Before we get to the new guys on the block, let's take a look at old pink, blue, and yellow. The FDA has given its stamp of approval to saccharin, aspartame, and sucralose. The Center for Science in the Public Interest—a health advocacy group—disagrees about saccharin and aspartame, citing studies that indicate those sweeteners increase the risk of cancer, and advises people to choose sucralose. I don't think it matters which product you choose if you consume less than two artificially sweetened items a day. Or you could ditch artificial sweeteners altogether and switch to one of the new natural sugar substitutes.
Sweeteners based on a sugar alcohol
Erythritol-based products like ZSweet and Zerose have been receiving a lot of buzz lately. Erythritol is a sugar alcohol that occurs naturally in many familiar foods. Unlike other sugar alcohols used in dietetic foods—such as sorbitol, maltitol, and xylitol—erythritol doesn't lead to gassiness or bloating and does not have a laxative effect. Erythritol is 60 percent to 70 percent as sweet as table sugar, so you may need to use more of it in beverages and baked goods. Though made from sugar, the new erythritol sweeteners are calorie-free.
Sweeteners from Stevia –low glycemic(my personal favorite)
PureVia and Truvia are both made from an extract of the stevia plant. Stevia has been consumed for centuries in South America but until recently could be marketed in the U.S. only as a dietary supplement. It was relegated to health-food stores and vitamin shops, where it was sold as a stand-alone sugar substitute. Now that the FDA has approved its use in food, it's only a matter of time before stevia shows up in cookies, cake, candy, and beverages.
Stevia extracts are up to 300 times sweeter than table sugar. They lack some of sugar's physical characteristics, so keep this in mind before you dump a boatload into your coffee or tea. Truvia and PureVia "cut" their products with erythritol, so it's a lot less sweet than pure stevia. Other brands use more concentrated stevia. Recipe and conversion charts can be found online.
Sweeteners from Agave – low glycemic
Products such as Xagave derive from a plant native to Mexico and are sold in syrup form—usually referred to as "nectar." Unlike stevia and erythritol, agave nectar is not calorie-free; in fact, Xagave contains a few more calories than sugar (56 calories per tablespoon of Xagave vs. 50 for sugar). However, Xagave is sweeter than sugar, so you save calories by using less of it. You may need to make other ad-justments when cooking or baking with agave nectar.
Agave's advantage is that it is less likely than sugar to lead to erratic blood-sugar levels. However, if you have irritable bowel syndrome or are at risk for heart disease, you may be better off with stevia, erythritol, or those pink, blue, or yellow packets. Then again, you may prefer to use a small amount of plain old sugar—at only 16 calories per packet.