My mom is going for 40 days. She's on day 36 now. She started out weighing 106 pounds (she's 5'1") & got down to 98, then stablized at 100. She feels wonderful & doesn't really want to quit at 40 days. She proves to me that you can't lose too much weight on the MC.
The book says 10 days minimum, I'd keep going.
I'm on day 6 also and hope I can make it to 10... It's been rough for me.