Short-term use, providing there is no chemical or biological contamination, should not cause harm to anyone, but I would avoid long-term use.
Happy holidays, everyone. I've been on a trip for a while.
I think Pete pretty well sums it up. Pet food is food. It'll nourish you, but it isn't made with human dietary needs in mind, so it's not the ideal food source for long term use if other options were available. But if I were stranded somewhere and had to pick between eating a couple cans of dog food or facing the possiblity of eating human food that could be spoiled or needing to try and find "natural" edible things to eat from the forest, I would prefer the dog food.
I remember back in kindergarden or first grade, me and my friends had one short spell when we'd pass around a box of dog treats to eat on that long school bus ride. It started as a dare, if I recall, but then we all sort of liked them. Seemed a bit hard on the teeth, though. Anyway, just a passing fad.