From the standpoint of fat loss, you want to be in a position metabolically where the liver is converting stored fat to energy. The liver has other functions, but this is one of its main jobs.
Unfortunately, another of the liver’s responsibilities is to pick up the slack for the kidneys, which need a lot of water to work properly. Actually, your kidneys need a lot more water than most people realize.
If the kidneys are water-deprived, the liver has a double duty assignment. It has to do the work of the kidneys along with its own work. This double time assignment only serves to lower the actual productivity of the liver. It then can’t metabolize fat as quickly as it could when the kidneys do their job with efficiency.
If you allow this to happen, not only are you being unfair to your liver, but you’re also setting yourself up to store fat because you've made the liver less efficient at turning stored body fat into energy.