Sugar-free candy can fit a keto diet, but it depends on the sweetener. Candies made with erythritol, allulose, stevia or monk fruit have little effect on blood sugar. Those made with maltitol, the most common sweetener in sugar-free chocolate and hard candy, raise blood sugar more and can kick some people out of ketosis. A review of polyols gave maltitol a glycemic index of about 35, compared with 0 for erythritol and 65 for table sugar. Most sugar alcohols can also cause bloating and diarrhea, so eat sugar-free candy in small amounts.
What makes candy “sugar-free”?
“Sugar-free” means the candy has almost no sugar, not that it has no carbohydrate. Most sugar-free candies are sweetened with sugar alcohols (polyols), which are carbohydrates that the body only partly digests. A sugar-free hard candy can list almost as much carbohydrate as a regular one: USDA FoodData Central lists about 98 g of carbohydrate per 100 g for both regular hard candy and a sorbitol-sweetened version. The difference is how much of that carbohydrate your body absorbs.
In the US, the FDA’s label rules include sugar alcohols in “Total Carbohydrate.” In the EU, sugar alcohols are listed separately as polyols, and foods with more than 10% added polyols must carry a laxative warning under EU labeling law.
Sweeteners ranked for keto
Glycemic index (GI) values from a review of polyols, where glucose is 100:
| Sweetener | Glycemic index | Keto-friendly? | Notes |
|---|---|---|---|
| Erythritol | 0 | Yes | Well tolerated in moderate amounts; see the heart note below |
| Mannitol | 0 | Mostly | Often causes digestive upset |
| Lactitol | 6 | Mostly | Laxative in larger amounts |
| Sorbitol | 9 | In small amounts | Common in sugar-free gum and mints; laxative |
| Isomalt | 9 | In small amounts | Used in hard candy |
| Xylitol | 13 | In small amounts | Common in gum; dangerous for dogs |
| Maltitol | 35 | Not really | Raises blood sugar noticeably; very laxative |
| Polyglycitol (maltitol syrup) | 39 | Not really | Found in sugar-free syrups and chocolate |
| Table sugar (for comparison) | 65 | No |
Other sweeteners used in keto candy:
- Allulose is a rare sugar that the body barely uses. The FDA allows US labels to leave it out of “Total Sugars” and “Added Sugars,” and to count it as 0.4 calories per gram.
- Stevia and monk fruit are intensely sweet plant extracts used in tiny amounts. They’re often blended with erythritol.
- Sucralose and aspartame are artificial sweeteners with no meaningful effect on blood sugar.
How to count net carbs from sugar-free candy
Many keto dieters subtract fiber and sugar alcohols from total carbs to get net carbs. That works reasonably well for erythritol and allulose, but not for maltitol, which is partly absorbed. A practical approach:
- Subtract erythritol and allulose fully.
- Subtract only about half of other sugar alcohols, such as maltitol, sorbitol and xylitol.
- Test your own response with a glucose or ketone meter if you’re unsure.
Our guide to calculating net carbs has worked examples.
Side effects to know about
Digestive upset
Most sugar alcohols aren’t fully absorbed, so they reach the large intestine, where they draw in water and are fermented by bacteria. That’s why the EU requires a laxative warning. Maltitol, sorbitol and mannitol are the worst offenders. Erythritol is better tolerated because most of it is absorbed and passed out in urine. Start with one or two pieces and see how you feel.
Erythritol and the heart
A 2023 study in Nature Medicine linked higher blood levels of erythritol with a greater risk of heart attack and stroke in people already being assessed for heart disease, and found that erythritol made platelets more likely to clot in lab tests. It was mainly an observational finding, so it doesn’t prove harm. If you have heart disease or a high risk of blood clots, it’s reasonable to keep erythritol-sweetened foods occasional and ask your doctor.
Weight loss
Sugar-free candy still has calories. Chocolate made with sugar alcohols still contains cocoa butter, and a bar can have as many calories as regular chocolate. Our article on the keto weight loss plateau lists “keto treats” as a common reason weight loss stalls.
Keep it away from dogs
The FDA warns that xylitol, found in some sugar-free gum, mints and sweets, can be poisonous to dogs, even in small amounts. Keep sugar-free products well out of their reach.
The bigger picture
The WHO advises against relying on non-sugar sweeteners for weight control, because the evidence shows no long-term benefit for body fat. Sugar-free candy is a better choice than regular candy on keto, but it’s still a treat. If cravings are frequent, our guide to sugar cravings on keto has strategies that don’t rely on sweets.
Better keto treats
- Dark chocolate with 85% or more cocoa, a square or two at a time.
- Berries with whipped cream or Greek yogurt.
- Homemade treats where you choose the sweetener, such as our keto cheesecake.
- Nuts, especially pecans and macadamias, which taste naturally sweet.
- Sugar-free gum to help with cravings after a meal.
Common questions
Does sugar-free gum break ketosis?
Usually not. A piece of sugar-free gum contains very little sugar alcohol, so one or two pieces won’t affect most people.
Is maltitol keto?
Not really. It has the highest glycemic index of the common sugar alcohols and can raise blood sugar enough to matter on strict keto. It also causes the most digestive upset.
Are “keto” candy bars okay?
Read the label. Some use erythritol, allulose or soluble fiber and fit well. Others use maltitol or have more net carbs than you’d expect.
Is stevia keto?
Yes. Pure stevia extract contains almost no carbohydrate and doesn’t raise blood sugar. Many stevia products are blended with erythritol or with sugars such as dextrose, so check the ingredient list.
Why does sugar-free chocolate upset my stomach?
It’s usually the sugar alcohol, often maltitol. Large amounts draw water into the gut and are fermented by bacteria, causing gas, bloating and diarrhea.
Safety note: Keto isn’t suitable for everyone. If you have diabetes, kidney or liver disease, take regular medication, or are pregnant or breastfeeding, talk to your doctor before cutting carbs this far (why it matters).
This article is general information, not medical advice. Talk to your doctor or a registered dietitian before making big changes to how you eat, especially if you have a health condition, take regular medication, or are pregnant or breastfeeding.
