28 Days Later is the most plausible of the whole genre. It’s also because they are not true zombies, meaning they are not dead people brought back to life somehow. They are living humans infected with a virus that causes them to fly into a murderous rage, and will die eventually because outside of cannibalism, they can’t really feed or take care of themselves.
In TWD, the zombies DO eventually die if they don’t feed, just slower than we would. I remember someone saying that this last season.