Understanding the Nutrition Transition (and what we can do about it)


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. Caesar: Von Cassius has a lean and hungry look, would he were fatter. Brutus: Feed him on Libby, McNeill & Libby's Cooked Corned Beef. Caesar: Ay, do so, good Brutus, let us have only men about us that are fat. [front]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.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).

Obesity – a review

Line-graph showing the average calories consumed per day by Americans from 1970 to 2010

From Sturm, R. and An, R. (2014), Obesity and economic environments. CA: A Cancer Journal for Clinicians, 64: 337–350. doi:10.3322/caac.21237

One of the main contributors to the rising costs of health care is obesity. In 2014, CA published a report called “Obesity and economic environments” that addresses what factors lead to obesity. The authors focus largely on what they call “economic and policy environments”, which is basically any government intervention that shows up when a consumer purchases a product, such as a tax or a subsidy, a limit on serving size, a nutrition label, etc. (These are distinguished from “social environments” -factors influencing a consumer’s choice in food purchases- and “physical environments” -opportunities for consumers to expend energy.) Here is a review of the report’s highlights and conclusions. Recognizing that this information is now 3 years old, I’ll follow up on some of the main points and update as needed.

First, the report makes a few fundamental observations worth noting:

  • Obesity increases the risk of at least 9 different types of cancer, in addition to coronary heart disease, type 2 diabetes, hypertension, stroke, and other chronic illnesses.
  • In developed countries, obesity is by far a greater problem than food scarcity.
  • “Americans now have the cheapest food in history when measured as a fraction of disposable income.” Less than a century ago, Americans spent 25% of their income on food. Now it’s less than 10% (even while the bottom fifth of American incomes still spend a third).
  • Americans have increased their number of calories consumed per day by more than 20% in less than 50 years, going from about 2100 calories per day in 1970 to more than 2600 in the mid-2000s, and dropping only slightly since then.
  • The greatest single source of the increased calories since 1980 has been carbohydrates. Only recently have carbs shown a decline, being replaced by fats.
  • SSB (sugar-sweetened beverage) consumption continues to go up, both in the number of people drinking them and the amount each person drinks.
  • Policies of the USDA have created “a vicious cycle” of encouraging “a massive overproduction of corn and soybeans”, slashing the prices (and thus increasing consumption) of derivative products, many of which show up on those lengthy ingredient lists for processed, prepackaged foods.

Second, the report confronts some common assumptions related to the obesity epidemic that are either too simplistic or flat out wrong.

  • A sedentary lifestyle is not on the rise: The Centers for Disease Control and Prevention Behavioral Risk Factor Surveillance System (BRFSS) “has demonstrated a consistent decline in sedentary behavior.”
  • Leisure-time physical activity has risen, not fallen.
  • Fruits and vegetables have actually increased in the American diet since 1970, even though they still remain below the recommended levels.
  • Locating “food deserts” is not a very accurate way of determining consumption habits of the people in those communities. “Across numerous studies, distance to various types of food stores demonstrated no relationship to dietary outcomes.” This study argues that the real issue is poverty, not access (the study is reviewed here and here). Furthermore, the idea that supermarkets create healthy environments “is a unique United States concept. Elsewhere, the growth of supermarkets has been deplored as reducing access to fruits and vegetables and even increasing prices for fresh produce” because they often take the place of stores dedicated to fruits or vegetables rather than processed, prepackaged foods. Individual cases of obesity can be attributed to one’s access to healthy foods, but the overall rate of incidence for obesity has no such correlation.

Finally, the conclusions. Many of the ideas floating around in the gastrosphere on how to combat the obesity epidemic are either wrong or insufficiently supported by evidence; in the case of the latter, further studies might show support, or might not. What we do know (or did know in 2014), is this…

“Based on empirical evidence and expert opinion, 3 recommendations have been supported by a broad group of health economists in the obesity area:

  1. incorporate health impact assessments to review agricultural policies so that they do not have a deleterious impact on population rates of obesity;
  2. implement a tax on SSB;
  3. examine how to implement fruit and vegetable subsidies targeted at children and low-income households.”

So while it may not be “politically feasible” to institute a national food policy that covers farm to cash register, or to levy taxes on sodas, or to create higher nutritional standards for school lunches, these are the types of things that show promise in addressing the obesity epidemic. What seems clear from the available evidence is that there are too many variables in the national diet for personal choice to make the shift without a policy nudge. Better nutrition saves lives and money. Contact your elected officials and support evidence-based improvements to our food system.

The health of our food system

junk-food-brainThis post will lay out (what I understand to be) the basic logic behind why consuming a varied diet of whole foods cooked yourself is more desirable than a “conventional” diet of processed, packaged, or prepared foods. In sum, what you eat is a major determinant of your health cost; that is, the financial burden of your medical needs. It is an ironie du sort that taxpayers are the very ones who make the least healthy foods the cheapest to eat, thanks to corporate lobbyists. This is why the discussion of food is political rather than merely personal. The argument consists of an extremely complicated set of issues, and although some points will be more obvious than others, each and every one deserves its own post, researched and cited. As that work is done, I’ll update this post with the appropriate links, and corrections when necessary.

It must be said that there are many variables that affect our health for which we have little to no control, from genetic predisposition to environmental exposure to accidental injury. The one aspect of our health that we can control is our diet, although even here there are factors that restrict our ability to choose, such as budget, tradition, and availability. I hope to have the opportunity to expand my coverage at some point, but the focus of this argument is two-fold: to show why a more natural diet is optimal for our health, and to recognize that the current food system encourages eating habits that are patently detrimental to our health.

  1. Good health is intrinsically connected to nutrition (although nutrition is not the only component of good health). Furthermore, diet is responsible for more ailments than we generally acknowledge.
  2. We house a vital community of bacteria in our gut, commonly referred to as the intestinal microbiome. I’ve come to refer to these critters endearingly as “gut buggies”. The makeup of this community depends on the nourishment it receives, which is determined by the foods we eat. A more complex diet leads to a more complex community of gut buggies.
  3. These gut buggies contribute to the breaking down of food in the process of digestion. A more complex community of gut buggies means a larger variety of nutritive elements made available for use by the body.
  4. Without venturing a numerical guess, good nutrition requires more essential elements than we have isolated so far. In much the same way as it is hubris to discount the possible existence of life elsewhere in the universe, or even our own galaxy, it is hubris to think we have mastered the elements of nutrition. A varied diet built upon whole foods is preferable because it exposes us to the still unknown complexities of nature rather than to the limited consistency required of factory mass production.
  5. Currently, the subsidies provided by our tax dollars prioritize calories over nutrition.
  6. Highly processed foods – primarily, those artificially loaded with salt, sugar, and/or fat in order to create addictive bliss points – tend to have lots of ingredients but are actually less complex in terms of nutrition because many of the ingredients that go into these products start from just two sources: corn and soybean.
  7. Highly processed foods are a leading cause of poor nutrition in the developed world. This problem is compounded by the relative low price of these foods compared to whole, raw foods, a phenomenon supported by those government subsidies.
  8. Poor nutrition contributes to many long-term health problems, to include heart disease and type 2 diabetes (two of the leading causes of death in the developed world).
  9. Eating more whole foods is cheaper in the long run. Changing the way we subsidize our food system will improve our health and will reduce the burdensome costs of health care.
  10. I am not advocating for the complete abolition of any particular type of food. Put simply, our food system should encourage foods that are more healthy and discourage foods that are less healthy. Current subsidies in our food system lead to higher long-term health costs than necessary, which is detrimental to our economy, our society, and our culture.