Q: I bite my nails. Trying to stop but cannot stop. Would my fast be broken is I bit my nails? (email)

A: Biting nails is a bad habit. Biting nails causes unwanted germs to go into the mouth and stomach. Thus, due to the germ factor, not only are you reducing the quality of your health, you are also eating filth. Biting nails is makrooh. Doing so would not invalidate the fast.

Allah Certainly Knows Best.