A few months ago, in a session to generate ideas for our upcoming Food issue of Technology Review, I asked a question that was troubling me: Why do people still starve?

Starvation, hunger and food insecurity seem to me the most troubling symptom of our inability to actually make societal progress. For 100 years or more we have seen widespread revolutions in almost every part of the food system, and we’re generations into trying to prevent hunger—yet even when levels reduce (and they are not always reducing) it’s desperately far from eliminated.

The World Food Program won a Nobel Peace Prize this year: meanwhile hundreds of millions of people are hungry or starving, and there are kids in even the most developed countries who don’t get enough to eat. (This recent New York Times Magazine photo series by Brenda Ann Keneally was physically painful to read.)

As often happens when you pose a question in an editorial meeting but don’t necessarily have a good answer on the spot, I ended up trying to tackle it myself. Fortunately, there are many very smart people out there and, in the last year or two, there have been a few really, really good books that tackle some of the questions about the past, present, and future of the food system.

The result was this essay on why people starve.

The answer, really, is because the system lets them. It needs some people to be on top of the pyramid, and others lower down.

Just as healthy calories are hard to come by for those who are poor, the industrialization of farming is unevenly distributed. First Western farmers were catapulted into hyper-productivity, then the nations touched by the Green Revolution. But progress stopped there.

Today, a hectare of farmland in sub-Saharan Africa produces just 1.2 metric tons of grain each year; in the US and Europe the equivalent land yields up to eight metric tons. This is not because farmers in poorer regions lack the natural resources, necessarily (West Africa has long been a producer of cotton), but because they are locked into a cycle of subsistence. They haven’t industrialized, so they don’t grow much food, which means they can’t make much money, so they can’t invest in equipment, which means they can’t grow much food. The cycle continues.