A newly developed weight-loss aid is scheduled to be released in Britain next year. The aid comes in the form of crystals, which, when scattered over food, tricks the body into thinking it is full. Unlike other weight-loss methods, the crystals could provide lasting health benefits, according to experts.

Six-month-long trials, with more than 1,400 dieters, showed the crystals' effectiveness. The participants lost an average of 2 stones. This trial will be followed by a five-year trials, which will follow 1,000 dieters.

The crystals were developed by Dr. Alan Hirsch, a neurologist at the Smell and Taste Treatment and Research Foundation in Chicago. He explained that the smell of food accounts for up to 90% of its `taste'. This smell has been co-opted y the crystals to trigger a `fullness' message in the brain, in order to prevent further eating.

The crystals are called Sensa Tastant granules, and are free of sugar, sodium, gluten, stimulants and calories. They have already become available in health food shops in the US. They are set to be released in Germany, Canada in Mexico.

Dominic Dwyer, a neuropsychologist from Cardiff University, agrees that the idea is principally logical. "If you increase the intensity of a food taste or smell it makes more of an impact on feelings of satiety. He does warn that the product will have to be used with care. "A mouth-watering smell from food can simply make us eat more."