Whether caffeine is bad for you may have more to do with how much you consume than the substance itself. According to Dr. Karen Rosewater, caffeine is a stimulant that affects the body similar to the way an upper does, when consumed in excess. Taken in large amounts, she says, caffeine can markedly elevate heart rate and blood pressure. In addition, it may cause jitteriness or make it difficult for you to sleep.

Since you haven't reported any of these problems, you are probably consuming caffeinated substances at a moderate level. But, if you do start to feel as though you're a bit too jumpy or you can't fall asleep at night, you might want to cut back a little. Try decaffeinated beverages, or just consume a fewer number.

Oh, and don't forget to check the labels on the soft drinks you consume. You'd be surprised how many non-cola sodas contain caffeine--some orange sodas, for example!