I did a 60 day cleanse a few years back, and in the mid-forties experienced True Hunger for the first time, a peculiar dull ache in the solar plexus that no amount of lemonade would fill.
My excellent Naturopath had me switch to juices and BAM! I became jette propelle to the big finish! If you cannot continue on lemonade and still want to cleanse deeper, don't hesitate to switch to juices.
My break from that mega fast was tricky, and actually took about six months. I lost hair; I was fortunate to have the support of my naturopath who explained the changes and help me through them, including a small kidney calcification I passed in the middle of the fast. I would surely have stopped without her--it was scary.
Over 40 is a real oddyssey--but it can be done. In my case, it was the turning point in my health--for the better!