Following a ketogenic diet means drastically reducing your carbohydrate intake to help your body enter ketosis, a metabolic state where fat becomes your primary fuel source instead of glucose. While this requires cutting back on sugar, it doesn’t mean you have to give up sweetness entirely.
Sugar alcohols have emerged as popular sweeteners for people on keto diets. These compounds offer sweetness similar to regular sugar but with fewer calories and a significantly lower impact on blood glucose levels. But are all sugar alcohols created equal when it comes to maintaining ketosis?
This comprehensive guide explores the relationship between sugar alcohols and the ketogenic diet, helping you make informed choices about which sweeteners support your low-carb lifestyle.
What Are Sugar Alcohols?
Sugar alcohols, also known as polyols, are a type of carbohydrate that occur naturally in certain fruits and vegetables. Despite their name, they’re neither sugar nor alcohol in the traditional sense. Instead, their chemical structure resembles both, which is how they got their name.
Most sugar alcohols available today are commercially manufactured through processing starches and sugars. They provide a sweet taste while containing fewer calories than regular sugar—typically about 0.2 to 3 calories per gram compared to sugar’s 4 calories per gram.
What makes sugar alcohols particularly interesting for keto dieters is that the human body cannot fully digest and absorb them. This incomplete absorption means they have a minimal impact on blood sugar and insulin levels, two critical factors for maintaining ketosis.
Common Types of Sugar Alcohols for Keto
Not all sugar alcohols are equally suitable for a ketogenic diet. Here are the most common types you’ll encounter on product labels:
Erythritol
Erythritol is often considered the gold standard for keto dieters. It contains approximately 70% of the sweetness of regular sugar but only about 0.2 calories per gram. What makes erythritol exceptional is its glycemic index of zero, meaning it has virtually no effect on blood sugar levels.
This sugar alcohol is typically produced by fermenting glucose from cornstarch. Its small molecular size allows about 90% of it to be absorbed in the small intestine and excreted unchanged through urine, which means it’s less likely to cause digestive discomfort compared to other sugar alcohols.
Xylitol
Xylitol matches the sweetness of regular sugar while containing about 40% fewer calories. It has a low glycemic index ranging from 7 to 13, making it another excellent choice for keto dieters. Xylitol is commonly used in sugar-free gum, mints, and baked goods.
However, it’s crucial to note that xylitol is extremely toxic to dogs and should be kept away from pets at all times.
Sorbitol
Sorbitol provides about 60% of the sweetness of sugar with roughly 2.6 calories per gram. Its glycemic index of 9 makes it suitable for keto diets when used in moderation. Sorbitol occurs naturally in many fruits and is commonly used in sugar-free candies and chewing gum.
Maltitol
Maltitol is about 90% as sweet as regular sugar and contains roughly 2.1 calories per gram. However, its glycemic index ranges from 35 to 52, which is significantly higher than other sugar alcohols. This higher GI means maltitol can have a more noticeable effect on blood sugar levels, potentially making it less ideal for strict keto dieters.
Isomalt
Isomalt is a mixture of two sugar alcohols and provides about 50% of the sweetness of sugar with approximately half the calories. With a glycemic index of just 2, it’s well-suited for keto diets and is particularly popular in making sugar-free hard candies.
Understanding Glycemic Index and Sugar Alcohols
The glycemic index (GI) is a valuable tool for understanding how different foods affect your blood sugar levels. It ranks foods on a scale from 0 to 100, with pure glucose at 100. Foods with a lower GI cause a slower, more gradual rise in blood sugar.
For comparison, regular table sugar (sucrose) has a glycemic index of 65. Most sugar alcohols have dramatically lower GI values:
- Erythritol: 0
- Isomalt: 2
- Sorbitol: 9
- Xylitol: 7-13
- Maltitol: 35-52
This low glycemic impact is precisely why sugar alcohols are favored by those following ketogenic diets. They allow you to enjoy sweet foods without the blood sugar spike that would kick you out of ketosis.
How Sugar Alcohols Affect Ketosis
Maintaining ketosis requires keeping your carbohydrate intake very low—typically between 20 to 50 grams per day. When you consume regular sugar, it rapidly breaks down into glucose, raising blood sugar levels and triggering insulin release. This process can interrupt ketosis and shift your body back to burning glucose instead of fat.
Sugar alcohols work differently. Because they’re only partially absorbed by the digestive system, they have a much smaller impact on blood glucose and insulin levels. This makes them compatible with ketogenic eating patterns.
