Key takeaways
- Sorbitol, maltitol, mannitol, xylitol and erythritol are polyols to recognise in ingredients.
- Polyol type, dose and repeated intakes affect tolerance.
- Presence does not establish quantity or a universal g/h limit.
What are polyols and why are they used?
Polyols are also called sugar alcohols, a name referring to their chemical structure. It does not mean they have the effects of alcohol in alcoholic drinks. Some are used to provide sweetness or contribute to food texture. They can appear in products marketed as containing little sugar, among other foods.
Names to recognise include sorbitol, maltitol, mannitol, xylitol and erythritol. They are not all absorbed in the same way and should not be treated as a single ingredient. The ingredient list identifies which compound is present, giving more precise information than an assessment based only on product category.
A ‘sugar-free’ product is not necessarily free from polyols, and the claim does not describe its complete energy contribution. For exercise, read ingredients and available nutrition information. Polyols should not be treated as replacements for the carbohydrate sources commonly used to support endurance, such as glucose, maltodextrin or glucose–fructose combinations.
Why can they cause symptoms?
Some polyols are incompletely absorbed in the intestine. The portion remaining in the digestive tract can draw in water and be fermented by intestinal bacteria. These mechanisms may contribute to gas, bloating, abdominal pain or diarrhoea. They explain a digestive consideration without predicting symptoms in every person who consumes a product.
Amount matters, along with repeated intakes and other foods. Experience with a small serving at rest does not necessarily describe several servings during a long race. The same product can represent different amounts when you eat a serving, a whole pack or several packs. Keep the actual amount consumed in view.
If discomfort occurs, avoid immediately concluding that one ingredient caused it. Intensity, heat, total volume and other ingredients may have changed. Record the product, servings and circumstances. That description makes the next trial more useful than simply labelling a whole ingredient family ‘well tolerated’ or ‘poorly tolerated’.
Why erythritol is a particular case
Erythritol, also identified as E 968, is largely absorbed and then excreted in urine. Its behaviour differs from less well-absorbed polyols. However, EFSA confirmed in 2023 that substantial quantities can cause diarrhoea. Greater absorption therefore does not justify promising an absence of digestive effects.[1]
Distinguish a general food-additive evaluation from an exercise recommendation. Values used in a food safety assessment do not automatically become hourly limits for a race. Dividing them by exercise duration would produce a seemingly precise number without establishing that it is suitable or validated for that use.
The polyol’s name is therefore one piece of information when choosing a product. Available quantity, serving size and your experience complete the picture. If erythritol appears without a declared amount, you know it is in the recipe; you cannot conclude that its dose is low, high or guaranteed to be comfortable.
Understand the difference between polyols and FODMAPs
FODMAP describes a family of fermentable carbohydrates including some polyols and other compounds. A study of a low-FODMAP diet therefore changes several food sources. It is not automatically a study of one particular polyol contained in a gel or bar. Keep that distinction when interpreting a headline or recommendation.
A 2019 trial in sixteen runners observed fewer symptoms after a short period of low-FODMAP eating. Outcomes included reported symptoms and did not establish an improvement in measured race performance. The findings also cannot attribute the entire change to polyols alone.[2]
These results may inform decisions for sensitive athletes without justifying systematic exclusion for everyone. Broad restriction can make food choice and maintaining intake more difficult. This guide’s practical subject is reading products consumed during exercise, rather than prescribing a lasting elimination diet or treating every FODMAP as a problem.
Identify them on a label
First look for names in the ingredient list. Then check whether a polyol quantity is declared in the nutrition information. Presence and quantity are different data. Ingredient order cannot calculate grams per serving, and sweetness does not measure the dose. A clearly named ingredient can still have an unknown quantity.
Always check the reference basis: per 100 g, per serving or per whole product. Where a quantity is declared, adjust it to the serving actually eaten. If several polyols are used, a total value may not describe how much of each is present. Keep that limitation visible when comparing products.
An undeclared quantity must remain unknown. Writing 0 g because the label entry is missing would make the product artificially easier to interpret. You can still note ingredients and compare other contributions, but you do not have all the information needed for a dose calculation or an hourly total.
Choose products for repeated intakes
Choosing products low in polyols can be a practical precaution, particularly with digestive sensitivity or repeated intakes over several hours. This does not mean every product containing a polyol will cause a problem. Caution should remain proportionate to what you know about the recipe and your own experience with it.
Test the intended serving, then consider repeated intakes in representative conditions. Record drinks and other foods too. One product cannot describe your entire consumption. When comparing trials, avoid changing serving sizes, carbohydrate intake, drinks and pace all at once, since that makes the experience harder to interpret.
Finally, check that the food continues to serve its intended exercise role. A choice based only on ‘sugar-free’ marketing can overlook the carbohydrate contribution you wanted. Consider what you will actually consume and what still needs to come from other sources. Comfort and the ability to maintain intake need to be considered together.
Label example: presence and quantity
Fictional teaching example: a bar’s ingredient list mentions maltitol but no polyol amount is declared. You can identify its presence. You cannot calculate g/h from that information alone.
In another example, a serving declares 3 g of polyols. Two servings provide 6 g in total. This describes the intakes, not a recommended dose or a universal symptom threshold. The type of polyol and the circumstances still matter.
Frequently asked questions
Does sugar-free mean polyol-free?
No. Some products use polyols to provide sweetness. Read ingredients and available quantities instead of inferring their absence from a front-of-pack claim. The claim also does not describe the complete nutritional contribution of the product.
Is erythritol always well tolerated?
No. Its absorption differs from other polyols, but substantial amounts can still cause symptoms. Its presence alone cannot guarantee a product’s tolerance, particularly with repeated servings. The quantity and your experience remain relevant.
Should you follow a low-FODMAP diet?
Not systematically. Athletic research examines approaches broader than polyols alone and finds variable responses. A global restriction should not follow from reading one product. Recurrent difficulties deserve individual consideration rather than an automatic elimination of whole food groups.
How Glyk considers this topic
Glyk considers polyols in its estimated digestibility assessment during exercise, using the available information. Identified presence must not be confused with a known quantity.
This interpretation helps identify a consideration and compare products. It does not predict your digestive response. The guide’s references provide scientific context without turning the application’s rubric into a clinical consumption limit.
Scientific sources
These references inform the guide. Published recommendations, study findings and their interpretation in Glyk remain distinct. They do not validate the application’s scoring rubric.
