Take a second to count the number of cups of coffee or black tea you drink a day. Now consider this: these caffeine-containing beverages have zero nutritional value. Caffeine is immensely addictive and found in chocolate, sodas and many over-the-coucounter medications. Caffeine can elevate the mood, energize, delay fatigue, and stimulate the central nervous system. It can also cause hands to tremor and the heart to palpitate. So, why is caffeine our national drug of choice? Caffeine feeds our cultural...