Sweeteners are available in powder and liquid form, and are primarily used for replacing sugar. Like sugar, sweeteners provide a sweet taste, but what sets them apart is that, after consumption, they do not increase blood sugar levels. The best and safest sugar substitutes are erythritol, xylitol, stevia leaf extracts, and neotame—with some caveats: Erythritol: Large amounts (more than about 40 or 50 grams or 10 or 12 teaspoons) of this sugar alcohol sometimes cause nausea, but smaller amounts are fine.