Question for my sister

My sis is on day 5 of her fast and her rings have gotten so tight that she can't get them off except with soap....what is this? Her tummy doesn't feel over bloated or anything but it seems like she is hugely retaining water. She is drinking a lot of distilled water so it shouldn't be dehydration she is peeing all the time...if you have experience this or know why this is happening please let us know...thanks Tweet