A key part of following a ketogenic, or keto, diet is reducing your sugar intake. 

This is necessary for your body to enter ketosis, a state in which your body burns fat rather than sugar for energy (1). 

However, that doesn’t mean you can’t enjoy sweet-tasting foods.

Sugar alcohols are sweeteners that have tastes and textures similar to those of sugar, but fewer calories and a less significant effect on blood sugar levels (2). 

As a result, they can be a satisfying option for individuals looking to reduce their sugar intake, such as those following a keto diet.

This article explains whether sugar alcohols are keto-friendly, as well as which ones may be better options for you. 

Common types of sugar alcohols

Sugar alcohols occur naturally in some fruits and vegetables. However, most are commercially manufactured in a lab (2). 

While there are many types of sugar alcohols, common ones you may see on food labels include (3, 4, 5): 

  • Erythritol. Often made by fermenting the glucose found in cornstarch, erythritol has 70% of the sweetness of sugar but 5% of the calories.
  • Isomalt. Isomalt is a mixture of two sugar alcohols — mannitol and sorbitol. Providing 50% fewer calories than sugar, it’s most commonly used to make sugar-free hard candies and 50% as sweet. 
  • Maltitol. Maltitol is processed from the sugar maltose. It’s 90% as sweet as sugar with almost half the calories.
  • Sorbitol. Commercially produced from glucose, sorbitol is 60% as sweet as sugar with about 60% of the calories.
  • Xylitol. One of the most common sugar alcohols, xylitol is as sweet as regular sugar but has 40% fewer calories.

Due to their low calorie contents, sugar alcohols are frequently used to sweeten sugar-free or diet products like gum, yogurts, ice cream, coffee creamers, salad dressings, and protein bars and shakes (2). 

summary

Sugar alcohols are often commercially manufactured as a low calorie way to sweeten food products. Common ones you may see on ingredient lists include erythritol, isomalt, maltitol, sorbitol, and xylitol. 

Glycemic index of sugar alcohols

When you eat sugar, your body breaks it down into smaller molecules. These molecules are then absorbed into your bloodstream, which causes your blood sugar levels to rise (6).

In contrast, your body cannot fully break down and absorb carbs from sugar alcohols. As a result, they cause a much smaller rise in blood sugar levels (7). 

One way to compare the effects of these sweeteners is their glycemic index (GI), which is a measure of how quickly foods can raise your blood sugar (8).

Here are the GI values of common sugar alcohols (4): 

  • Erythritol: 0
  • Isomalt: 2
  • Maltitol: 35–52
  • Sorbitol: 9
  • Xylitol: 7–13

Overall, most sugar alcohols have negligible effects on your blood sugar levels. To compare, white table sugar (sucrose) has a glycemic index of 65 (4). 

summary

Given that your body can’t fully break down sugar alcohols, they cause a much less significant rise in your blood sugar levels than sugar does. 

Sugar alcohols and keto

Sugar intake is limited on a keto diet, as eating it causes your blood sugar levels to rise.

This is an issue, as raised blood sugar levels can make it difficult for your body to remain in ketosis, which is key for reaping the benefits of the keto diet (9, 10).

Given that sugar alcohols have a much less significant effect on blood sugar levels, they’re commonly found in keto-friendly products. 

Furthermore, since they aren’t fully digestible, keto dieters often subtract the sugar alcohols and fiber from the total number of carbs in a food item. The resulting number is referred to as net carbs (11).

Still, due to the variation in GIs of different types of sugar alcohols, some are better for the keto diet than others. 

Erythritol is a good keto-friendly option, as it has a glycemic index of 0 and works well in both cooking and baking. Plus, due to its small particle size, erythritol tends to be better tolerated than other sugar alcohols (12, 13).

Still, xylitol, sorbitol, and isomalt are all suitable on a keto diet. You may simply want to scale back your intake if you notice any gastrointestinal side effects. 

One sugar alcohol that appears to be less keto-friendly is maltitol. 

Maltitol has a lower GI than sugar. However, with a GI of up to 52, it’s likely to have a more significant effect on your blood sugar levels than other sugar alcohols (14, 15). 

As such, if you’re on a keto diet, you may want to limit your intake of maltitol and choose a sugar alternative with a lower GI.

Summary

Given that they negligibly affect blood sugar levels, most sugar alcohols are considered to be keto-friendly. Maltitol has a more pronounced effect on blood sugar and should be limited on a keto diet. 

Digestive concerns

When consumed in normal amounts through food, sugar alcohols are considered safe for most individuals. 

However, they do have the potential to cause digestive issues, especially in larger amounts. Side effects like bloating, nausea, and diarrhea have been observed when intake of sugar alcohols exceeds 35–40 grams per day (13, 16, 17).

Additionally, individuals with irritable bowel syndrome (IBS) may experience negative side effects with any amount of sugar alcohols. As a result, if you have IBS, you may want to avoid sugar alcohol completely (5, 13). 

summary

Consuming large amounts of sugar alcohols may cause digestive side effects, such as diarrhea and nausea. While most people can tolerate small amounts well, those with IBS may want to avoid sugar alcohols altogether. 

The bottom line

Sugar alcohols are low calorie sweeteners that generally have little to no effect on your blood sugar levels. As a result, they’re a popular keto-friendly option for sweetening foods and beverages.

Just keep in mind that some may be better choices than others.

For example, maltitol has a much greater effect on blood sugar levels than erythritol, which has a GI of 0. 

The next time you’re looking to add sweetener to your coffee or make homemade keto-friendly protein bars, try using a sugar alcohol like erythritol or xylitol.

Just be sure to consume these sweeteners in moderation to avoid any potential digestive distress.