The market for both is exploding.

According to a report by the market research firm Mintel, sales of stevia were close to $100 million for the year ending July 2009. The company estimates that by the end of 2011, the U.S. ingredient market for stevia could reach $1 billion.

Stevia is extracted from the leaves of a South American herb. Like its counterparts in the blue and pink packets, stevia is calorie-free. (Stevia comes in green or green and white packets). But unlike the others, stevia is a plant-based sweetener, not an artificial one.

In December 2008, the U.S. Food and Drug Administration approved the use of rebaudioside A or reb-A, a derivative of the stevia plant, for use in foods and beverages in the United States, provided it is at least 95 percent pure. Reb-A is 300 times sweeter than sugar.

Stevia sweeteners were launched under the Truvia and PureVia brands and are widely available in supermarkets.

Soft-drink companies were among the first to hop on board, using reb-A, sometimes in combination with sugar, to create drinks that can make the "all-natural" boast, while containing fewer calories. Coca-Cola launched three of its Odwalla juices sweetened with Truvia. PepsiCo partnered with Whole Earth Sweetener Co. to launch the PureVia brand, which Pepsi is using to sweeten its SoBe Lifewater products.

Kelly Reed, a clinical dietitian and coordinator of the diabetes center at Akron General Medical Center, said stevia is appealing because it is derived from a plant, as opposed to being a laboratory creation.

She said many of the diabetics she counsels have discovered Truvia and PureVia since the sweeteners received FDA approval, and most are pleased. Some detractors claim it has a licorice-like aftertaste, but Reed said she hasn't heard any complaints.

In fact, Reed said Truvia is probably as popular as Equal or Splenda among her patients as a sweetener for beverages such as coffee and tea.

Because of its extreme sweetness, Reed cautions users to go easy at first. Both makers claim one packet equals the sweetness of two teaspoons of sugar.

While both Truvia and PureVia offer recipes for desserts using their products, Reed said she expects it will take a while before Splenda is unseated as the baking favorite for non-caloric sweeteners.

Agave nectar is the other natural sweetener that is making a splash in the culinary world. Agave is syrup from the same Mexican plant that gives us tequila. While not calorie-free, it is an all-natural sweetener like honey and boasts a low glycemic index, which makes it a more healthful alternative.

Having a low glycemic index means that agave takes a longer time to convert to glucose in the body, which is good for maintaining steady glucose levels.

However, Reed cautioned that agave is still a sugar, so diabetics need to watch it as carefully as they would sugar, honey or any other carbohydrate.

"It's not great for diabetics," she said, noting that it has roughly the same number of calories and carbohydrates per serving as honey.

Agave nectar comes in three varieties: light, which is a honey-colored syrup; amber, which looks like maple syrup and has a slightly more caramel flavor; and raw, which is similar to amber. All are thinner than honey, but thicker than a simple syrup made from sugar.

Their consistency and natural sweetness are turning heads in the culinary world, particularly in the field of mixology. Cocktail recipes now often call for agave nectar instead of simple syrup.

Agave nectar also is showing up as a substitute for the much-maligned high-fructose corn syrup in products like ketchup and barbecue sauce.

Ania Catalano, a Connecticut-based whole foods chef and author of the 2008 cookbook Baking With Agave Nectar: Over 100 Recipes Using Nature's Ultimate Sweetener ($15.99 Ten Speed Press), said that unlike honey, agave adds sweetness without adding its own flavor.

"Honey is healthy, but everything you make with it tends to taste like honey. . . . The great thing about agave is it is very neutral. It's almost flavorless, and it has a nice clean finish," she said. "It has the advantage of enhancing the flavors of fruits, which is why mixologists have found agave nectar."

Cocktail mixers laced with corn syrup are being shunned in favor of real fruits paired with this natural sweetener.

"It has been a great ingredient because it makes flavors pop. ... It's a natural for a bartender to experiment with it. It has a smooth, clean flavor. The days of mixers made with high fructose corn syrup are just gone," Catalano said.

Agave is available in health-food stores and is working its way into supermarkets. Like honey, it works well for baking and in desserts with a few modifications. Catalano offered the following tips for baking with agave nectar:

—Because of its sweetness, recipes typically require less agave than sugar. As a general rule, replace every cup of sugar with three-quarters of a cup of agave.

—Lower oven temperatures by 25 degrees because agave tends to brown more quickly than sugar.

—Because it is a liquid, the other liquids in a recipe may have to be reduced slightly. This could require a bit of experimentation when attempting to convert a recipe.

