Is dust edible?
Dust and soil are edible for a while, but then as you eat more, they get toxic. You've been warned.
As culinary items, dust and soil have their advantages. These are (a) their sheer abundance, (b) their fat-free status, (c) presence of abundant trace elements in their natural state, and (d) the lack of competition you will experience in exploiting this food resource. In addition, radioactive dust warms you from the inside, and wet dirt tastes no worse than tofu.
Overall, dust and soil are no real substitute for the food pyramid, or even the Atkins diet.