The world's No. 2 soda company says that Pepsi Next in Australia has 30% fewer calories than regular. A representative for the company did not immediately know what other sweeteners are used in the drink.

The rollout follows the launch of Pepsi Next in the U.S. earlier this year. The U.S. version, however, uses a mix of artificial sweeteners and high fructose corn syrup. It also has about half the calories of regular, at 60 calories per can.

Pepsi Next was developed to win back lapsed soda drinkers who want to cut back on calories but don't like the taste of diet soda. The Coca-Cola Co. this summer also began testing reduced-calorie versions of its Sprite and Fanta that use a mix of sugar and natural sweeteners such as stevia, which is derived from a South American shrub.

The moves by Coke and Pepsi come as per capita soda consumption in the U.S. has declined over the years. Now the companies are trying to come up with formulas that address concerns about calories and artificial sweeteners, without sacrificing taste.

The challenge is that zero-calorie natural sweeteners like stevia often have a bitter aftertaste that's difficult to mask in sodas.

It's not the first time the companies have taken a stab at mid-calorie sodas. In 2001, Coke rolled out "C2" and Pepsi in 2004 introduced its "Pepsi Edge," both of which had about half the calories of regular. Both were taken off the market by 2006 because of poor sales.