Chocolate not only tastes good, but it also apparently activates the part of the brain that blunts pain and makes it difficult to stop eating, according to a study published Wednesday in the Journal of Neuroscience.

But a much leaner choice has the same effect -- drinking water, say University of Chicago neurology professor Peggy Mason and neurobiology research associate Hayley Foo.

Mason and Foo gave rats either a chocolate chip to eat or water to drink as they lit a lightbulb underneath their cages, Agence France-Presse reports.

The heat usually caused the rats to lift their paws.

But when they ate chocolate or drank water, their pain response to the heat was dulled and they did not lift their paws as quickly.

Mason said that eating stimulates a system in the part of the brain that controls subconscious responses known to blunt pain.

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