Sara Davis conceives of the still life and the artistic portrayal of zombies as two forms of memento mori – a symbol of death’s inevitability:
For the 17th century Dutch merchant class, a still life was a shrine to the beauty and pleasure that money can buy: luxuries, delicacies, fine things that could be held in the hand or captured in oils, a small and fine possession in itself. But for contemporary society, the ultimate shrine and symbol of prosperity is the well-kept body — that is, a body that falls into a fairly narrow category of healthy, beautiful, and athletic. Despite all the goods and brands and tech toys, so much more of our collective wealth is sunk into sculpting or tightening, brightening or darkening, coloring and trimming, running, counting calories, and swallowing gallons of “smart” water.
An interesting take, no? I've always liked the "Zombies as a symbol of disease" idea, which is in line with the genre being a stylized reaction to our fear of death. What I haven't heard a good explanation for is why the sudden shift from the zombies of old, which slowly lurched around, to the newer zombies who can run and sprint and basically do everything a normal person can do. (Although I like Jeff Bryan's take: "When we're always gulping down caffeine and 5-hour energy tablets, that's going to have an effect on how we behave in our second life as zombies.") Perhaps it has something to do with the scary super viruses that seem to loom over our future...It makes sense, then, that today’s bogeyman and morality tale is a decaying body, a walking (or running) death’s head that all the cardio and training in the world can’t outrace. Zombies mock us, like the half-eaten fruits of the Dutch golden age and the weary speaker of Ecclesiastes, that though we may define ourselves by what and how we consume, it is all a pretty distraction from how we will be consumed.