2008-02-11 06:41:37
A study which showed that rats fed on artificial sweetener still put on weight
has baffled researchers.
Scientists from Purdue University in the US now believe that a sweet taste
followed by no calories may make the body crave extra food.
Their research, published in the journal Behavioral Neuroscience, found that
rats fed sugar subsequently had lower appetites.
But nutritionists say that low-calorie sweeteners are still best for health.
The data clearly indicate that consuming a food sweetened with no-calorie
saccharin can lead to greater body-weight gain
Purdue University researchers
Conventional wisdom says that, as part of a calorie controlled diet, artificial
sweeteners can help people lose weight or keep it off.
But the Purdue study turns that wisdom on its head.
They gave different yoghurt to different groups of rats, some sweetened with
sugar, and some with saccharin.
They were then given a plentiful supply of food, and the researchers observed
the results.
The saccharin-fed mice ate more calories, put on more fat, and gained more
weight than their sugar-fed counterparts.
They did not make any attempt to cut back on their food later to regulate their
weight.
Sweet expectations
The researchers wrote in the journal: "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."
One theory, they said, was 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 does not arrive, they said, the body may get confused and have
more trouble regulating its appetite when other food is around.
They said that if this were the case, other low-calorie sweeteners such as
aspartame, sucralose and acesulfame could have a similar effect.
A spokesman for the British Nutrition Foundation said the study findings were
"interesting", but 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."