Why Are There No Fat Zombies?

Zombies have serious nourishment problems. All the human flesh they gulp seems to do them no good. Maybe, when first bitten, there’s meat on their bones. However, in a few hours, days or weeks, they tend to look like the guy on the right. Ever see a zombie, especially one who has just eaten someone, take a satisfied nap? I think not.
They have terrible digestive problems as well. Ever see a