Net Carbs and Sugar Alcohols
Many keto dieters use the concept of “net carbs” to track their carbohydrate intake. Net carbs are calculated by subtracting fiber and sugar alcohols from the total carbohydrate count:
Net Carbs = Total Carbs – Fiber – Sugar Alcohols
However, this calculation isn’t perfect for all sugar alcohols. While erythritol can generally be completely subtracted due to its zero glycemic index, maltitol should only be partially subtracted because it has a more significant impact on blood sugar.
A more accurate approach for maltitol is to subtract only half of its grams from your total carb count. For other sugar alcohols like xylitol and sorbitol, you can typically subtract the full amount, though individual responses may vary.
Best Sugar Alcohols for a Keto Diet
If you’re following a ketogenic diet, some sugar alcohols are better choices than others:
Top Choice: Erythritol
Erythritol stands out as the best option for most keto dieters. Its zero glycemic index means it won’t affect your blood sugar or interfere with ketosis. It’s also well-tolerated by most people, causing fewer digestive issues than other sugar alcohols. Erythritol works well in both cooking and baking, making it versatile for various recipes.
Excellent Alternatives: Xylitol and Sorbitol
Both xylitol and sorbitol have very low glycemic indexes and can be used confidently on a keto diet. They’re particularly useful in recipes where you want sweetness that closely matches regular sugar. Just remember to keep xylitol away from pets.
Good Option: Isomalt
With its extremely low GI of 2, isomalt is another solid choice for keto dieters, especially if you’re making candies or want a sugar alcohol that’s less sweet than sugar.
Use Cautiously: Maltitol
While maltitol is commonly found in sugar-free products, its higher glycemic index means it can impact blood sugar more significantly than other sugar alcohols. If you’re trying to stay in deep ketosis or are particularly sensitive to carbohydrates, you may want to limit or avoid maltitol.
Potential Digestive Side Effects
While sugar alcohols are generally safe and well-tolerated, they can cause digestive issues in some people, especially when consumed in large quantities. This happens because they’re not fully absorbed in the small intestine and instead travel to the colon, where gut bacteria ferment them.
Common Side Effects
When consumed in excessive amounts—typically more than 35-40 grams per day—sugar alcohols may cause:
- Bloating and gas
- Abdominal cramping
- Diarrhea
- Nausea
- Stomach rumbling
The severity of these symptoms varies depending on the type of sugar alcohol and individual tolerance levels. Erythritol tends to cause fewer issues because about 90% is absorbed before reaching the colon.
Special Considerations for IBS
Individuals with irritable bowel syndrome (IBS) may be more sensitive to sugar alcohols, even in small amounts. Sugar alcohols are FODMAPs (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols), which can trigger IBS symptoms.
If you have IBS or other digestive sensitivities, you may want to avoid sugar alcohols altogether or introduce them very gradually to assess your tolerance.
Finding Sugar Alcohols in Food Products
Sugar alcohols are widely used in sugar-free and reduced-sugar products marketed to health-conscious consumers and those managing blood sugar. You’ll commonly find them in:
- Sugar-free gum and mints
- Low-carb protein bars and shakes
- Sugar-free candy and chocolate
- Ice cream and frozen desserts labeled “no sugar added”
- Sugar-free syrups and coffee creamers
- Reduced-sugar baked goods
- Sugar-free jams and jellies
- Diet beverages and drink mixes
When reading labels, look for sugar alcohols listed in the ingredients or under “Total Carbohydrate” on the Nutrition Facts panel, where they’re often broken out as a separate line item.
Cooking and Baking with Sugar Alcohols
If you enjoy making your own keto-friendly treats, sugar alcohols can be excellent ingredients for home cooking and baking. However, they don’t always behave exactly like regular sugar.
Tips for Successful Baking
Erythritol is the most popular choice for keto baking, but it can crystallize when cooled and doesn’t caramelize like regular sugar. Blended sweeteners that combine erythritol with other ingredients often perform better in recipes.
Xylitol behaves more like regular sugar in baked goods and can even help with browning. However, it’s hygroscopic, meaning it attracts moisture, which can affect texture.
When substituting sugar alcohols for sugar in recipes, you may need to adjust quantities since some are less sweet than sugar. You might also need to experiment with liquid ratios, as sugar alcohols don’t hold moisture the same way regular sugar does.
Sugar Alcohols vs. Other Keto Sweeteners
Sugar alcohols aren’t the only keto-friendly sweeteners available. Other popular options include:
Stevia
Stevia is a natural, zero-calorie sweetener derived from the stevia plant. It has no impact on blood sugar and is much sweeter than sugar, so you need very little. Some people find stevia has a bitter or licorice-like aftertaste.
