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WORKING PAPER | April 2016 | 1
WORKING PAPER
JANET RANGANATHAN, DANIEL VENNARD, RICHARD WAITE, PATRICE DUMAS,
BRIAN LIPINSKI, TIM SEARCHINGER, AND GLOBAGRI-WRR MODEL AUTHORS
CONTENTS
Summary...........................................................................1
Diet Matters on the Menu................................................14
Converging Diets........................................................ .... 21
Diet Shift 1: Reduce Overconsumption of Calories......... 25
Diet Shift 2: Reduce Overconsumption of Protein by
Reducing Consumption of Animal-Based Foods.............31
Diet Shift 3: Shift from Beef Specifically..........................42
Effects of the Diet Shifts in 2050................................. ....49
Shifting Strategies for Shifting Diets................................50
Shift Wheel: A Framework for Shifting Consumption......... 52
Recommendations...........................................................63
Call to Action...................................................................65
Appendices......................................................................66
References.......................................................................73
Endnotes..........................................................................82
Working Papers contain preliminary research, analysis,
ndings, and recommendations. They are circulated to
stimulate timely discussion and critical feedback, and to
inuence ongoing debate on emerging issues. Working
papers may eventually be published in another form and
their content may be revised.
Suggested Citation: Ranganathan, J. et al. 2016.
“Shifting Diets for a Sustainable Food Future.” Working Paper,
Installment 11 of Creating a Sustainable Food Future.
Washington, DC: World Resources Institute. Accessible at
http://www.worldresourcesreport.org.
SUMMARY
How can shifting diets—the type, combination, and
quantity of foods people consume—contribute to a
sustainable food future? Building on the United Nations
Food and Agriculture Organization’s (FAO) food demand
projections, we estimate that the world needs to close a 70
percent “food gap” between the crop calories available in
2006 and expected calorie demand in 2050.
The food gap stems primarily from population growth
and changing diets. The global population is projected to
grow to nearly 10 billion people by 2050, with two-thirds
of those people projected to live in cities. In addition,
at least 3 billion people are expected to join the global
middle class by 2030. As nations urbanize and citizens
become wealthier, people generally increase their calorie
intake and the share of resource-intensive foods—such
as meats and dairy—in their diets. At the same time,
technological advances, business and economic changes,
and government policies are transforming entire food
chains, from farm to fork. Multinational businesses are
increasingly inuencing what is grown and what people
eat. Together, these trends are driving a convergence
toward Western-style diets, which are high in calories,
protein, and animal-based foods. Although some of this
shift reects health and welfare gains for many people,
the scale of this convergence in diets will make it harder
for the world to achieve several of the United Nations
Sustainable Development Goals, including those on
hunger, healthy lives, water management, climate change,
and terrestrial ecosystems.
Installment 11 of “Creating a Sustainable Food Future”
SHIFTING DIETS FOR A
SUSTAINABLE FOOD FUTURE
Note:
All dollars are US dollars. All tons are metric tons (1,000 kg). “GHG” = greenhouse gas.
“CO2e” = carbon dioxide equivalent. “Kcal” = kilocalorie, also referred to as simply “calorie.”
EMBARGOED FOR 4.20.16
AT 12:01 AM EDT.
2 |
Eorts to close the food gap have typically focused on
increasing agricultural production. However, relying solely
on increased production to close the gap would exert pres-
sure to clear additional natural ecosystems. For example,
to increase food production by 70 percent while avoiding
further expansion of harvested area, crop yields would
need to grow one-third more quickly than they did during
the Green Revolution. In short, yield increases alone will
likely be insucient to close the gap.
To help provide a more holistic approach, the World
Resources Report, Creating a Sustainable Food Future,
and a series of accompanying working papers propose a
menu of production- and consumption-based solutions. In
this paper, the last in the series, we assess the role of one
consumption-based solution: shifting the diets of popula-
tions who consume high amounts of calories, protein,
and animal-based foods. Specically, we consider three
interconnected diet shifts:
1. Reduce overconsumption of calories.
2. Reduce overconsumption of protein by reducing
consumption of animal-based foods.
3. Reduce consumption of beef specically.
For each shift, we describe the issue it addresses, why it
matters, and the relevant trends. We use the GlobAgri
model to quantify the land use and greenhouse gas
consequences of dierent foods, and then analyze the
per person and global eects of the three diet shifts on
agricultural land needs and greenhouse gas emissions.
