Hybrid
Before the mutation of plants and trees had occurred, survivors had the problem of acquiring food supplies. Often-times, they would explore the buildings and search for goods that could still be eaten. If worse comes to worst, they would even scavenge the spoiled goods just to go by the day.
Only those who have evolved and became stronger could avoid eating without getting weak for a few days.
Before the mutation of plants and trees, food shortages were an everyday occurrence.
That is why some of the human survivors resorted to the most disgusting thing a human being could do, during an apocalypse.
Eating Human Flesh. a.k.a Cannibalism
Such humans who eat human flesh can no longer be considered as humans. They are even worse than the mindless zombies who only followed the orders of the Apocalypse Virus inside them.