If you're concerned about losing weight, I would add more maple syrup to your drinks if you find yourself losing (thus less for those who need to lose weight). In reading the book, SB said if your weight is stabilized, you should not lose that much. For folks like me (overweight) I would anticipate losing much more -- since naturally my body has more to give up/burn.
From what I understand you can start the first day with a SWF.