Hi Motherweary! According to http://www.nhlbisupport.com/bmi/
your body mass index is 20, which is quite low. If you lose too much weight I think your body will get hungry, bella lucia reached completion after 20 odd days.
Your husband sounds healthy enough if he is climbing trees every day! Not sure why he needs to fast, but maybe try it on a holiday? Wouldn't be good if he got a dizzy spell up a tree with a chain saw :-)