1. Undernutrition and the Dietary Transition
What economics can learn from nutrition, and vice-versa
(Some of)
William A. Masters
Friedman School of Nutrition & Department of Economics, Tufts University |
UC Network on Child Health, Poverty, and Public Policy
6 September 2019

2. Undernutrition and the Dietary Transition
vocabulary | nutrition | economics | conclusions
Undernutrition and the Dietary Transition
What economics can learn from nutrition, and vice-versa
(Some of)
Vocabulary
Some of the many differences of language and professional practice that can limit collaboration and learning
Nutrition
Some facts about dietary intake and health outcomes that I’ve learned, after a decade of teaching in a nutrition school
Economics
Some facts about farm production and food markets that I’ve learned, from 30 years of research in agricultural economics
Conclusions

3. Economists and nutritionists use similar data and similar words,
Undernutrition and the dietary transition
vocabulary | nutrition | economics | conclusions
Economists and nutritionists use similar data and similar words,
but mean very different things
For example, what is “a grant”?
What is “data”?
And what is “a model”?
In clinical nutrition, a model might look like this:
In public-health nutrition, a model might look like this:
The UNICEF framework
(underlying vs proximate causes)
A causal pathways diagram
(left to right, over time)
A social-ecological model
(scale of observation)

4. An individual household A community of farm households
Undernutrition and the dietary transition
vocabulary | nutrition | economics | conclusions
Economists and nutritionists use similar data and similar words,
but mean very different things
For economists, “models” are one or more equations, like these:
In nutrition, these would probably be called “mechanisms”, e.g. the Krebs cycle in nutritional biochemistry
An individual household
(here, a “net seller” of nutritious food)
A community of farm households
(here, they “export” nutritious food)
Qty. of the farm household’s other goods
(kg/yr)
Nutrition:
Diets & behavior
Price of nutritious foods
(pesos/kg)
Agriculture: natural resources and technology
Consumption
Supply
curve
Indifference curve
Production
Price in trade
Production
Consumption
Markets & policy:
Interactions between people
Agriculture: natural resources
and technology
Markets & policy:
Interactions between people
Demand curve
Production possibilities frontier
Nutrition:
Diets & behavior
Price in trade
Qty. of farm household’s nutritious foods (kg/yr)
Qty. of the region’s nutritious foods (tons/yr)

5. Abstracts & presentations
Undernutrition and the dietary transition
vocabulary | nutrition | economics | conclusions
There are big differences between nutrition & economics in professional practices at all stages of research
Some big differences include:
replication & meta-analysis
project selection & planning
pay & working conditions
standards of evidence
statistical methods
authorship & citation
dissemination
uptake of results
Research design
Project funding
Data collection
Data analysis
Abstracts & presentations
Journal publications
Scientific impact
Societal impact
gov’t. agencies
nonprofit orgs.
companies
individuals
motivation
methods
size & scope
personnel
budgets
activities
new observations
proprietary data
public data
results
hyp. tests
variables
abstracts
posters & slides
working papers
gated (subscriber pays)
open access (author pays)
sponsored (funder pays)
citations
data
methods & code
Practices may be driven by outside influences:
Funders
Collaborators
Scientific community
(media & social)
Data sources
Editors & referees
Decision-makers
in organizations
Examples of ways that nutrition differs from economics:
Opening paragraph is about the disease,
not the project
Most work is grant-funded, and work is often delegated to post-docs
Most work follows a stylized protocol, e.g. CONSORT and PRISMA
Results often embargoed in pursuit of press coverage
Many co-authors, first & last author gets most credit;
Primary concern is conflicts of interest (e.g. nutrition.org/ensuringtrust)
Also, increasing focus on transparency and replication, although still less sharing of data and code than in economics
…then methods are spelled out in detail; little focus on novelty
Also, more and shorter papers,
with more citations
(+ role of pubmed)
Economists are also preregistering, e.g. aspredicted.org
Nutritionists can use NutriXiv.org

6. Nutrition and economics have long been interconnected
Undernutrition and the dietary transition
vocabulary | nutrition | economics | conclusions
Nutrition and economics have long been interconnected
“The rich man consumes no more food than his poor neighbour. In quality it may be very different, and to select and prepare it may require more labour and art; but in quantity it is very nearly the same.”
-- Adam Smith (1776), “On the rent of land”, chapter 11 in Wealth of Nations
This is true only
in the short run
The dietary transition towards more and better food,
Nutrient-rich foods (not cereal grains or starchy roots, as a percent of energy)
Dietary transition towards more food per day, bigger people (and more waste?)
as well as shift to fancier foods
Undernutrition remains widespread in some places
Total dietary energy (calories/capita/year)
Data shown are from FAO Food Balance Sheets, Europe includes all of the former Soviet Union.

