Maltitol and stevia are both sugar substitutes, but they differ in several ways. Maltitol is a sugar alcohol with a taste and mouthfeel similar to sugar, while stevia is a natural sweetener derived from the Stevia rebaudiana plant. Stevia is much sweeter than maltitol and has virtually no calories. However, stevia has a distinct aftertaste that some people may find unpleasant. In contrast, maltitol is less sweet than sugar and has fewer calories but a more similar taste profile to sugar.