The Short Answer
Sugar alcohols are low-calorie sweeteners added to protein bars and snacks to hit a lower net-carb count without using real sugar. While they're generally recognized as safe, they're poorly absorbed by the small intestine — which means bloating, gas, and GI distress are common side effects, especially with repeated consumption. If your protein bar's ingredient list ends in -ol, that's your first red flag.
What Are Sugar Alcohols, Actually?
Despite the name, sugar alcohols are neither sugar nor alcohol in the way most people use those words. They're a class of carbohydrate — chemically called polyols — that occur naturally in small amounts in some fruits but are manufactured at scale for use in processed food.
Common sugar alcohols you'll find on protein bar labels:
- Maltitol — the most frequently used and arguably the worst offender for GI symptoms
- Sorbitol — a known laxative at higher doses
- Xylitol — better tolerated by most, still causes issues in volume
- Erythritol — the most gut-friendly of the group, but not without debate
- Isomalt, Lactitol, Mannitol — less common but still present in some bars
Food manufacturers use them because they register lower on glycemic index tests than table sugar and can be partially subtracted from total carbs when calculating "net carbs." That makes macros look cleaner on paper.
The problem is your gut doesn't read the label.
Why Sugar Alcohols Cause Digestive Problems
Here's the core issue: most sugar alcohols aren't fully absorbed in the small intestine. They pass into the large intestine mostly intact, where gut bacteria ferment them. That fermentation produces gas — and depending on how much you've consumed and how sensitive your digestive system is, the results range from uncomfortable to genuinely disruptive.
The Osmotic Effect
Sugar alcohols also pull water into the colon through osmosis. That's the mechanism behind their well-documented laxative effect. Maltitol and sorbitol are particularly aggressive here. Some studies have shown that as little as 10–15 grams of maltitol can cause loose stools in sensitive individuals — and many protein bars contain that much or more in a single serving.
Cumulative Load Matters
If you're eating one bar a day — which is exactly the use case protein bars are designed for — you're hitting that gut load consistently. One bar might not level you. Three bars across a week, plus other "sugar-free" foods also sweetened with polyols, and you've quietly stacked a significant digestive burden.
This is a real concern for former athletes and active adults who are using protein bars as a genuine nutrition tool, not an occasional treat.
How to Read a Label for Sugar Alcohols
Manufacturers aren't required to list sugar alcohols separately in all cases, though many do — often under the carbohydrate section as a line item. Here's how to find them:
- Check the ingredients list first. Anything ending in -ol (maltitol, sorbitol, xylitol, erythritol, mannitol, isomalt) is a sugar alcohol.
- Look at the nutrition facts panel. Some labels will show a "Sugar Alcohols" sub-line under Total Carbohydrates.
- Do the net carb math yourself. Brands subtract sugar alcohols from total carbs to arrive at net carbs. That number can be misleading — maltitol in particular still has a meaningful glycemic impact despite being subtracted out.
- Don't trust "no added sugar" as a proxy for clean. That claim only means sucrose wasn't added. Sugar alcohols or artificial sweeteners may still be in the formula.
If you want to go deeper on how to identify and compare cleaner options, we broke this down further in our guide to [protein bars without sugar alcohols](/blog/protein-bars-without-sugar-alcohols).
Who Should Be Most Careful
Sugar alcohols aren't dangerous for most people in small amounts. But there are groups for whom consistent exposure is more likely to cause real problems:
- IBS or IBD sufferers — polyols are explicitly flagged as high-FODMAP foods, which are known triggers for these conditions
- People with sensitive digestive systems — the threshold for symptoms varies widely by individual
- High-volume snackers — if you're eating multiple "protein snacks" a day, sugar alcohol accumulation is a real factor
- Athletes in-season or pre-competition — the last thing you want during a training block is unpredictable GI distress from your recovery snack
The "Net Carb" Marketing Trap
This deserves its own section because it's the primary reason sugar alcohols are in so many bars to begin with.
The net carb calculation — total carbs minus fiber minus sugar alcohols — is a marketing construct, not a regulated FDA definition. Brands use it to display a number that appeals to low-carb and keto shoppers. The issue is that not all sugar alcohols behave the same way metabolically. Maltitol, the cheapest and most common one, has a glycemic index of around 35 — well above erythritol (near 0) and meaningful enough to affect blood sugar in real-world consumption.
So you might buy a bar that advertises "4g net carbs" and contains 25 grams of total carbs, most of which is maltitol. The advertised number is technically accurate under current labeling conventions. The lived experience may be different.
What to Look for Instead
The simplest filter: buy bars where you recognize every ingredient. If the sweetness comes from real fruit, honey, or dates — things that exist in nature without a manufacturing plant — you know what you're dealing with.
At Genesee, we built our bars around that same logic. No sugar alcohols. No artificial sweeteners. No seed oils. Whole-food ingredients anchored by grass-fed bison tallow — a fat source former athletes on our founding team actually believed in and couldn't find anywhere else on shelves.
The bars carry 21 grams of protein and are formulated for people who read labels and know the difference between a number that looks good and an ingredient list that is good. You can see exactly what's in them on our [product page](/products), or read more about why we built the brand this way on [our story](/our-story).
We're not going to tell you every other bar is trash. We will say that if "no sugar alcohols" is on your checklist — and after reading this, it probably should be — it shouldn't be hard to find that on our label.
If you're evaluating your current bar against ours, our [comparison page](/compare/genesee-vs-prima) lays out the differences directly.
The Bottom Line
Sugar alcohols are a cost-effective way for manufacturers to lower net carb counts and avoid adding real sugar. For a segment of consumers — especially those eating bars daily or those with digestive sensitivities — the tradeoff isn't worth it. Bloating, gas, and loose stools are common enough side effects that the FDA requires a warning label on products containing sorbitol above a certain threshold.
Read the -ol endings. Do the math on the full carbohydrate panel. And when in doubt, buy bars made from ingredients you'd actually recognize in a kitchen.
If you want to try bars without any of that noise, [geneseenutrition.com/products](/products) is a good place to start — subscription options available if you want to make it a habit without the weekly reorder.