Last updated at 09:40 11 February 2008

One of the first rules of weight watching has always been: Put the sugar bowl at the back of the cupboard and use low-calorie sweeteners from now on.

But researchers suggested yesterday that dieters might be better sticking with sugar after all.

They think that a sweet taste can prompt the body to prepare for a large intake of calories.

When this does not arrive, the body then becomes confused and either demands more food or burns less energy - with the result showing on the scales.

"The data clearly indicate that consuming a food sweetened with no-calorie saccharin can lead to greater body-weight gain than the same food sweetened with high- calorie sugar," say the U.S. team behind the research.

They accept that the finding will seem baffling to those who have long recommended the use of sweeteners to

control weight.

Other artificial sweeteners such as aspartame which do not lead to the delivery of calories could have similar effects, the researchers said in the journal Behavioural Neuroscience, published by the American Psychological Association.

Scientists at Purdue University in West Lafayette, Indiana, fed some rats with yogurt sweetened with saccharin and others with yogurt sweetened with glucose, a natural sugar.

The saccharin-fed rats went on to consume more calories and put on more weight and body fat.

The research drew a critical reaction-from the food industry.

"This study oversimplifies the causes of obesity," said Beth Hubrich, a dietitian with the Calorie Control Council, representing companies which make diet foods and drinks.

"The causes of obesity are multi-factorial. Although surveys have shown that there has been an increase in the use of 'sugar-free' foods over the years, portion sizes of foods have also increased, physical activity has decreased and overall calorie intake has increased."

The council also said findings in animal studies might not be applicable to people, which the researchers acknowledged.

Davidson responded that the implication of the council's statement "that they, too, are interested in the health of the public seems insincere. If they were sincere, one might expect that they would be alarmed by findings from animal or human models suggesting that their products might be contributing to the obesity epidemic that continues to expand and do its damage."

Britons eat an average 150lb of pure sugar a year - more than 12lb per month.

The typical family gets through 52lb a month of sugar in its different forms.

The toll on health can be devastating. As well as causing dental decay, too much sugar can lead to obesity and type 2 diabetes, raising the risk of heart attack and stroke.