I was using an extreme example in order to make a point. Chocolate can change your mood, I was trying to avoid the obvious tobacco and alcohol comparisons. This is because many right wingers will happily say that tobacco and alcohol if they were to be introduced now, wouldn't be legal. However they are happy to allow this status quo as it generates billions every year in taxation. Also because they claim it would be hugley unpopular for a government to try to ban them. As for unhealthy food, it costs any health service a huge amount of money every year to treat heart disease, liver disease malnutriton etc, yes it may not cause dysfunctional behaviour to the same degree that drug MISuse, it has been shown that poor diet can impact negatively on children's physical and mental development.