ccasionally, someone will ask why their low carb diet isn’t working as they think it should be. One of the first questions I ask is whether they are eating products with a lot of sugar alcohols such as maltitol. Although it doesn’t have the same impact on every individual, this one ingredient has been known to stall many a well-intentioned dieter. Here’s why.


Maltitol is a sugar alcohol, an ingredient commonly used in low carb or “sugar-free” products such as candy and nutrition bars. It is used so much because of its similarity to sugar in terms of taste, mouthfeel, and interaction with other ingredients. Products which use maltitol and other sugar alcohols as sweeteners can be called “sugar-free.” Although claims are often made that maltitol has little impact on blood sugar, this turns out not to be the case.


Maltitol is a carbohydrate. Although our bodies do not absorb all the calories in maltitol, this substance does provide us with 2 to 3 calories per gram, compared to the 4 calories per gram of sugar. (For what its worth I have noticed that the claim of 2 calories per gram usually comes from literature provided by the manufacturer or the low calorie food industry whereas other analyses tend to be closer to 3 calories.) Since maltitol is a carbohydrate, and since it provides calories, you would expect it to impact blood glucose. You would be correct.


In particular, maltitol syrup has a glycemic index of 52, which approaches that of table sugar at 60. The powdered form has a glycemic index of 36, which is still higher than most other sugar alcohols and all artificial sweeteners.


Estimates run from 75 to 90 percent of the sweetness of sugar. Again, the information provided by industry groups tends to give the 90% figure, while other sources say 75 percent. So, if maltitol has ¾ of the sweetness of sugar, ¾ the calories of sugar, and ¾ the glycemic index of sugar, it isn’t a far leap to the conclusion that you need ¼ more maltitol to get the same effect of sugar –which will give you close to the same effect in most other ways (except for dental cavities). You are basically getting very expensive sugar. And…a bonus:


Usually this takes the form of intestinal gas and cramping, but some people may find themselves with diarrhea. If you decide to eat products with maltitol, you’d be wise to start with a small amount and judge the reaction -- as well whether you’ll be in a crowded room a few hours later.


The best alternatives to products with maltitol are usually made with erythritol, often in combination with artificial sweeteners such as sucralose (Splenda). But almost any other sugar alcohol is at least a little better than maltitol (see chart at the bottom of this article about sugar alcohols.