Or, how much of what you spend is spent on food? More or less over the years? Here's an interesting chart on the food expenditures by families and individuals as a share of disposable personal income from USDA. The high is in 1933, when I think farmers were plowing under rather than sell at depressed prices, or couldn't get the crops out of the fields, or couldn't get credit to plant. Shortages mean higher costs.
We are currently spending 9.5% of disposable income (not gross) on food. And eating more it seems! Definitely more calories per dollar. Looks like the more industrial agriculture/food manufacturers centralized and commodified food, the cheaper it got. Ok, great, you say. Hmmm.. how's your health? How is the health of your community? Diabetes rates among the poor? High blood pressure? Can your kid take peanuts to school for a snack? Allergies, eh?
Supporting local food, local community health and local farmers might mean using more of our dollars to purchase food, but we are buying much more than just lunch. Not least might be the ability to purchase food at all, or to be secure about the sources of our food.