We nd that these diet shifts—if implemented at a
large scale—can close the food gap by up to 30 percent,
while substantially reducing agriculture’s resource use
and environmental impacts. With the food industry in
mind—particularly the retail and food service sectors—we
introduce the Shift Wheel, a framework that harnesses
marketing and behavioral change strategies to tackle
the crucial question of how to shift people’s diets. We
conclude with four recommendations to help shift diets
and apply the Shift Wheel.
What are the trends in calorie consumption and
why do they matter?
There is a global trend toward overconsumption of
calories, even though many people around the world
remain hungry. In 2009, per capita calorie consumption
exceeded average daily energy requirements in regions
containing half of the world’s population. Globally, there
are now two-and-a-half times more overweight than
undernourished people. More than one in three adults
are overweight. While per person calorie availability may
be peaking in developed countries, it is rising across the
developing world, particularly in emerging economies like
China and Brazil. Once considered a high-income-country
problem, the numbers of obese or overweight people are
now rising in low- and middle-income countries, espe-
cially in urban areas.
Overconsumption of calories widens the food gap and
drives unnecessary use of agriculture inputs and unnec-
essary environmental impacts. It also contributes to
people becoming overweight and obese, harming human
health and contributing to rising healthcare costs and lost
productivity. The related economic and healthcare costs
are enormous. For example, the global economic cost of
obesity was estimated to be around $2 trillion in 2012,
roughly equivalent to the global cost of armed conict or
smoking.
What are the trends in protein consumption
and why do they matter?
Overconsumption of protein occurs in all of the world’s
regions, and it is rising in developing and emerging econo-
mies. In 2009, the average person in more than 90 percent
of the world’s countries and territories consumed more
protein than estimated requirements. Global average pro-
tein consumption was approximately 68 grams per person
per day—or more than one-third higher than the average
daily adult requirement. In the world’s wealthiest regions,
protein consumption was higher still (Figure ES-1).
In addition, the share of animal-based protein is grow-
ing in people’s diets relative to that of plant-based pro-
tein. Between 1961 and 2009, global average per person
availability of animal-based protein grew by 59 percent,
while that of plant-based protein grew by only 14 percent.
Looking forward, total consumption of animal-based food
is expected to rise by nearly 80 percent between 2006
WORKING PAPER | April 2016 | 3
Shifting Diets for a Sustainable Food Future
Figure ES–1 | Protein Consumption Exceeds Average Estimated Daily Requirements in
All the World’s Regions, and is Highest in Developed Countries
g/capita/day, 2009
and 2050. Although per person animal-based food con-
sumption may be peaking in developed countries where
consumption is already high, it is projected to rise in
developing countries, especially in emerging economies
and in urban areas.
Like overconsumption of calories, overconsumption
of protein widens the food gap. Furthermore, animal-
based foods are typically more resource-intensive and
environmentally impactful to produce than plant-based
foods (Figure ES-2). Production of animal-based foods
accounted for more than three-quarters of global agri-
cultural land use and around two-thirds of agriculture’s
production-related greenhouse gas emissions in 2009,
while only contributing 37 percent of total protein con-
sumed by people in that year. Because many animal-based
foods rely on crops for feed, increased demand for animal-
based foods widens the food gap relative to increased
demand for plant-based foods.
What are the trends in beef consumption and
why do they matter?
Beef consumption is rising in emerging economies and is
showing signs of peaking in some developed countries. In
Brazil, per person beef availability (and probably con-
sumption) has increased steadily over the past decades,
and is now more than three times the world average,
having surpassed the United States in 2008. In China, per
person beef availability is still only half of the world aver-
age, but is growing. In India, growing demand for dairy
products is spurring an expansion in the cattle population,
although beef consumption remains low. In the United
States, per person annual beef consumption has declined
27 percent since the 1970s. Global demand for beef is pro-
jected to increase by 95 percent between 2006 and 2050,
with much of this growth in countries where current per
person consumption is low, such as China and India.
Population (billions)
Animal-based protein
Plant-based protein
Average daily
protein requirement
0
10
20
30
40
50
60
70
80
90
100
01234567
India Asia
(ex. China & India)
Sub-Saharan
Africa
Latin America
(ex. Brazil)
China Middle East &
North Africa
European
Union
Former
Soviet Union
OECD (other) Brazil US & Canada
Source:
GlobAgri model with source data from FAO (2015) and FAO (2011a). Width of bars is proportional to each region’s population. Average daily protein requirement of 50 g/day is based
on an average adult body weight of 62 kg (Walpole et al. 2012) and recommended protein intake of 0.8 g/kg body weight/day (Paul 1989). Individuals’ energy requirements vary depending on
age, gender, height, weight, pregnancy/lactation, and level of physical activity.
