NEW YORK -- Coke and Pepsi are chasing after the sweet spot: a soda with no calories, no artificial sweeteners and no funny aftertaste.
The world's top soft-drink companies hope that will silence health concerns and reverse the decline in consumption of carbonated drinks. But such a formula could be years away.
The ingredient that makes soda taste good is also what packs on the pounds: high-fructose corn syrup. Artificial sweeteners that are used in diet drinks don't have any calories but are seen as processed and fake. Natural sweeteners that come from plants present the best alternative, but companies haven't figured out how to mask their metallic aftertaste.
"I can't say when it will be here, but it's in the reasonable future," said Al Carey, who heads the beverage unit for the Americas at PepsiCo Inc.
There's good reason soft-drink makers are so eager to tweak their formulas. Sodas are being blamed for the nation's bulging waistlines. That, coupled with the growing variety of flavored waters and sports drinks, has sent per capita soda consumption down 17 percent to about 1.3 cans a day since its peak in 1998, according to data from Beverage Digest, an industry tracker.
In New York City, a ban on sale of sugary drinks bigger than 16 ounces in restaurants, theaters and stadiums could take effect in March. In Richmond, Calif., voters will decide in November whether to pass the nation's first penny-per-ounce tax on soda and other sugary drinks.
Krista Koster, a 29-year-old who lives in Washington D.C., used to down about two cans of soda a day. Now she's trying to kick the habit.
"I've just been hearing how bad soda is," said Koster. "You start considering a lot of the ingredients, whether it's fake sugar or the real sugar."
High-fructose corn syrup has the same nutritional value and taste of sugar. A can of regular soda typically has about 40 grams of high-fructose corn syrup and 140 calories. By comparison, the same amount of apple juice has about 38 grams of sugar and 165 calories, but companies can tout vitamins and other nutrients juice provides.
Aspartame, the artificial sweetener commonly used in drinks such as Diet Coke and Diet Pepsi, doesn't have any calories. But some drinkers worry about the fact that the sweeteners are not natural. Public perception has been colored by past studies that have suggested it caused cancer and brain tumors in rats even though The American Cancer Society says there's no evidence showing it has any link with an increased risk for cancer in adults.
The concerns have led soft drink companies to search for natural, zero-calorie sweeteners, including stevia, which is derived from a South American shrub. Natural sweeteners have neither the calories of sugar nor the negative associations of artificial sweeteners. The trick, however, is figuring out how to make them taste good in colas.
"Every sweetener has its own notes that need to be mixed with other flavors," said Mehmood Khan, chief science officer for PepsiCo. "It's a bit like an orchestra playing music, as opposed to one instrument."
So far, stevia is the natural sweetener that has gotten the most attention and is already used in Coca-Cola and PepsiCo products, including orange juice and bottled teas. But it's proving more difficult to hide the aftertaste in colas.