People who drink too much--or too little--caffeine may be putting themselves at risk for headaches. The Norwegian study found that those who drank many caffeinated drinks every day had 18 percent more non-migraine headaches than those who drank only a few. For the study "many" drinks amounted to more than five cups of coffee, while "few" involved only one or two cups. But interestingly, the researchers also found that those who had low caffeine consumption were more likely to experience chronic...