Maltitol is made from starch, specifically from crops like corn, wheat, or potatoes. The starch goes through a two-step industrial process: first it’s broken down into maltose (a natural sugar), then that maltose is chemically converted into maltitol through a reaction called hydrogenation. The end result is a sugar alcohol that tastes about 90% as sweet as table sugar but delivers fewer calories and a lower blood sugar response.
From Starch to Sweetener
The raw ingredient behind maltitol is ordinary plant starch. Manufacturers typically source it from corn, wheat, or potatoes, depending on regional availability and cost. Starch is a long chain of sugar molecules bonded together, and the first manufacturing step is breaking those chains apart. Enzymes are used to chop the starch into maltose, a simple sugar made of two glucose molecules linked together.
The second step is what transforms maltose into maltitol. In a process called hydrogenation, hydrogen gas is forced into the maltose molecules under high pressure with the help of a metal catalyst. This swaps out a reactive chemical group on the sugar for a more stable one, converting it from a true sugar into a sugar alcohol. It’s the same basic chemistry used to turn liquid vegetable oil into solid margarine, just applied to a sugar molecule instead of a fat. The result is crystalline maltitol, a white powder that looks and behaves remarkably like table sugar.
How Maltitol Compares to Sugar
Maltitol’s popularity comes down to how closely it mimics sucrose. At roughly 90% the sweetness of table sugar, it’s one of the closest sugar alcohol substitutes in taste. Most other sugar alcohols fall well short of that mark, which is why maltitol shows up so often in sugar-free candy, chocolate, baked goods, and chewing gum. It also has similar bulk and texture to sugar, so manufacturers can swap it in without dramatically reformulating a product.
The nutritional differences, though, are meaningful. Maltitol provides 2.4 calories per gram compared to sugar’s 4 calories per gram, a 40% reduction. Its glycemic index sits around 35 to 36 in crystalline form, roughly half of sucrose’s glycemic index of 68. Maltitol syrup, which contains additional hydrogenated sugars, scores higher at about 52. That lower glycemic response means maltitol raises blood sugar more slowly and triggers less insulin release than regular sugar. For context, the insulinemic index of maltitol is 35 versus 45 for sucrose.
These numbers make maltitol a reasonable option for people managing their blood sugar or calorie intake, but it’s worth noting that it’s not a zero-calorie or zero-impact sweetener. Compared to erythritol, which has a glycemic index near zero, maltitol still causes a noticeable blood sugar rise. If you’re counting carbs closely, that distinction matters.
Why It Can Upset Your Stomach
Like all sugar alcohols, maltitol is poorly absorbed in the small intestine. A significant portion of what you eat passes through to the large intestine undigested, where gut bacteria ferment it. That fermentation produces gas, and the unabsorbed maltitol also draws water into the colon through osmotic pressure. The combination can cause bloating, cramping, and diarrhea.
The threshold varies by person, but tolerance studies reviewed by the FDA provide useful benchmarks. Most people can handle up to 30 to 40 grams of maltitol in a single sitting without major issues. Spread across a full day, 35 to 57 grams in divided doses over a week or more tends to be the range where laxative effects start appearing. Above 60 to 70 grams per day, diarrhea occurred in most study participants. Based on these findings, daily amounts up to 30 to 40 grams are generally well tolerated.
The practical problem is that maltitol adds up quickly. A single sugar-free chocolate bar can contain 15 to 20 grams of maltitol, and maltitol is also used in nutritional supplements and other “sugar-free” products you might consume in the same day. If you’re eating multiple maltitol-containing products, you can easily cross that 30-gram line without realizing it.
Where You’ll Find It
Maltitol is one of the most widely used sugar alcohols in the food industry, largely because its sweetness, texture, and melting behavior are so close to sugar’s. It appears in two commercial forms: crystalline maltitol (the powder) and maltitol syrup. The crystalline version is common in hard candies, chocolate coatings, and baked goods. The syrup version works well in chewy candies, ice cream, and soft confections where moisture retention matters.
You’ll spot it on ingredient labels in sugar-free and “no sugar added” products, including candy bars, cookies, protein bars, cough drops, and chewing gum. It’s also used in some pharmaceutical formulations as a sweetening agent. On nutrition labels, maltitol is listed under sugar alcohols, and in many countries products containing it must carry a warning that excessive consumption may have a laxative effect.