Two broad groups
- High-intensity sweeteners are many times sweeter than sugar, so tiny amounts are used. Examples: stevia, monk fruit, sucralose, aspartame, acesulfame K, saccharin.
- Sugar alcohols (polyols) are less sweet than or about as sweet as sugar and are used in larger amounts. Examples: erythritol, xylitol, sorbitol, maltitol.
Sweeteners approved for use in food go through safety assessment by national or regional regulators, such as the US Food and Drug Administration (FDA), the European Food Safety Authority (EFSA) and the UK Food Standards Agency. Approval status and permitted uses differ between countries, so the notes below are general.
The common ones at a glance
| Sweetener | Where it comes from | Notes |
|---|---|---|
| Stevia (steviol glycosides) | Purified from the leaves of the stevia plant | Some people notice a bitter or liquorice aftertaste. Highly purified extracts are permitted in the US, EU and UK. |
| Monk fruit (luo han guo) | Extract of a small gourd | Often blended with erythritol. Its permitted use as a sweetener varies by country, so check your local rules. |
| Erythritol | A sugar alcohol, usually made by fermentation | Almost no calories, and less likely than other polyols to upset digestion at normal amounts. Some recent observational research has raised questions about it and cardiovascular risk; that kind of study cannot show cause and effect, and regulators have not changed its approval. |
| Sucralose | Made from sugar by chemical modification | Heat-stable, so it is common in baking blends and drinks. |
| Aspartame | Made from two amino acids | Not heat-stable. Contains phenylalanine, so products must carry a warning for people with the inherited condition phenylketonuria (PKU). |
| Xylitol, sorbitol, maltitol | Sugar alcohols | Used in sugar-free gum and sweets. Xylitol is very toxic to dogs, so keep it out of reach of pets. |
Sugar alcohols and your gut
Sugar alcohols are only partly absorbed in the small intestine. The rest reaches the large intestine, where it can draw in water and be fermented by gut bacteria. In larger amounts this can cause wind, bloating and loose stools. Sensitivity varies widely between people.
In the EU and UK, foods containing more than 10% added polyols must carry the warning "excessive consumption may produce laxative effects". If sugar-free sweets upset you, check for maltitol and sorbitol in particular.
The WHO's 2023 advice on weight control
In May 2023 the World Health Organization published a guideline recommending that non-sugar sweeteners not be used as a means of controlling body weight or reducing the risk of noncommunicable diseases. The WHO described it as a conditional recommendation, based on evidence it judged to be of low certainty. It does not apply to people with existing diabetes, and it is not a statement that sweeteners are unsafe to eat.
The WHO's broader suggestion was to reduce the overall sweetness of the diet over time, which fits the gradual approach on this site.
Aspartame and the 2023 cancer classification
In July 2023 two WHO-linked bodies reviewed aspartame:
- The International Agency for Research on Cancer (IARC) classified aspartame as "possibly carcinogenic to humans" (Group 2B), citing limited evidence. IARC classifies how strong the evidence is that something could cause cancer, not how much risk a normal amount carries.
- The Joint FAO/WHO Expert Committee on Food Additives (JECFA) reviewed the same period of evidence and kept the acceptable daily intake at 0 to 40 mg per kg of body weight.
Put together, the position is that the evidence on cancer is limited and that intake within the established limit is considered acceptable. Regulators such as the FDA said at the time that they disagreed with the IARC classification. If you would rather avoid aspartame, there are plenty of alternatives; if you use it, typical intakes are well below the ADI.
Choosing whether to use them
- A diet drink in place of a sugary one is a reasonable stepping stone for many people. Water or unsweetened drinks are a good end point.
- Sweeteners don't help you get used to less sweetness. If that's your goal, reduce them gradually too.
- "Sugar-free" products can still be high in fat, refined starch or calories. Read the whole label.
- If you have diabetes, ask your care team how sweeteners fit your plan.