It varies considerably over the course of the day due to water retention, it's not a fast and hard number during the course of a single day, you could be + or minus a few lbs based on the amount of your fluid intake and the amount of salt you have consumed. Weigh yourself in the mornings before you have coffe and bfast and after you use the restroom, and then compare those morning numbers to each other and see if the 2 lbs is the result, for example, each Monday morning's weight should be 2lb less then the previous Monday, on an empty stomach with an empty bladder and colon.