the G-man wrote:
I'm going with part of the virus's changes is to make the zombie body more resistant to decomposition.
Yet we see decomposition, going all the way back to the first episode and "bicycle girl
She was eaten by a large group of zombies.
If zombies ate a person and literally all that was left was the brain which the zombies couldn't get to through the skull, that brain would be an active walker brain with no body to control.
And to address a few misconceptions relating to zombies I'd suggest checking out the early Romero moves this series is based on, to clear up a few points;
* Anyone who dies through any means will reanimate as a zombie unless there has been brain trauma.
* Being bitten by a zombie doesn't give you the 'zombie virus', but it will lead to death due to infection which cannot be treated (aside from immediate amputation), it is this death which leads to the inevitable reanimation.
* Zombies behavior is controlled by instinct and they have a drive to eat, but the food they swallow is not in any way processed by their body, which is dead and doesn't have working digestion etc. You can remove a zombies stomach and it will still eat, with the chewed up food falling out onto the floor, this would not lead to a quicker decomposition.
* It is unknown whether zombies continue to decompose or at what rate, they do become damaged over time though as their bodies cannot heal as they are dead.
* Most importantly, nobody knows why everyone reanimates and they never will. The zombie plague isn't an important part of the story, it is a plot device to justify an apocalypse in a horror setting. The story is always focused on the characters and how they react to the situation.