yes you should work out durning a fast it helps kep you motivated makes you feel good and helps rid your body of access water plus help you burn away more fat cells....but because your not eating when you work out your body eats away fat stores but it also takes muscle because of extra stored protien and combo fats that r kept in lean muscle mass. but for most of us women i know myslef i always like to loose a little muscle mass i hate looking bulky, but it still will be taking most of it's much neded energy from stored fat cells.