7. Slides for PIM workshop at ICAE
Undernutrition and the dietary transition
vocabulary | nutrition | economics | conclusions
What Adam Smith got right, and what we’ve learned since then
Metabolic set points make dietary intake roughly isocaloric (me ≈ 2584 kcal/day)
deviations drive change in weight (for me, approx. 24 sodas = 1 lb)
or level of physical activity (for me, approx. 16 min. run ≈ 1 soda)
also change with body composition & disease (age, height, gut health)
Improved diets + sanitation leads to taller, bigger people
stunting below potential height mostly occurs before age 2, rarely reversed
weight gain through fat deposition occurs gradually, very difficult to reverse
As other risks decline, diets have become world’s #1 health risk factor
persistence of undernutrition and nutrient deficiencies, especially in early life
dietary transition drives obesity, cardiometabolic & other risks in later life
key health attributes are invisible, discovered gradually by nutrition science
new foods with limited history are especially prone to information failures
Hall et al 2011 ( IOM 2006; Tooze et al. 2007; Shetty 2005; MyPlate 2018

8. Slides for PIM workshop at ICAE
Undernutrition and the dietary transition
vocabulary | nutrition | economics | conclusions
What have nutritionists discovered?
Nutritional discoveries trace the history of science
limes prevent scurvy (J. Lind in Britain, 1747)
food contains energy (A. Lavoisier in France, 1770)
boiling & sealing preserves food (N. Appert in France, 1810)
energy can be protein, fats or carbs (J. Liebig in Germany, 1840)
germ theory & pasteurization of milk (L. Pasteur in France, 1864)
“vitamines” must exist, because rice husks prevent beriberi (1912)
vitamin C is first to be isolated, shown to prevent scurvy (1936)
Nutritional discoveries have driven government intervention
nutrient adequacy was focus of first dietary guidelines (1941)
epidemiological data demonstrates additional role of food groups (1990s)
fruits & vegetables first separated out in U.S. dietary guidelines (2000)
trans fats found harmful, mandatory disclosure (2006) then removal (2015)
Mozaffarian, Rosenberg and Uauy 2018

9. In a very poor country (Malawi), what undernutrition is most severe?
Undernutrition and the dietary transition
vocabulary | nutrition | economics | conclusions
In a very poor country (Malawi), what undernutrition is most severe?
Data on individuals’ intake is very scarce and expensive, so we use household data instead
We add up all household members’ requirements for a healthy & active life in terms of 21 essential nutrients, which vary by age, sex, pregnancy and breastfeeding
We assume that individuals share the family diet in proportion to energy balance
The most severe deficits in this context are for zinc, riboflavin, selenium and vitamin B12
These nutrients have a variety of functions, and are often supplied by animal-sourced foods
Some gaps can be filled through fortification, but currently only for Vitamin A (in sugar & cooking oil)
The most under-consumed nutrients include total fats, some vitamins and minerals
Edited to ensure that the text matches the figure, and that the chart is self-explanatory
Source: CANDASA project results, from Schneider et al. (2019)

10. Slides for PIM workshop at ICAE
Undernutrition and the dietary transition
vocabulary | nutrition | economics | conclusions
Economic mechanisms driving nutrition and dietary transition
Income growth and safety nets, in cash or in kind
Relative prices and convenience, for healthier vs. less healthy items
Knowledge, norms and beliefs, among all options at home and away
Standards and regulation, to address information failures
For example:
Britain creates Assize of Bread and Ale for quality & weight (1266)
U.S. creates the FDA & has USDA inspect meat (from 1906)
Supreme Court rules against false advertising (vinegar, in 1924)
FDA sets first packaged food standard (canned tomatoes, in 1939)
FDA defines and regulates additives, creates GRAS list (in 1958)
Organic standards introduced (in 1990)
Nutrient fact panels introduced (in 1993 for packaged foods, 2018 for menus)
Harmful nutrients disclosed then removed (e.g. trans fats, from 2006)
Ross 1956; FDA 2018

