The modern food system has been in place for barely a half-century and the agricultural practices behind it have already assumed the term “conventional”, despite being a synthetic departure from what had been the norm for thousands of years. This monumental shift has had benefits as well as consequences. On the one hand, the average person in a developed country today spends less of their income on food than at any point in human history, less than 10% of their income in the United States.¹ And while the severity of hunger continues to be a serious concern in many developing countries, the threat has been reduced by nearly a third since 2000.² On the other hand, calories from conventional agriculture have led to the problem of rampant obesity, creating an unsustainable burden on our health and our economy. The aim of this post is to review the “nutrition transition”, a global trend in recent history that informs our study of food and its effects on modern society. – Importantly, all three transitions discussed in this post apply to averages, and since population statistics apply to rates of incidence, not individual outcomes, there will always be outlying exceptions.

The “nutrition transition” is a theory developed in 1993 by Barry Popkin to describe the global dietary shift from whole foods to processed foods that began during the mid-late 20th century. Popkin was supplementing two older theories that also describe changes in the human population over time: the “demographic transition” and the “epidemiological transition”. Each of these offer valuable explanations for how society has changed, but the biggest contribution of Popkin’s theory was that it diagnosed a problem exposed by the previous two: the combination of longer lives and chronic illnesses has become unsustainably expensive, and the explanation has a whole lot to do with what we eat. I’ll come back to the nutrition transition after a brief look at the other two.

The term “demographic transition” dates to 1929, when Warren Thompson used it to describe the declining rates of both death and birth in nations where the industrial revolution had taken hold, a characteristic still true for developed and developing nations today. The death rate falls first, thanks to advancements in health care, living conditions, wages, etc. The birth rate then drops gradually as families adjust their reproductive priorities to compensate, a decision facilitated by education, gender equality, and the growing use of contraceptives. The rather simplified explanation [fuller versions here and here] is that the ideal number of grown children per family has always been about two, and until fairly recently several pregnancies were required to ensure two grown children. The precipitous decline of the death rate after 1800 outpaced the adjustment to have fewer pregnancies, leading to large population increases that peaked in the 1960s-70s. Current estimates by the United Nations predict the birth rate will even out with the death rate again sometime around 2300, when the number of people living on this planet would level off at around 9 billion. (There are about 7.35 billion now.)

The “epidemiological transition” dates to 1971, when Abdel Omran described the shift in prevalent diseases from the infectious types (measles, tuberculosis, etc) to the chronic types (cancer, diabetes, etc) that tipped in favor of the latter only recently. Thanks largely to vaccinations and improved hygiene, the modern world has made great progress toward the eradication of many infectious diseases (like smallpox or measles) that used to be extremely lethal. While infectious diseases are often short-term killers, patients with chronic diseases may live for years or decades, affording the afflicted much longer lifespans. (Again, this is the average outcome. Some chronic diseases can be imminently fatal, just as some infectious diseases can develop slowly.) The flip-side to this Faustian bargain is that long-term diseases are much more expensive both for individuals and society. The treatment necessary to survive and thrive with these illnesses doesn’t come cheap, and the longer it takes to get a diagnosis and start treatment the more expensive the treatment becomes. But since we know that human activity causes or exacerbates many of these diseases, modifying our behavior can alleviate both the suffering and the cost.

This brings us to Popkin’s theory of the “nutrition transition”, which the IFPRI describes as the “global trend – whereby consumption of coarse grains, staple cereals, and pulses is replaced by increased consumption of animal-source foods, sugar, fats and oils, refined grains, and processed foods” (p.13 of the full 2017 report). Conventional agriculture (i.e. capitalism) has done a tremendous job of addressing food security worldwide, but the narrow-minded focus on increasing the availability of calories, as opposed to nutrition, has left many communities priced out of a well-balanced diet necessary for good health – at the point of sale, unhealthy food is cheaper than healthy food. To complicate the issue, availability has taken the spotlight away from price, and food deserts have received much of the blame for poor eating habits. But a recent study by the National Bureau of Economic Research (NBER) on the effectiveness of policies aimed at reducing food deserts in the United States (abstract; summary) suggests that factors of demand, such as price and taste, are much more important than proximity when it comes to buying food. We need to find a way to make healthy food cheaper than unhealthy food.

There are many factors contributing to the decline in the price of food in general, and of unhealthy food in particular. Huge international companies are enjoying greater savings due to mass production and price negotiation. Faster and more reliable transportation can now deliver food around the world in order to exploit the cheapest production schemes. Improved technologies from farms to refrigerators have increased yields and decreased spoilage. But one of the most important contributors to cheap and unhealthy food is taxpayer dollars. Government farm subsidies are concentrated on commodity crops like corn and soybean, the same crops that support the meat industry as animal feed, or that get manufactured into countless products found on those lengthy ingredient lists for high-calorie processed foods. Just as we confront a population beset by growing rates of obesity, heart disease, and diabetes, we are focusing our subsidies on the very foods that contribute to these illnesses.

The general consensus now is that the nutrition transition has placed an incredible burden on society, complicating the justification that it has helped to alleviate the problem of food scarcity. Altering our current economic and regulatory approach to the food system can save us trillions of dollars and make us generally more healthy, adding years to our life expectancy. The question, then, is how to effect change. It isn’t enough to rely on individuals to modify their own behavior; a very many people are lured into an unhealthy diet by budget and convenience. Market pressure will improve the situation over time, but the quicker way to address our faltering food system is to incorporate real costs into the marketplace through legislation. We should address the artificially low prices of unhealthy foods by shifting subsidies away from conventional, commodity-oriented agriculture and toward holistic farming methods, such as those that optimize natural inputs and diversified outputs through careful field rotations. We should also levy taxes on certain foods like sugar-sweetened beverages that are known to contribute to obesity, taxes that will help cover the rising costs of health care while steering consumers toward healthier, and more accurately priced, alternatives. Most importantly, we should implement a coherent national food policy that minimizes cost across the economy and maximizes the health of our nation and our world. We can do better. We should demand better.

¹ The percentage of income spent on food decreases as income increases. The average expenditure on food in the United States has now leveled off (at just under 10%) because median incomes haven’t gone up in nearly two decades, according to the Economic Research Service of the USDA.

² The severity of world hunger in the developing world has been reduced by nearly a third since 2000, according to the Global Hunger Index of the IFPRI (International Food Policy Research Institute).