You sound like me. I have been juice fasting for 57 days, and I must admit...I'm dissapointed.
I may have lost 10 pounds total, but I guarantee at least 6 are from pure waste. My stomach did go down...it's actually flat, but has almost no definition. Apparently I'm genetically programmed to carry as much body fat as possible - even in my breasts! I only went down 1/3 a cup size! Now during this while time, I only hit the gym once, and I hate to say it, but it was a waste. Usually after weight training I feel great, and even see results the next day...not thsi time. I think what you've heard is true...light cardio.
I'm still figuring things out myself. At this point, I'm still not hungry, but my body isn't doing so well...wish I had guidance from the beginning. I think I'm going to eat soon...I miss feeling toned, and at least most of the crap is out of my colon. Good luck.