I realize this is an old message but I must add to the comments, as I disagree strongly.
If you fast while breastfeeding you WILL pass those toxins onto your child and you WILL start to lose your BM. I have been there and this is exactly what happened to me and my daughter. Her skin broke out and her breath started to smell awful. An experiment I'll never put my child through again.
WAIT until your child weans.