Answer: Werther's Original Sugar Free Hard Candies fit the keto diet in moderation.
Each serving of Sugar Free Werther's (5 pieces) contains 1 g of net carbs, though their sweeteners are not ideal. They contain isomalt, which is an iffy sweetener due to its effect on blood sugar.
The primary sweetener in Sugar Free Werther's is isomalt, an artificial sweetener that has a glycemic index of 2. This means that isomalt raises your blood sugar, but the impact is only only 2% of the impact of sugar. Be careful of overconsuming Sugar Free Werther's, as studies have found that people who consume more than 20 g of isomalt in a day are more likely to experience gastrointestinal distress, such as flatulence and diarrhea.
A small number of people have found that isomalt can interfere with their ketosis. If you're not sure whether your body reacts negatively to isomalt, experiment with Sugar Free Werther's in small portions before integrating it into your normal diet.
When it comes to keto-friendly hard candies, the options are pretty thin. Virtually every low-carb or low-sugar candy achieves its low carb count through non-keto sweeteners, like maltitol or sorbitol.
One notable exception is Dr. John's Healthy Sweets Sugar-Free Fruit Hard Candy. Dr. John's uses only keto-friendly sweeteners: erythritol, xylitol, and stevia. Best of all, they're only 1 g of net carbs per serving.
Venturing a bit outside candies, dark chocolate is a classic keto sweet. Varieties that are 80% cacao or higher tend to run between 4 to 6 g of net carbs per serving. Specialty brands like Lily's Chocolate sweeten their chocolate with erythritol, making it even easier to eat on keto.