Rob Hobson is a registered nutritionist and author of  The Detox Kitchen Bible as well as head of nutrition at Healthspan. Here, he answers a question about sugar substitutes known as sugar alcohols.

Q: I know sugar alcohols, such as xylitol and erythritol, don’t raise your blood sugar but these sugar substitutes make me so gassy! Do you know why this is?

Sugar alcohols, such as xylitol, sorbitol, maltitol and erythritol are commonly used in foods as a way of eliminating the use of added sugars.

A diet high in added sugars is associated with an increased risk of weight gain and obesity, which in turn are risk factors for many other health conditions, such as heart disease.

Artificial sweeteners get bad press, but much of this negativity tends to be based on very high intakes. Sugar alcohols may help feed bacteria in your gut by way of a prebiotic effect – shifting the microbiome towards an increase in gut-friendly bifidobacterium, which is a good thing.

However, in some people, these artificial sweeteners may result in unwanted side effects, such as excessive gas, bloating, diarrhoea, and other digestive issues.

Take note if you have IBS

Sugar alcohols are not fully digested or absorbed in the body and this may be a particular issue for those suffering from gut conditions such as IBS.

Another name for sugar alcohols is polyols, which is part of the FODMAPs acronym (fermentable oligosaccharides, disaccharides, monosaccharides and polyols) and represent food components that trigger symptoms.

Don’t have too much

The negative effects of sugar alcohols are likely to be linked to quantity, so try to avoid having large amounts in one go.

If you have IBS, you may have to avoid sugar alcohols altogether. Research has shown that xylitol and erythritol appear to cause fewer symptoms than maltitol and sorbitol, so check the ingredient list when choosing low-sugar food products.

Rob Hobson ( is the co-author of The Detox Kitchen Bible (£14.99, Bloomsbury)

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