Your grandparents lived in a simpler time when food was healthy, homemade, and cheap, right? Wrong—at least that last part. Although food prices have obviously risen in the past half a century, our spending on food as a proportion of income has actually decreased drastically since the 1960s.
A new chart published by the U.S. Department of Agriculture shows how the average share of per capita income spent on food fell from 17.5 percent in 1960 to 9.6 percent in 2007, rebounding a little to land at 9.9 percent in 2013. Annette Clauson, an agricultural economist with the USDA's Economic Research Service who helped calculate the data in the chart, explains to NPR's The Salt, "We are purchasing more food for less money, and we are purchasing our food for less of our income. This is a good thing, because we have income to purchase other things."
As the graph shows, this is mostly due to falling (relative) grocery prices. The percent of income dedicated to eating out has actually risen, slightly, over the years, while the per capita cost of food consumed in the home has plummeted.
Of course, things are not totally equal across socioeconomic divides; the less money you make, the greater portion of it you'll be forced to spend on necessities like food, even if wealthier families are still spending a higher total amount. For example, in 2013, the lowest income bracket spent on average $3655 annually on food, or 36 percent of total income. Meanwhile, people in the highest income bracket spent about $11,000 annually on food—more than double the total amount, but still only about 8 percent of their earnings.
You can check out all the data, including how different countries compare, here.