Another natural sweetener, stevia, was approved last year by the Food and Drug Administration as "Generally Recognized as Safe" for use in food products, over objections from some food-activist groups such as the Center for Science in the Public Interest.

Stevia is about 100 times sweeter than sugar, although many tasters complain that it has a bitter aftertaste. It comes from a shrub that is grown in Brazil, Paraguay and southeast Asia.

It's also called rebaudioside A or rebiana, and is now marketed under the band names Truvia by Cargill Inc., and PureVia by Merisant Co.

"Because of its intense sweetness and aftertaste, stevia is best used as an enhancement for the likes of oatmeal, stirred into sour beverages, or to add a dash of sweetness to salty and spice preparations," writes Mani Niall in "Sweet!"

"Stevia has no ability to add texture, cream with butter, caramelize or activate yeast, so it takes an intrepid cook to use it as a recipe's major sweetener."