muscles and fasting

Hi Kelly,
I started reading the books to take the exam to get certified through AANC as you did. But Im coming up with questions already in what Im reading.
Ok, for starters, Im thin, 95 pounds at 5'3. I eat 2500 calories a day and run 12 miles a week or so. However, I fast for spiritual reasons so Im interested in NOT losing muscle since I have so little to spare. My choices are to juice and green foods fast strictly with added oil (I dont do well without the flax oil). OR, modify the fast and eat my 2 whey shakes each day and a couple peices of fruit. My question really is, which will be better for me for the next 21 days physically?
AND, will I be losing muscle? fat? or bad cells?
Thanks
katie Tweet