11. The role of agricultural economics in nutrition and dietary transition
Undernutrition and the dietary transition
vocabulary | nutrition | economics | conclusions
The role of agricultural economics in nutrition and dietary transition
In economic development, farms remain household enterprises,
but input supply and the food industry
have employees & scale economies
Agriculture-nutrition linkages are asymmetric
Input supply
Farms & agribusinesses
provide food commodities, so can help end undernutrition through higher farm income and lower food prices
Most of the world’s undernutrition occurs in farm families
Family farms
With access to markets, food consumption becomes separable from food production
Food companies
transform commodities and other inputs into products, like any manufacturing sector
Food
industry
Food consumers

12. Slides for PIM workshop at ICAE
Undernutrition and the dietary transition
vocabulary | nutrition | economics | conclusions
The Malthusian aspect of rural poverty follows rural population growth
Number of people (billions)
Africa’s rising rural population keeps workers in agriculture,
and keeps children in poverty, until farming conditions improve
After each turning point,
those remaining in rural areas
can expand land use per farm household
(The U.S. peak was around 1914,
after which falling rural populations and rising farm sizes continued until 1990s)
Data shown are author’s calculations from UN World Urbanization Prospects, 2014 Revision, from

13. Slides for PIM workshop at ICAE
Undernutrition and the dietary transition
vocabulary | nutrition | economics | conclusions
Africa’s fast rural population growth keeps most of its workers on farms
Share of all workers in each country
working in
agricuture
(percent)
1991 (green circles)
2010 (blue squares)
African countries
At each level of national income, agriculture employs a larger share
of workers in Africa than in other regions
All other countries
…and at each income level,
there was no shift from 1990s to 2010s
These are “Preston curves”, showing national averages at each level of per-capita income
Source: Reprinted from W.A. Masters, N.Z. Rosenblum and R.G. Alemu, Agricultural transformation, nutrition transition and food policy in Africa. Journal of Development Studies, 54(5): Employment data are ILO (2015), national income is from World Bank (2018).

14. Slides for PIM workshop at ICAE
Undernutrition and the dietary transition
vocabulary | nutrition | economics | conclusions
African children are more likely to be stunted, but big gains over time
Share of all children in each country who are stunted,
WHZ<-2
(percent)
1990s (green circles)
2010s (blue squares)
At each level of national income, stunting rates are higher in Africa than in other regions
African countries
…but that fraction has shifted down, due to innovation in child health
All other countries
Source: Reprinted from W.A. Masters, N.Z. Rosenblum and R.G. Alemu, Agricultural transformation, nutrition transition and food policy in Africa. Journal of Development Studies, 54(5): Stunting are World Bank, WHO and UNICEF joint data, national income is from World Bank (2018).

15. Slides for PIM workshop at ICAE
Undernutrition and the dietary transition
vocabulary | nutrition | economics | conclusions
In Africa, there is more obesity in higher-income countries
Share of all
adults aged 20+
in each country,
BMI>30
(percent)
African countries
All other countries
In Africa, there is a strong income gradient and little upward shift in obesity prevalence at each income level, at least by 2010
From 1990 to 2010, there was a shift up at each income level in richer countries
2010 (blue squares)
1990 (green circles)
Source: Reprinted from W.A. Masters, N.Z. Rosenblum and R.G. Alemu, Agricultural transformation, nutrition transition and food policy in Africa. Journal of Development Studies, 54(5): Obesity is from Global Burden of Disease study, national income is from World Bank (2018).

16. The dietary transition involves rising levels of packaged food sales
Undernutrition and the dietary transition
vocabulary | nutrition | economics | conclusions
The dietary transition involves rising levels of packaged food sales
Packaged food sales (kcal/person/day) by level of national income,
GNI per capita, PPP (constant 2011 US dollars), log scale
Source: Packaged food sales are estimated by Euromonitor, and are available for the 54 countries shown. National income is GNI per capita in constant US dollars at 2011 PPP prices. Darker dots show later years.

17. Slides for PIM workshop at ICAE
Undernutrition and the dietary transition
vocabulary | nutrition | economics | conclusions
Relative prices for food are lower at higher levels of national income
Average price level for household expenditure in national accounts, 2011
High cost in poor countries could be due to low productivity of local food systems, and international competition for traded goods
GNI per capita, PPP (constant 2011 US dollars), log scale
Source: Author’s calculations, from World Bank, International Comparison Program (ICP) data for the CANDASA project (
Note: Data shown are average prices for goods & services in selected sectors, relative to that sector’s price level in the U.S., at each level of national income per capita measured at purchasing power parity prices in 2011, estimated by local polynomial regression for 159 countries.

