Wont charlie realize that Bella is a vampire when she stops eating human food?

No, because if you read the books, Alice and Edward repeatedly excuse themselves from breakfast,lunch, or dinner over Charlie's house. Bella could just say she already ate or something.

oh okay, i havnt read the books :L my friend lent me them and i should do soon, i hardly ever read so its gonna be a challenge for me to read a whole 500 page book and the others!