Drink it up! The Journal of Strength and Conditioning Research did a study in 2008 showing that just being dehydrated 3% reduces strength and power by 19% (1)!!

Not only does becoming dehydrated reduce strength and power, but the stress it puts on your body can actually raise cortisol levels causing you to store fat more easily!!

Simple logic would say that if being dehydrated can cause you to store fat easier (or at least make it more difficult to burn off), then staying properly hydrated will make you more efficient at burning off body fat.

So keep hydrated during those workouts!

Source:

(1) Jones, L.; Cleary, M.; Lopez, R.; Zuri, R.; Lopez, R. (2008)Active Dehydration Impairs Upper and Lower Body Anaerobic Muscular Power.JSCR. March. Pg 455-463.