One of the livers main functions is to metabolize stored fat, and if it has to help the kidneys, it can't metabolize the fat at normal levels. So less fat is metabolized, and more remains stored in your body. That means no weight loss. Keep in mind that water also rids the body of metabolic waste , and as you lose weight you have much more metabolic waste than normal. The heavier you are, the more water you need to make sure these processes function smoothly.
Water maintains muscle tone.
It is a primary part of the process of contraction. Water also prevents sagging skin after weight loss by keeping it firm. Water prevents constipation. The CO2 gets breathed out immediately, while the water takes a while to leave the system. Eventually your body will be used to the amount of water you drink, and the bathroom trips will lessen over time.