Sugar alcohols are becoming popular sugar substitutes and are rapidly replacing regular sugar in many keto and low-carb food products. But is sugar alcohol keto? And what is it exactly?
Sugar alcohol is a sugar alternative that contains fewer calories and won’t spike your blood sugar levels.
You may see sugar substitutes like erythritol, xylitol, mannitol, and others on everything from low-carb snacks to protein powders. And most keto experts say that sugar alcohols don’t count toward your total carb count.
When it comes to living a ketogenic lifestyle, the quality of your food is just as important as your macronutrient ratios, especially if fat burning is your goal.
In this guide, you’ll learn about sugar alcohols and how your body process these sugar substitutes. You’ll also discover what they do to your blood sugar and if there are any side effects to consuming them.
What Are Sugar Alcohols?
If you’ve been following a ketogenic diet for a while, then you’ve most likely come across food products containing sugar alcohols.
Also known as polyols, these sugar substitutes are widely used in the food industry to reduce the amount of added sugar in low-carb or low-sugar products.
Sugar alcohol is a bit of a misnomer — they are neither sugar nor alcohol, but a hybrid that creates a whole new type of carbohydrate compound. They also don’t contain ethanol — the chemical in boozy drinks that gives you a buzz.
Sugar alcohols occur naturally in some fruit and vegetables, but the majority are man-made from starch, glucose, and sucrose. They tend to be a bit less sweet than sugar, and often create a cooling effect in your mouth.
For this reason, manufacturers often combine sugar alcohols with either artificial sweeteners or other low-calorie sweeteners to round out their sweet taste[*].
Do Sugar Alcohols Raise Your Blood Glucose?
Here’s a quick review of how blood glucose levels and insulin levels work, and how sugar alcohols may affect them.
How Your Glycemic Response Works
Your glycemic response is the effect that a specific food has on your blood sugar.
While eating a meal rich in sugar will trigger a large glycemic response — aka, sugar in your bloodstream — eating a meal low in sugar and higher in fat and protein will trigger a much smaller glycemic response — less sugar in the blood.
The more blood sugar present, the more insulin you need. Its job is to shuttle that sugar out of your blood and into energy-hungry cells.
If you’re on a low-carb diet or are avoiding sugar because you have diabetes, the main benefit of a low-carb diet is controlling the amount of sugar in your blood and keeping insulin response as low as possible.
How Sugar Alcohols Work
Unlike sugar and sugar-based sweeteners, sugar alcohols are not completely absorbed by your body.
When sugar alcohols reach your small intestine, instead of being rapidly absorbed and entering circulation, they’re only partly absorbed — and very slowly.
The remaining unabsorbed sugar alcohol moves on to your large intestine, never making it into your bloodstream.
While sorbitol is the most likely absorbed, erythritol has the lowest absorption rate[*][*].
Overall, sugar alcohols tend to produce a lower glucose response than fructose, sucrose, or glucose (the most common nutritive forms of sugar).
However, there’s still debate as to whether the number of sugar alcohols used will actually give you a net reduction in calories or not. This is especially dependent on the type of sugar alcohol[*].
Below is the glycemic index for some common sugar alcohols. Of course, the amount you eat and your digestive power also play an important part in how you metabolize them[*].
Note: Low-glycemic is considered anything less than 55.
| Sucrose (table sugar) | 65 |
| Erythritol | 0 |
| Xylitol | 13 |
| Mannitol | 0 |
| Sorbitol | 9 |
| Maltitol | 35 |
| Isomalt | 2 |
Net Carbs in Sugar Alcohol
Since a certain percentage of the sugar alcohols listed on your food items aren’t even absorbed or metabolized, having a strategy in place for when you come across certain sugar alcohols is essential.
Some people choose to count all sugar alcohols as if they were carbs, playing it on the safe side.
If you do choose to subtract sugar alcohols from net carbs, subtract half the amount of sugar alcohols from the total carbohydrate count to get your net carb count[*].
An example would be:
20 grams of total carbohydrate
10 grams of sugar alcohol
Net carb count:
Divide sugar alcohol in half (5) and subtract from total carbohydrate (20) = net carbohydrates (15)
Common Types of Sugar Alcohols
Different sugar alcohols have varying amounts of calories per gram. Some sugar alcohols are sweeter than others when compared to table sugar.
Sorbitol
Sorbitol clocks in at 2.6 calories per gram, with 50-70% sweetness of sucrose. It’s typically used in chewing gum, sugar-free candies, and frozen desserts. It has a cooling effect, without any aftertaste[*][*].
Maltitol
With 2.1 calories per gram and 75% the sweetness of sucrose, maltitol is widely used in hard candies, and can also be found in chewing gum, chocolate, ice cream, and baked goods.
Of all the sugar alcohols, maltitol is the most likely to cause a blood glucose response[*][*].
Xylitol
Xylitol has 2.4 calories per gram and 100% the sweetness of sucrose. Xylitol has been extensively studied for its benefits on oral health[*].
It’s commonly found in chewing gum, toothpaste, mouthwash, as well as hard candy and gum drops[*].
Erythritol
Erythritol has 0.2 calories per gram and 60-80% the sweetness of sucrose, making it a near zero-calorie natural sweetener. It has the least impact on digestive health as it’s not fermented by your gut bacteria[*].
It’s commonly used as a sweetener in low-calorie foods, especially in those products that come from health-conscious manufacturers[*].
