1 Week Complete on Atkins 20, Down about 9lbs!

On the atkins 20 you will lose a lot of water your first week or so. It can make an immediate impact on how you feel because weight is weight even if a fair amount of it is water. Water won't stay gone though and you will see likely see up and down fluctuations for most of your journey. You will also likely see times where water weight is masking fat loss for a period of time.

I suggest reading this:

http://physiqonomics.com/the-weird-and-highly-annoying-world-of-scale-weight-and-fluctuations/