If you haven't heard of agave nectar or stevia, chances are you will before the year is over. The two sweeteners are showing up in cocktails, bottled drinks and a host of other products.

If you haven't heard of agave nectar or stevia, chances are you will before the year is over. The two sweeteners are showing up in cocktails, bottled drinks and a host of other products.

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 noncaloric 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."

Agave is available in health-food stores and has worked 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.