for all the people who are asking how its possible to live on $20 in food...
I usually only spend about $15-20 a week in food when at home (being a bachelor, i spend about that much in beer too ), but some examples of given foods I eat in a week:

bananas
cereal
granola
sandwhiches (tuna, pbj)
canned soups
salads
frozen .99c pizzas
rice
noodles
tortillas
oatmeal
homemade refried beans for burritos
homemade hamburgers

Eating simply like that, you should have no problem keeping the food bill for one person at only $20. It made not be the most healthy way of eating, but its decent. I generally shoot for about 3000-3500 calories a day. A great way to eat cheaply is to buy in bulk. Im lucky enough to have a winco nearby so I just scoop the bulk stuff out of bins and it goes by weight.

Like I said though, if I'm touring I like to eat out once a day, so just add the cost of fast food or occasional local restraunt, and other than that I eat the same foods as I do at home.

edit: I go to the grocery store every sunday, and I just drug out a few receipts to see what I actually have been spending per week, and the last 3 weeks go $17, $22, and $19. I average right about $20 a week