London, February 11 : Conventional wisdom that low-calorie artificial sweetener can prevent weight gain seems to have been scotched by a Purdue University study, in which rats fed on such sweeteners were still found to put on weight.
Writing about their findings in the journal Behavioral Neuroscience, the researchers expressed their belief that a sweet taste followed by no calories might make a the body long for extra food.
During the study, the researchers gave different yoghurt to different groups of rats, some sweetened with sugar, and some with saccharin. The animals were later given a plentiful supply of food.
It was observed that the saccharin-fed mice ate more calories, put on more fat, and gained more weight than their sugar-fed counterparts.
Such animals did not make any attempt to cut back on their food later to regulate their weight, say the researchers.
"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 higher calorie sugar," the BBC quoted the researchers as writing in the journal.
According to them, one theory could be that in normal conditions, the arrival of a sweet taste in the mouth helped prime the metabolism for the arrival of a calorie-heavy, sweet meal into the digestive system.
When the meal did not arrive, they said, the body might get confused and have more trouble regulating its appetite when other food was around.
If that were the case, said the researchers, other low-calorie sweeteners like aspartame, sucralose and acesulfame could have a similar effect.
The British Nutrition Foundation said that the Purdue team's findings were of "interesting".
However, issuing a statement through a spokesman, the institution said that the study did not prove that artificial sweeteners could be counterproductive in dieting humans.
"This needs far more research - as studies in humans have shown that low-calorie sweeteners can help people lose weight," the spokesman said.