Hey,

Fatty acids are no longer saturated nor unsatured when stored in adipocytes (fat cells), because they are broken down upon digestion and are broken down into triglycerides, which are then stored in the adipocytes.

Drinking an extra bottle of water a day will most certainly make a difference long term, not only for your metabolism, but also for your entire sense of well-being. Staying hydrated is the most important thing you can do for your health. It will aid in better skin, better hair, less water retention, lower blood pressure, increase in energy, better sleep, better concentration, etc. It's just so important. One should get at least 2-3 liters of water every day, so I hope you were not saying that this one bottle of water was the only one you consume throughout the day.