Rat study ties artificial sweetener to weight gain

By Will Dunham

WASHINGTON (Reuters) - Using an artificial, no-calorie sweetener rather than sugar may make it tougher, not easier, to lose weight, U.S. researchers said on Sunday.

Scientists at Purdue University in West Lafayette, Indiana, studied rats that were fed food with the artificial sweetener saccharin and rats fed food with glucose, a natural sugar.

In comparison to rats given yogurt sweetened with glucose, those that ate yogurt sweetened with saccharin went on to consume more calories and put on more weight and body fat.

The researchers said sweet foods may prompt the body to get ready to take in a lot of calories, but when sweetness in the form of artificial sweeteners is not followed by a large amount of calories, the body gets confused, which may lead to eating more or expending less energy than normal.

"The data clearly indicate that consuming a food sweetened with no-calorie saccharin can lead to greater body-weight gain and adiposity than would consuming the same food sweetened with high-calorie sugar," Purdue researchers Susan Swithers and Terry Davidson wrote in the journal Behavioral Neuroscience, published by the American Psychological Association.

"Such an outcome may seem counterintuitive, if not an anathema, to human clinical researchers and health care practitioners who have long recommended the use of low- and no-calorie sweeteners as a means of weight control."

Other artificial sweeteners such as aspartame that also taste sweet but do not lead to the delivery of calories may have similar effects, the researchers said.

"Animals may use sweet taste to predict the caloric contents of food. Eating sweet noncaloric substances may degrade this predictive relationship," the researchers wrote.