London: Next time you're craving a bar of chocolate, give in.

Your waistline might not thank you for it — but your brain will.

Research has revealed that obsessing over a sweet treat is such a drain on the brain it makes it difficult to concentrate on other tasks.

Fighting an all-consuming desire for chocolate ice cream can have consequences ranging from memory lapses to car crashes, say scientists.

The research centred on cravings for specific foods and brands.

Someone experiencing a craving wanted to eat a particular brand of biscuits or flavour of ice cream.

An Australian research team set out to see if the intensity of these desires affected our ability to concentrate on other things.

They found that volunteers whose favourite chocolate bar was unwrapped and within their reach while they sat a series of tests had slower reactions and poorer memories than those who did the same tests in a chocolate-free zone.

Writing in the journal Current Directions in Psychological Science, the researchers, from Melbourne's Flinders University, said: "Although cognitive effects of individual food cravings are likely to be small, in practice even small reductions in cognitive resources have the potential to compromise optimal performance in everyday situations, thereby reducing work efficiency or increasing the likelihood of accidents.'