The role that added sugars play in the obesity epidemic has been the subject of heated debate by scientists worldwide, from the World Health Organization to the recent meeting of the U.S. Dietary Guidelines Advisory Committee.

While researchers, politicians and the food industry argue over the waistline impact of consuming soft drinks, candy and other popular foods with added sweeteners, there is, of course, another option: sugar substitutes.

Some 80 percent of adults -- 163 million Americans -- use low-calorie and sugar-free foods and beverages, according to a national survey conducted by the Calorie Control Council, a sugar-substitute industry group based in Atlanta. Roughly two of three people report consuming sugar substitutes several times a week or more in everything from chewing gum and powdered drinks to "lite" yogurts, puddings and ice cream.

Consumption may soon rise even higher. Both Coca-Cola and Pepsi have announced development of new soft drinks, sweetened with a blend of sugar substitutes and corn syrup sweetener to reduce calories and carbohydrates while preserving taste. Coke's C2 and Pepsi Edge are scheduled to start hitting grocery shelves and vending machines this week.

So are sugar substitutes a good thing?

"The calorie savings can be pretty big for people who are high-end sugar users," said Valerie Duffy, associate professor of allied health at the University of Connecticut in Storrs and co-author of a position paper on artificial sweeteners for the American Dietetics Association. Peer-reviewed and published in February, it concludes that "consumers can safely enjoy a range of nutritive and nonnutritive sweeteners" as part of healthy diet.

A teaspoon of sugar has about 16 calories, compared with one calorie or less for an equivalently sweet amount of most sugar substitutes.

But the taste often falls short because sugar substitutes fail "to mimic the sensory properties of table sugar," notes Duffy, who has no industry ties. Many substitutes also degrade at high temperatures, making them unacceptable for use in cooked foods or baked goods. For that reason, food and beverage companies are constantly experimenting to find the perfect recipe of blended artificial sweeteners.

Not everyone thinks that sugar substitutes are always a good thing. "Look at them individually," said Michael Jacobson, director of the Center for Science in the Public Interest (CSPI), a Washington-based consumer group. "Ask how well they are tested and what kind of problems might occur." (More on that below.)

For consumers, the big question, according to Duffy, is, "What do you really like to eat?" Sugar substitutes can trim calories from sugary food and drink. But just because food or drink is sweetened with a substitute doesn't necessarily mean it is low in calories. A lot of artificially sweetened ice cream, for example, has nearly as many calories as the sugar-sweetened stuff because it's loaded with fat. Nor does it make much sense, Duffy noted, "to have a Diet Coke with your second piece of cake."

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