ASSUME by your weight your female, you didn't mention your height as well or how much you have lost since day one.
You pick a weight that you don't drop past and when you reach that weight, you eat as much fresh fruit as needed to maintain your weight/...THAT SIMPLE.
That way 40 days seems like nothing.
To do zero food other than strained juice for 21 days, BREAKS HABITS or better said; ADDICTIONS.
30+ days gets you new skin if all the organs are working well enough by then.
NEW BLOOD @ 14 days
NEW HEART @ 21 days
NEW SKIN @ 35 days
NEW LIVER by the time your done your 40.
Good Luck 50+ person which also points at being female and once your attracking attention as people ask you how you stay so young, then you may be proud of your weight and age.