Coconut sugar, maple syrup, and natural sweeteners are best but these are not as bad as people blaim.NEVER ever use artificial sweeteners such as Sweet n' Low or Splenda.
"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. (Sensitivities vary among individuals.) Erythritol, small amounts of which occur naturally in some fruits, is about 60 to 70 percent as sweet as table sugar and has at most one-twentieth as many calories. Unlike the high-potency sweeteners, erythritol provides the bulk and “mouthfeel” of sugar.
Xylitol: This sugar alcohol, which occurs naturally in birch and some other plants, is about as sweet as table sugar and has about three-quarters of the calories. Too much xylitol (about 30–40 grams or 7–10 teaspoons, although sensitivities vary) could produce a laxative effect and/or gastrointestinal distress.
Stevia leaf extracts: Stevia leaves have long been consumed in Japan, and we rate the extracts made from those leaves as safe, although additional safety tests (particularly long-term tests for cancer) should be conducted. That’s because some short-term tests found that some stevia-related substances caused mutations and other changes in DNA, yet stevia has been tested for cancer in only one species (rat) instead of two species, as usually recommended.
Neotame: We also rate this among the safest sugar substitutes, but taste problems limit its use."
See entire article @ Nutrition Action