Mannitol
Mannitol contains 1.6 calories per gram and has 50-70% the sweetness of sucrose. Mannitol is often used as an ingredient for chocolate-flavored coatings found in ice cream and other confections.
It’s poorly reabsorbed by the kidneys so it may have a diuretic effect[*][*].
Isomalt
Isomalt has 2 calories per gram and has 45-65% sweetness of sucrose. Isomalt is frequently found in toffee, lollipops, cough drops, and wafers[*].
3 Main Health Benefits of Sugar Alcohols
Sugar alcohols offer more than just a healthier stand-in for sugar. Here are some of their health benefits.
#1: Oral Health
One of the biggest culprits in tooth decay and cavities is sugar. When you eat sugar, it reacts with the bacteria in your mouth and creates an acid. This acid acts on your enamel and slowly erodes your pearly whites until they form cavities and collapse.
Xylitol not only replaces sugar, but it also inhibits the growth of harmful bacteria in your mouth. By halting the acid-producing process, xylitol triggers a protective mechanism for oral health[*].
The process of tooth decay and cavities starts with the loss of mineralization and enamel. Xylitol assists in the remineralization of both your enamel and cavities which may have already formed[*].
Erythritol may also have a balancing effect on the bacteria in your mouth, playing a role in the inhibition of cavities[*].
#2: Prebiotic
Prebiotics are a type of carbohydrate that is not fully absorbed in the small intestine. They travel further down your digestive tract and end up in your large intestine, where they can become food for good bacteria.
Since sugar alcohols are only partially absorbed in your digestive tract, they can act as prebiotics to feed the good bacteria in your gut. Xylitol, for instance, has a prebiotic effect and may also contribute to reducing blood glucose, triglyceride, and cholesterol levels[*].
#3: Bone Density
In animal studies, xylitol has been used as a protective measure against bone loss. Although research in humans is lacking, osteoporosis prevention was seen in rats fed a diet consisting of xylitol[*].
In another study, an increase in bone mineral density and bone mineral content was found when rats were fed a continuous and moderate amount of xylitol[*].
3 Possible Downsides of Sugar Alcohols
Sugar alcohols contain plenty of health benefits but might also come with some not-so pleasant side effects.
#1: They May Cause Digestive Issues
Sugar alcohols are only partially absorbed by your body. What doesn’t get taken up by your small intestine gets sent to your large intestine.
Some sugar alcohols are fermented in the large intestine by bacteria. If you eat a large amount of sugar alcohols, you can end up with a lot of gas, digestive discomfort, or even experience laxative effects[*].
Everyone’s body will respond differently to sugar alcohols, but it seems as though maltitol, isomalt, and sorbitol can be the most problematic. All three of these sugar alcohols have been found to cause significant diarrhea and gas[*][*].
Poor absorption of compounds like sugar alcohols in the large intestine can disrupt normal water and electrolyte absorption, ultimately leading to diarrhea.
The fermentation of excessive amounts of sugar alcohols also contributes to creating excessive gas, cramping, and bloating[*].
Erythritol is one sugar alcohol that doesn’t seem to cause much digestive discomfort. The majority of the erythritol you consume actually gets absorbed by your small intestine, and never makes it to the large intestine[*].
Once absorbed, the majority of erythritol remains unmetabolized by your body and gets excreted in your urine. And that small amount that does make it to your large intestine doesn’t get fermented by your gut bugs[*].
#2: They Can Raise Blood Sugar
Maltitol is a disaccharide, meaning it is made of two sugar units bonded together, one of the sugar units being glucose.
When your digestive enzymes get to work on maltitol, the bond is broken and glucose is freed. The small intestine easily absorbs it and therefore it may cause an increase in blood sugar[*].
If your aim is to stay in ketosis, you should definitely avoid maltitol. Even though the blood sugar spike isn’t as large as if you ate pure sugar, it’s not worth the risk of raising insulin.
#3: They May Inhibit Weight Loss
The research available is still quite inconsistent when it comes to sugar alcohols and weight loss.
Since most sugar alcohols need to be used in higher concentrations, there’s a possibility you’ll end up consuming a similar amount of net carbs as standard table sugar[*].
You’re also more likely to indulge in processed snacks if you know they are sugar-free, which can easily lead to overindulgence in foods that don’t support weight loss and overall health[*].
Is Sugar Alcohol Keto?
Keeping blood sugar stable is paramount for a keto diet, but you shouldn’t ignore food quality and the long-term potential effects of things like sugar alcohols.
Although some sugar alcohols won’t necessarily affect your blood sugar, there are still too many unknowns to determine whether or not they are part of a healthy keto diet.
They don’t contain important nutrients and may trigger unwanted digestive issues. More research is needed when it comes to the long-term effects of consistently high doses.
But this doesn’t mean you can’t enjoy some sugar substitutes now and then. In fact, keeping your keto diet exciting is vital to sustaining keto in the long term.
The Takeaway on Sugar Alcohols
Sugar alcohol is a name given to a group of very diverse compounds. Although there are benefits to using sugar alcohols in place of sugar, there are significant downfalls a well.
If you’re still wondering, “Is sugar alcohol keto?” the answer is, it depends. Erythritol is one sugar alcohol that doesn’t seem to spike blood sugar and is also pretty easy on digestion.
Opting for tried-and-true sugar substitutes like stevia and monk fruit is a safe and equally delicious bet.
Read all about these natural sweeteners and discover how to include them in your keto lifestyle: