“I learned from my two years’ experience that it would cost incredibly little trouble to obtain one’s necessary food, even in this latitude; that a man may use as simple a diet as the animals, and yet retain health and strength. I have made a satisfactory dinner . . . simply off a dish of purslane … which I gathered in my cornfield, boiled and salted. . . . Yet men have come to such a pass that they frequently starve, not for want of necessaries but for want of luxuries.”
~Henry David Thoreau, Walden Pond
Before you run out into your back yard and start munching, I suggest that unless you're extremely sure of what you have, you consult an expert or even take a class on wild foraging. Not only are many weeds good for you, they're both work-free and cost-free. A triple bonus!