I have been wondering this same question for a while now! I've used the P&B shakes in the past with great success (expelled mucoid plaque, clear skin).......actually I think I may have "over-used" it. I was on it for 7 weeks at 2 shakes per day. I am petite (5'4, 108 pounds) That is why I was questioning if maybe it was the aluminium or like you mentioned below the destruction of the vili (because I've heard that too!) but I think that I just depleted myself and didn't build myself up in the process. I was doing other cleanses as well at the time. My "depleted" symptoms consisted of muscle weakness and social anxiety. I am seriously overdue for a clease and was trying to figure out which one I wanted to do. Your post and unyquity's post (thank you!! amazing!) has helped me in that decision. Did you decide on a cleanse yet?