—Agave nectar works best for baking when you want a moist product — muffins, cakes, cupcakes. It will actually help baked goods stay fresh longer because it retains moisture.

—Avoid agave if you are looking for a crispy outcome. If you do want to use agave, Catalano suggests experimenting with whole grain flours or combinations of flours to achieve the desired crispy result.

"It is a healthier sweet whose time has come. ... It has a low glycemic index, and the results still taste like gourmet with a wonderful, intense level of sweetness," Catalano said.

Here are two of Catalano's favorite cookie recipes that call for agave nectar:

FLUFFY LEMON BARS

For the crust:

1/4 cup oat flour

1/4 cup barley flour

1 cup raw almonds, ground to a fine meal in a food processor

1/4 cup light agave nectar

1 tsp. ground cinnamon

1 tbsp. canola oil

For the topping:

1 tbsp. unsalted butter, at room temperature

2/3 cup light agave nectar

2 large egg yolks

Juice and freshly grated zest of 2 lemons

1/2 cup barley flour

1 cup evaporated skim milk

3 large egg whites

Preheat the oven to 350 degrees. Lightly oil an 8-by-8-inch baking pan with canola oil spray. To make the crust, mix all the crust ingredients together in bowl. Press the crust mixture into the prepared baking pan and bake for 15 minutes, or until slightly browned. Set aside.

To make the topping, in a large bowl whisk together the butter, agave nectar and egg yolks. Add the lemon juice, lemon zest, flour and evaporated milk. Whisk until well blended. In a separate bowl, beat the egg whites with an electric mixer set on medium speed for 1 to 2 minutes, until stiff (but not dry) peaks form. Gently fold the egg whites into the lemon mixture until combined. Pour the mixture over the prepared crust and bake for 25 to 30 minutes, until the top begins to turn golden and the filling is set. Remove from the oven and cool on a rack completely before cutting into bars.

Store covered in the refrigerator.

Makes 16 2-inch bars.

— "Baking With Agave Nectar: Over 100 Recipes Using Nature's Ultimate Sweetener" by Ania Catalano

OAT 'N' MAPLE CREAM SANDWICH COOKIES

For the cookies:

1/2 cup nonhydrogenated butter substitute (see note)

1 cup light agave nectar

1 tsp. vanilla extract

1/2 cup firm silken tofu, pureed smooth in a food processor

1 cup sprouted spelt flour (see note)

1/2 tsp. baking soda

1/2 tsp. sea salt

1 tsp. ground cinnamon

1/2 tsp. ground cloves

1/2 tsp. ground nutmeg

3 cups regular rolled oats (not quick cooking)

1 cup walnuts, chopped (optional)

1 cup raisins (optional)

For the filling:

1/2 cup nonhydrogenated butter substitute (see note)

1/3 cup plus 1 tbsp. light agave nectar

1/3 cup unsweetened soy milk powder (see note)

1 tsp. vanilla extract

1 tsp. maple extract

Preheat the oven to 350 degrees. Line two baking sheets with parchment paper.

To make the cookies, in a large bowl using an electric mixer set at medium-high speed beat together the butter substitute, agave nectar and vanilla extract until fluffy, about 1 to 2 minutes. Add the pureed tofu and mix until blended well. Add the flour, baking soda, salt, cinnamon, cloves, nutmeg, and oats and stir well. Fold in the walnuts and raisins if using. Drop the batter by heaping tablespoonfuls onto the prepared baking sheets. Using the back of a spoon, flatten slightly and shape into circles. Bake for 12 to 15 minutes, or until lightly golden. Let cool completely on cooling racks.

To make the filling, in a large bowl using an electric mixer set at medium-high speed beat the butter substitute until softened and fluffy, about 1 to 2 minutes. Add the agave nectar and continue to beat well. Add the soy milk powder, vanilla extract and maple extract and beat on high, scraping down the bowl to incorporate all the ingredients. Continue to beat until the filling is light and fluffy.

To fill the cookies, spoon 1 or 2 tablespoonfuls of filling on the bottom (flat side) of one cookie. Top with a second cookie, bottom side on the filling. Wrap individually in plastic wrap and refrigerate for up to 5 days or freeze in plastic freezer bags for up to 3 months, providing you have superhuman willpower.

Makes 1 dozen cookies.

Note: These cookies are vegan. The specialty ingredients in this recipe are available at health or natural food stores.

—"Baking With Agave Nectar: Over 100 Recipes Using Nature's Ultimate Sweetener" by Ania Catalano