Quick answer
The worst offenders for sensitive guts are maltitol and sorbitol — both heavily fermented, both common in "sugar-free," "keto," and "low-carb" products. The good news: they're always labeled (US nutrition law requires "sugar alcohol" + the specific name). Learn the four names to scan for, and you can avoid most of the damage.
This article is one piece of the sugar alcohols and FODMAPs cluster. The hub covers the mechanism.
The four names to know
When you see any of these on a US "Nutrition Facts" label, the product contains a polyol sweetener:
- Sorbitol (E420 in Europe)
- Mannitol (E421)
- Xylitol (E967)
- Maltitol (E965)
- Isomalt (E953)
- Lactitol (E966)
- Erythritol (E968)
US labels can lump these under "sugar alcohol" with total grams. EU labels usually name each one explicitly. If the label just says "sugar alcohol" without naming, you don't know which polyol you're getting, which is information you need to decide.
The ranking from worst to best
Worst offenders first:
Maltitol — about 40% absorbed. Heavily fermented. The single most common cause of severe sugar-alcohol reactions in IBS patients. Hidden in most "sugar-free" protein bars, ice cream, cookies, and chocolate.
Sorbitol — about 50% absorbed. Heavily fermented. Found in "sugar-free" candy, some diet products, and naturally in apples, pears, prunes (which is why these fruits are restricted on low-FODMAP diets).
Isomalt — heavy fermentation, used in hard candies. Less common but a frequent offender when present.
Lactitol — similar to maltitol. Found in baked goods, "no-sugar-added" cookies.
Mannitol — naturally in mushrooms, cauliflower. Less common as an additive.
Xylitol — moderate fermentation, but the small doses in chewing gum rarely trigger.
Erythritol — best tolerated. Most absorbed, least fermented. The only polyol that's safe at typical use for most IBS patients.
Where they hide (the high-risk categories)
Protein bars
- Maltitol is the most common sweetener in mainstream "sugar-free" bars (Quest, Atkins, many store brands).
- Check the label before assuming.
- Better options: bars sweetened with erythritol, stevia, monk fruit, or allulose.
"Sugar-free" candy and chocolate
- Maltitol and sorbitol dominate.
- Often labeled as "no sugar added" — same category.
Keto ice cream, cookies, and baked goods
- Sweetener varies: erythritol in better brands, maltitol or isomalt in cheaper ones.
- Check the actual ingredient list, not the marketing.
Chewing gum and mints
- Xylitol and sorbitol are standard.
- Small doses (1-2g per piece) are usually tolerated even by IBS patients.
"Diabetic" cookies, candy, and baked goods
- Almost always maltitol or sorbitol.
- Often worse than the sugared version for sensitive guts.
Low-carb protein powder
- Some use stevia, monk fruit, or erythritol (good).
- Others use sucralose + maltodextrin, or actual sugar alcohols. Read carefully.
Diet drinks and "zero sugar" beverages
- Most use sucralose or aspartame, not polyols. Less concern here.
- Watch for "natural flavors" and "caramel color" — sometimes hiding FODMAP ingredients.
The label-reading flow
When you pick up a packaged food with a sweetener claim:
- Look at the actual ingredient list, not just the front-of-package marketing.
- Find any of the polyol names listed above. Each one is a flag.
- Estimate the dose — divide the "sugar alcohol" total grams by the serving size. More than 5-10g of maltitol or sorbitol per serving is likely to cause symptoms in IBS patients.
- If unlabeled, the "sugar alcohol" line tells you total grams but not which polyols. In the US, this is allowed but unhelpful. In the EU, look for the explicit E-numbers.
- Decide based on what you found:
- All erythritol → safe for most.
- Only xylitol and small dose → safe.
- Maltitol or sorbitol → avoid or test a small amount first.
- Unlabeled polyols → skip.
The "test it slowly" approach
If you want to test a product that might contain a polyol, do it at home with a small amount and a clear next day free. Most reactions show up within 2-6 hours, but some take 12-24 hours for full effects.
Sample a single serving. If no reaction, you can cautiously add it back to your rotation. If there is a reaction, you have your answer.
The "natural flavors" trap
"Natural flavors" and "artificial flavors" can hide FODMAP ingredients — garlic, onion, fruit concentrates — even if the sweetener is safe. If a product's ingredient list is short and simple, that's a good sign. Long lists with vague terms are warning signs.
When in doubt, look up the product
Apps and resources to check packaged foods:
- Monash FODMAP app — has a product verifier for many common brands.
- FODMAP-friendly app — similar.
- Spoon Guru — barcode-scans and rates products.
Cluster references
This article is part of the sugar alcohols cluster:
- Hub: Sugar Alcohols and FODMAPs: The Complete Guide
- Winner: Sugar Alcohols and Gut Symptoms: What the Evidence Says
- Sibling: Erythritol vs Xylitol: Gut Tolerance Compared
This article is for educational purposes only and isn't medical advice. If you have severe or persistent symptoms, work with a qualified clinician.