2 lbs in 4 days seems like weight loss to me.
I tend to think the body, left alone without over exercise, will find it's own balance during fasting.
Just to be certain, you are doing very much activity in the first 3-4 days of a water fast?
I'm at the evening of day 3 and I just could not imagine running! I hand did my laundry and was happy I could pull that off.
Having said that, I think I'll have more energy on day 4 and on but I'll try to stay in a resting position to let my body heal and do it's work