PepsiCo Inc. announced Friday it plans to change the recipe for Diet Pepsi. The soda will now be sweetened with a mix of acesulfame potassium and sucralose, instead of aspartame. "Diet cola drinkers in the U.S. told us they wanted aspartame-free Diet Pepsi, and we're delivering," Seth Kaufman, senior vice president of the Pepsi and flavors portfolio subsidiary of the company's North America beverages unit, said in a statement cited by CNBC. "We recognize that consumer demand is evolving, and we're confident that cola lovers will enjoy the crisp, refreshing taste of this new product."

Although aspartame has repeatedly been declared safe by the U.S. Food and Drug Administration, it has been linked by online users to cancer, memory loss and obesity. True or false, the rumors has caused the sweetener to become unpopular among consumers, as the Wall Street Journal reported. Diet Pepsi sales fell 5 percent last year, and Kaufman said removing aspartame was its drinkers' "No. 1 concern."

Diet Pepsi's new sweetener is sucralose-based. Frequently marketed as Splenda, Sucralose is 600 times sweeter than regular sugar, according to the Beverage Institute. About 80 countries have approved it for use in food and drink, and the FDA OK'd it in 1998. It has no known side effects and no calories. It also doesn't affect blood glucose or insulin levels.

Acesulfame potassium, the other sweetener in the new Diet Pepsi recipe, is 200 times sweeter than sugar. Nicknamed ace-K, it's been used in American food and drink since 1988, according to the International Food Information Council Foundation.

Among PepsiCo's portfolio of diet drinks, some are switching sweeteners and others are not. Affected will be Diet Pepsi, Caffeine Free Diet Pepsi and Wild Cherry Diet Pepsi; unaffected will be Diet Mountain Dew, Diet Sierra Mist and Pepsi Max. Consumers can buy the reformulated sodas beginning in August.

The Coca-Cola Co. responded to the PepsiCo move Friday with a statement saying it did not plan to change the recipe for Diet Coke, which contains aspartame. "All of the beverages we offer and ingredients we use are safe," the company told USA Today via email. Diet Coke sales by volume fell about 7 percent last year.

Neither PepsiCo nor Coca-Cola disclose the amounts of aspartame in their drinks, but 12-ounce cans of soda typically have about 192 milligrams' worth, according to the American Cancer Society. A 165-pound person could consume more than 19 such cans in a day before going over the highest acceptable level set by the FDA, the society said.