A、By imagining competing images. B、By substituting it with healthy food. C、By reducing the amount of in-take. D、By forming a men

(23)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 that it makes it difficult to concentrate on other tasks. The researchers, from Melbourne’s Flinders University, center on cravings for specific foods and brands. They found that someone experiencing a craving isn’t just hungry, they want to eat a particular brand of biscuits or flavor of ice cream, and nothing else will do. The research team set out to see whether the intensity of these desires affects our ability to concentrate on other things.(24)They found that volunteers whose favorite 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. The researchers believe that when we crave a food we draw a mental picture of it. This picture ties up brain regions needed for other tasks, including math and memorizing and the consequences don’t end there. Writing in the journal Current Directions in Psychological Science, the researchers 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."(25)But the researchers also believe that filling the brain with competing images, such as visualizing a rainbow, can ease cravings. Researcher Dr. Eva Kemps said, "Engaging in a simple visual task seems to hold real promise as a method for curbing food cravings."
23. What is the passage mainly talking about?
24. What has the research found according to the passage?
25. According to the researchers, in what way can we ease our desire for food?