18. Slides for PIM workshop at ICAE
Undernutrition and the dietary transition
vocabulary | nutrition | economics | conclusions
Price indexes for the cost of nutritious foods reveal food system change
The CANDASA project uses price data to calculate alternatives to the CPI
based on nutritional value
Cost of Nutrient Adequacy (CoNA)
From Dietary Reference Intakes for 21 macro- and micro-nutrients
-- Use a total of 35 upper and lower limits for intake (e.g. mcg/day)
Select least-cost foods to provide nutrients in required proportions
-- Results use 6-8 items at each place and time to meet all constraints
Cost of Recommended Diets (CoRD)
From Dietary Guidelines for quantity consumed from each food group
-- Use target quantities of foods in each group (e.g. servings/day)
Select least-cost foods from each group in required proportions
-- Results use 6-8 items, with more expensive foods than CoNA
Nutritionally-weighted Consumer Price Index (nCPI)
Use Nutrient Profile scores for each food’s contribution to health
Count all foods in the CPI basket, with nutritional weights

19. Food price trends differ greatly by food group
Undernutrition and the dietary transition
vocabulary | nutrition | economics | conclusions
Food price trends differ greatly by food group
Using prices for 92 items at 120 markets in all regions of Ethiopia, monthly from 2001 to 2017
Falling prices for
green revolution crops
Rising prices for nutrient-rich foods
Seasonal patterns and trends differ by food group
Source: CANDASA project results from F. Bachewe et al. (2019)

20. The cost of nutrient adequacy varies but often above poverty lines
Undernutrition and the dietary transition
vocabulary | nutrition | economics | conclusions
The cost of nutrient adequacy varies but often above poverty lines
Using prices for 55 items at 29 markets in all regions of Malawi every month for , and their nutrient contents from the new Food Composition Table (FCT) for Malawi
plus all Dietary Reference Intake (DRI) constraints, we find:
Expense is highest in pregnancy and lactation; Well above local and global poverty lines
Cost per day
(US$ at 2011 PPP prices)
Cost per 1,000 kcal
(US$ at 2011 PPP prices)
A more expensive mix of foods is needed for children, adolescent girls, women and the elderly
$1.90
$1.50
Source: CANDASA project results from Y. Bai et al. (2019)

21. Overall diet costs have complex patterns of seasonality
Undernutrition and the dietary transition
vocabulary | nutrition | economics | conclusions
Overall diet costs have complex patterns of seasonality
Using prices for 64 items at 21 markets in all regions of Tanzania, monthly from 2011 to 2015, with nutrient composition and all Dietary Reference Intake (DRI) constraints for a representative adult woman
Seasonality varies by type of food
Seasonality in diet cost varies by region
Starchy staples
Pulses
Animal foods
Fruits and veg.
Width shows estimated period of higher prices
Dark dots show statistically significant peaks
Colors show magnitude of seasonal rise
Animal foods
(and processed foods)
have the least seasonality
Fruits and vegetables have the most seasonality, and also variation in peak timing
Source: CANDASA project results from Y. Bai et al. (2019)

22. Conclusions: international nutrition can inform US policy
Undernutrition and the dietary transition
vocabulary | nutrition | economics | conclusions
Conclusions: international nutrition can inform US policy
Agriculture drives end to undernutrition, but the food industry drives dietary transition
In poor rural areas, low farm incomes and high food prices are linked to persistent undernutrition
With economic development, shift to packaged foods involves information failure
Food is increasingly regulated like other manufacturing sectors (e.g. vehicle safety, fire codes etc.)
Poverty-related deficits in early childhood are followed by excesses in later life
Public services for pregnancy and infancy, then information and regulation for adult nutrition
Many foods and nutrients have U-shaped risk curves, calling for Goldilocks nutrition
=> Food markets and food policies are very sensitive to nutrition research findings
Nutritionists and economists have much more to learn from each other
Barriers to collaboration remain high, due to big differences of language and professional practices
The two domains are highly complementary, but paradigm shifts are required
For economists, recognizing that food is a manufacturing sector with information failures
For nutritionists, recognizing that diets depend on consumer choice and market equilibrium
=> Many opportunities for work ahead!