylketonuria, a rare genetic disorder that makes it difficult to process phenylalanine, should avoid or restrict aspartame.

Can artificial sweeteners cause diarrhea?

Yes for sugar alcohols: effects depend on dose. EFSA keeps erythritol's excessive-consumption laxative warning.

What people think

The disease links deserve attention. An online survey of views on artificial sweeteners included 386 Saudi adults. The group most concerned about sweetener risks also showed the strongest preference for natural foods. The researchers suggest this preference for natural foods may reflect concerns about processing and artificial ingredients. The researchers offered this as a possible explanation based on a sample chosen for convenience. The convenience sample limits how far the findings apply to Saudi adults overall.

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