Blood? That’s so old school. They eat zombie pears.
Old School Zombies are closely related to humans, but those have been in the literature for a long time. Your zombie novel will be released into the future, and will need to fit into future social trends and fears if it is to sell. Book zombies won’t cut it. Zombie food is one future stress point. Zombie water will be another.
Zombies are not fiction. They are environmental markers written on human body images, like tattoos. Yes, dear Author, you are a tattoo artist! Good to know!