You don't have to weigh daily. You should be your lowest weight on day 3 or 4. It is written this way to accelerate weight-loss in the beginning of the week. When the metabolism starts to properly work you will FEEL the difference. You will also be urinating more because you will be expelling the excess fluids in your tissues.
Water is necessary for proper metabolic function.
No sodium seltzer,flavored OK, is acceptable, but tap water is still the best. You didn't gain it overnight. It took many days upon months, and years to get you here. Now the process needs to be reversed, one day at a time. When you hit your weight-loss goal Body Transformers will teach you how to keep it off with our maintenance program.