The United States has a sophisticated, diversified and highly productive agriculture. It also has an abundant, varied diet that costs only about 10% of the average consumer’s disposable income. These facts are familiar and frequently repeated, but do they add up to a food system?

They do not. They are at best attributes of a food system, but they do not describe that system. Policy officials and private actors seeking to shape the food system would gain from a more comprehensive view.

That fuller description begins by teasing apart the four different dimensions of the production side of U.S. agriculture. One of them clearly is to produce food, feed, fiber and fuel for American consumers as well as for many foreign consumers whose local farmers cannot provide adequate supplies reliably and affordably. Between 1995 and 2012, the value of U.S. agricultural output doubled, a testament to its productive capacity.

A second role is to provide incomes to workers, farmers and landowners. U.S. agriculture generally has done well on this score since 2000. Farm incomes are at record levels; land prices have been appreciating at double-digit rates, and agriculture supports about 10 million jobs.

A third role is to release land, labor and capital to seek returns in other, faster-growing segments of the economy. This is a necessary result of Engel’s Law: that people spend a declining share of their increasing incomes on food. From a peak of 7 million farms in 1935, the farm population has declined below 2 million farms (and three-fourths of them earn incomes off the farm). Cropped acreage has declined from a high of 380 million acres to 330 million. Today, agriculture as a whole involves only one-tenth of the U.S. workforce, reflecting not only agriculture’s rising factor productivity but also the growth and diversification of the non-farm economy.

The final role of agriculture is as a demand engine for non-farm products and services. Modern agriculture uses many inputs — equipment; chemicals; finance; seeds and breeding stock; etc. — and relies on many output-handling services — processing plants; transportation companies; packagers and retailers; and energy, finance, legal, accounting and advertising services. All told, 90% of food expenditures actually go to these ancillary providers.

A food system

But all of this does not add up to a food system — which encompasses not only agriculture’s role but also the values, preferences and demands of the society within which farming resides. And a food system also must take into account how these various social pressures are brought to bear on the food supply chain. So, what are those pressures that affect the food system, and how do they re-shape it?

One core element that must never be taken for granted is food security. Globally, there are 800 million to 900 million chronically hungry people and tens to hundreds of millions more who are malnourished. No food system can turn its back on this fundamental need.

The U.S. food system is being asked to do much more. Food safety is a large and increasingly complex challenge as supply chains get longer and cross more borders. There are not enough food inspectors to ensure that the food we eat is safe. We increasingly depend on the food system — from the farm gate to the consumer’s table, through sound science and best practices — to deliver safe food.

Greater health and wellness represent another challenge. Vitamin deficiencies largely are gone from the American scene. They have been replaced by new concerns — obesity and other diet-related diseases; additives; supplements, and the like — that reflect new societal interests.

Biotechnology presents another facet of the food system. Scientists are able with increasing power and precision to engineer biological processes. Some are embedded in seeds or animal traits, some in fermentation or processing agents, some in plants to produce new pharmaceuticals or industrial compounds, and some to replace or extend fossil fuels. Biotechnology, nanotechnology and digital capabilities will create new frontiers of hazards for the food supply and new ways to manage them.

Finally, a widening array of values and preferences are being superimposed on the production of food. Food animals are to be treated more humanely while receiving fewer antibiotics. Carbohydrates, fats and proteins are to be produced more sustainably — usually meaning with less land, water and pollution. Reducing wastes — both from the production line and from usage — has received renewed emphasis. Slowing and adapting to climate variations and change are pressing concerns.

New ideas, new opportunities

These diverse and multiplying social pressures may have very different effects, depending upon how they filter through to food production and distribution. New ideas and information create new opportunities. Wider and more competitive markets bring added choices and efficiencies. Taxes and subsidies tilt outcomes in favored directions. Bans and mandates anoint winners and losers.

All of this — the traditional roles of agriculture, the new social pressures and the ways in which these interests are brought to bear — create a more complex and dynamic structure: an inter-connected food system. Both policymakers and private actors need to think more holistically about an integrated food system rather than crafting policies or strategies for its disjointed component parts.