First it is important to realize that caffeine just isn’t that easy to digest. To break down the coffee you ingest and deliver that burst of energy to your blood stream, your liver uses enzymes. If all of your enzymes are hard at work within your liver trying to break down the caffeine, they aren’t ready and active in your blood to knock out other bad chemicals it needs to get rid of. People who drink too much coffee often have difficulty getting rid of chemicals from their bodies, and their liver function is off.