Monk Fruit
Monk fruit sweetener is extracted from monk fruit and contains zero calories with no effect on blood sugar. It’s extremely sweet—up to 200 times sweeter than sugar—and is often blended with other ingredients to improve usability.
Allulose
Allulose is technically a rare sugar, not a sugar alcohol, but it functions similarly with minimal impact on blood sugar. It has about 70% of the sweetness of sugar and behaves more like real sugar in baking, including browning and caramelizing.
Many people find that combining different keto sweeteners produces the best taste and texture in recipes.
Practical Tips for Using Sugar Alcohols on Keto
To successfully incorporate sugar alcohols into your ketogenic diet:
Start Slowly
If you’re new to sugar alcohols, introduce them gradually to assess your tolerance and avoid digestive discomfort. Begin with small amounts and increase slowly over time.
Choose Quality Products
Not all sugar-free products are created equal. Some contain fillers or other ingredients that may affect ketosis. Always read labels carefully and choose products with minimal additives.
Monitor Your Response
Everyone responds differently to sugar alcohols. Some people can consume significant amounts without issues, while others are more sensitive. Pay attention to how your body reacts and adjust accordingly.
Stay Hydrated
Since sugar alcohols can have a laxative effect, staying well-hydrated is important, especially if you’re consuming larger amounts.
Don’t Overdo It
Just because something is keto-friendly doesn’t mean you should eat unlimited quantities. Even with sugar alcohols, moderation is key for both digestive comfort and overall diet quality.
Frequently Asked Questions About Sugar Alcohols and Keto
Will sugar alcohols kick me out of ketosis?
Most sugar alcohols have minimal impact on blood sugar and insulin levels, so they’re unlikely to interfere with ketosis when consumed in reasonable amounts. Erythritol is the safest choice, while maltitol may have a more noticeable effect.
Should I count sugar alcohols in my daily carb limit?
This depends on the type. You can generally subtract erythritol completely from total carbs. For other sugar alcohols like xylitol and sorbitol, most people subtract them entirely, but some prefer to count half. Maltitol should be counted at least partially—many experts recommend subtracting only half from total carbs.
Can I use sugar alcohols during intermittent fasting?
This is debated in the fasting community. While sugar alcohols contain minimal calories and don’t significantly spike blood sugar, they may trigger an insulin response in some people. If you’re fasting for autophagy or metabolic benefits, it’s best to avoid all sweeteners. If you’re primarily fasting for ketosis and calorie restriction, small amounts of erythritol are likely fine.
Are sugar alcohols safe for long-term use?
Research suggests that sugar alcohols are safe for most people when consumed in moderate amounts over the long term. However, individual tolerance varies, and some people may experience ongoing digestive issues.
The Bottom Line on Sugar Alcohols and Keto
Sugar alcohols can be valuable tools for anyone following a ketogenic diet who wants to enjoy sweet foods without compromising their metabolic state. They provide sweetness with minimal impact on blood sugar levels, making them suitable alternatives to regular sugar.
However, not all sugar alcohols are equally keto-friendly. Erythritol is the top choice for most people, thanks to its zero glycemic index and good digestibility. Xylitol, sorbitol, and isomalt are also excellent options. Maltitol, while commonly used in sugar-free products, has a higher glycemic index and should be consumed more cautiously.
Remember that individual responses to sugar alcohols vary. What works perfectly for one person might cause digestive distress for another. Start with small amounts, choose high-quality products, and pay attention to how your body responds.
By understanding the different types of sugar alcohols and how they affect your body, you can make informed choices that support both your ketogenic goals and your overall wellbeing. Whether you’re sweetening your morning coffee, baking keto-friendly treats, or choosing sugar-free products at the store, knowing which sugar alcohols work best for your body will help you maintain ketosis while still enjoying the sweetness you crave.
Sources:
- National Institutes of Health – Ketogenic Diet Overview
- PubMed Central – Sugar Alcohols: Chemistry and Applications
- PubMed Central – Glycemic Index of Sugar Alcohols
- PubMed Central – Sugar Alcohols and Digestive Health
- PubMed Central – Understanding Glycemic Index
- PubMed Central – Erythritol: Review of Safety and Health Effects
- PubMed Central – Gastrointestinal Effects of Sugar Alcohols
⚕️ Medical Disclaimer
This content is for informational purposes only and does not constitute medical advice. The information provided has not been evaluated by the Food and Drug Administration (FDA) and is not intended to diagnose, treat, cure, or prevent any disease.
Always consult with a qualified healthcare professional before making any changes to your diet, taking supplements, or starting any health regimen. Individual results may vary.