Why Sugar Alcohols Can Give You a Stomach Ache (And What We Use Instead)

Forty-five minutes after the bag of sugar-free gummies, your stomach starts making its opinion known. First comes the cramping, then the bloating, then the embarrassing part nobody wants to discuss over lunch.

You probably ate the gummies because they seemed like the sensible choice. Fewer calories, no added sugar, maybe you could have a few more. Then the maltitol or sorbitol catches up with you. Your small intestine leaves some of it behind, and by the time it reaches the colon, your gut bacteria have plenty to work with.

What happens in your gut

Sugar alcohols save calories because the small intestine does not absorb all of them. A 1990 study in Gastroenterology measured this with sorbitol and maltitol. About 79% of pure sorbitol was absorbed before it left the small intestine. When the sorbitol came from maltitol, which the body first breaks down into glucose and sorbitol, absorption dropped to about 64%.

The rest keeps moving into the colon, where gut bacteria ferment it. Fermentation produces gas, while the unabsorbed sugar alcohol draws water into the intestine through osmosis. Put those together and you have a fairly predictable afternoon: cramping, bloating, and an urgent search for a bathroom. The trouble starts with an ingredient your small intestine can only partially absorb, and your colon takes on a large burden.

Erythritol is a little different

Erythritol gets mentioned alongside sorbitol and maltitol all the time, although your body handles it quite differently. About 90% is absorbed in the small intestine, and roughly 80–90% of what you eat leaves the body unchanged in urine within a day. Very little reaches the colon for fermentation, which is a big part of the reason erythritol became so popular in keto snacks.

There is also an ongoing question about erythritol and cardiovascular health. A 2023 study from the Cleveland Clinic, published in Nature Medicine, found that people with elevated blood erythritol had roughly twice the risk of a major cardiovascular event over three years in a group of patients already at elevated cardiac risk. There is an important wrinkle, though: your body makes erythritol on its own during glucose metabolism, so blood erythritol does not come entirely from food. A 2023 critique in Frontiers in Nutrition pointed out that the study could not determine how much of the measured erythritol came from diet.

The researchers themselves said a dietary-intake trial would be needed to establish whether eating erythritol drives the cardiovascular risk they observed. That question is separate from the stomach ache you get after eating maltitol or sorbitol. Digestive symptoms come from what reaches the intestine; the erythritol cardiovascular question involves blood levels and remains an area of research.

Why dose matters

Sugar alcohols become more interesting as the amount goes up, and the numbers vary quite a bit depending on the compound and the person. The FDA's 2021 labeling guidance calls for a "may have a laxative effect" warning when expected daily intake reaches 50 grams of sorbitol or 20 grams of mannitol. Individual foods also need a warning when they contain more than 10 grams of maltitol per 100 grams or more than 25 grams of sorbitol per 100 grams.

People with IBS can be more sensitive. Monash University's FODMAP research program found that a single 10-gram dose of sorbitol or mannitol increased GI symptoms in people with IBS compared with healthy controls.

That matters with candy because candy is easy to keep eating. You grab a bag, watch a movie, reach in again, and eventually you've eaten considerably more than the serving size printed on the back. Sugar-free candy can make that especially easy because the calorie count looks better. Then, about forty-five minutes later, your digestive system has to deal with this burden.

Why we use beet sugar

Pac Pac uses beet sugar instead of sugar alcohols. There is a calorie tradeoff: sucrose provides about 4 calories per gram, while maltitol provides roughly 2.1 calories per gram and is about 90% as sweet as sucrose. That combination helps explain why maltitol shows up in so much sugar-free candy.

You can see how that plays out on real labels. A two-piece serving of Russell Stover's maltitol-sweetened sugar-free chocolate lists 130 calories, or about 65 calories per piece. A Pac Pac chew has about 15–20 calories and 4 grams of sugar. Chocolate is a somewhat unfair comparison because it is more calorie-dense than a jelly chew, while sugar-free gummies tend to land closer to 40–70 calories per serving, but the basic point holds: swapping sugar for maltitol does not automatically make every piece of candy lower in calories.

The bigger reason we use beet sugar is what happens after you eat it. Sucrose is sugar, so your small intestine absorbs it and breaks it down into glucose and fructose. Beet sugar and cane sugar are almost identical by the time they reach the package: both are refined to more than 99.95% sucrose, both provide about 30 calories per 8-gram serving, and both have a glycemic index around 65.

The two sugars spend their early lives in different crops and different fields, but by the time they have been refined and made it into a bag of candy, there is very little left to distinguish them nutritionally. We use beet sugar for sourcing reasons. Your digestive system treats it much the same way it treats cane sugar.

What about the glucomannan?

There is an obvious question here. Pac Pac chews are made with konjac glucomannan, a soluble fiber, and fiber reaches the colon too, where gut bacteria ferment it. So why does glucomannan behave differently?

The amount makes a big difference. Clinical glucomannan supplements are often taken at around 2–4 grams per day, and digestive side effects become more likely around 3–4 grams. Those are supplement-sized doses, considerably larger than the amount of glucomannan in a Pac Pac chew. The amount you eat matters as much here as it does with any other fermentable carbohydrate.

Then there is the physical character of glucomannan. It is a long, water-loving fiber that swells and forms a thick gel when it meets water. You can see that behavior in the chew itself: konjac gives the jelly its firm, springy texture. In your digestive tract, that same tendency to absorb water means glucomannan moves through as a viscous gel rather than behaving like a small sugar molecule dissolved in liquid.

A 2012 in vitro study compared konjac glucomannan with several other fibers over 8–24 hours and found that konjac glucomannan produced less gas than inulin, a fiber that ferments more readily.

Glucomannan can still cause bloating. People respond differently, and higher doses are more likely to cause digestive symptoms. The available studies also vary too much to give you a useful percentage. The simple answer is that some people get bloated from glucomannan, especially at higher doses, and the amount in a Pac Pac chew is much lower than the doses used in studies of glucomannan supplements.

New to konjac? Our guide to what konjac candy is covers the plant and the texture from the start.