4 |
Figure ES-2 | Production of Animal-Based Foods is Generally
More Impactful on the Planet than Plant-Based Foods
Sources:
GlobAgri model (land use and greenhouse gas emissions), authors’ calculations from Mekonnen and Hoekstra (2011, 2012) (freshwater consumption), and Waite et al. (2014)
(farmed fish freshwater consumption).
Notes:
Data presented are global means. Entries are ordered left to right by amount of total land use. Indicators for animal-based foods include resource use to produce feed, including pasture.
Tons of harvested products were conver ted to quantities of calories and protein using the global average edible calorie and protein contents of food types as reported in FAO (2015). “Fish”
includes all aquatic animal products. Freshwater use for farmed fish products is shown as rainwater and irrigation combined. Land use and greenhouse gas emissions estimates are based on
a marginal analysis (i.e., additional agricultural land use and emissions per additional million calories or ton of protein consumed). Based on the approach taken by the European Union for
estimating emissions from land-use change for biofuels, land-use change impacts are amortized over a period of 20 years and then shown as annual impacts. Land use and greenhouse gas
emissions estimates for beef production are based on dedicated beef production, not beef that is a coproduct of dairy. Dairy figures are lower in GlobAgri than some other models because
GlobAgri assumes that beef produced by dairy systems displaces beef produced by dedicated beef-production systems.
0
30
60
90
120
150
180
PROTEIN CONSUMED CALORIE CONSUMED
Pulses Fish
(farmed)
EggsPork Poultry Dairy Beef
LAND USE (ha)
Pasture
Cropland
GHG EMISSIONS (t CO2e)
Land-use change
Agricultural production
FRESHWATER CONSUMPTION (1,000 m3)
Rainwater
Irrigation
ANIMAL-BASEDPLANT-BASED
PER TON PROTEIN CONSUMED PER MILLION KILOCALORIES CONSUMED
Wheat Soybean Oil Fruits &
Vegetables
Sunflower
Seed Oil
Rice Rapeseed
& Mustard
Seed Oil
Sugar Maize PulsesRoots &
Tubers
Fish
(farmed)
EggsPork Poultry Dairy Beef
LAND USE (ha)
Pasture
Cropland
GHG EMISSIONS (t CO2e)
Land-use change
Agricultural production
FRESHWATER CONSUMPTION (1,000 m3)
Rainwater
Irrigation
ANIMAL-BASEDPLANT-BASED
Rice Maize Roots &
Tubers
Wheat
0
3
6
9
12
15
ha
120 3,000
1,000 m3 t CO2e
100 2,500
80 2,000
60 1,500
40 1,000
20 500
ha 1,000 m3 t CO2e
10 250
8200
6150
4100
250
WORKING PAPER | April 2016 | 5
Shifting Diets for a Sustainable Food Future
Figure ES-2 | Production of Animal-Based Foods is Generally
More Impactful on the Planet than Plant-Based Foods (continued)
Sources:
GlobAgri model (land use and greenhouse gas emissions), authors’ calculations from Mekonnen and Hoekstra (2011, 2012) (freshwater consumption), and Waite et al. (2014)
(farmed fish freshwater consumption).
Notes:
Data presented are global means. Entries are ordered left to right by amount of total land use. Indicators for animal-based foods include resource use to produce feed, including pasture.
Tons of harvested products were conver ted to quantities of calories and protein using the global average edible calorie and protein contents of food types as reported in FAO (2015). “Fish”
includes all aquatic animal products. Freshwater use for farmed fish products is shown as rainwater and irrigation combined. Land use and greenhouse gas emissions estimates are based on
a marginal analysis (i.e., additional agricultural land use and emissions per additional million calories or ton of protein consumed). Based on the approach taken by the European Union for
estimating emissions from land-use change for biofuels, land-use change impacts are amortized over a period of 20 years and then shown as annual impacts. Land use and greenhouse gas
emissions estimates for beef production are based on dedicated beef production, not beef that is a coproduct of dairy. Dairy figures are lower in GlobAgri than some other models because
GlobAgri assumes that beef produced by dairy systems displaces beef produced by dedicated beef-production systems.
0
30
60
90
120
150
180
PROTEIN CONSUMED CALORIE CONSUMED
Pulses Fish
(farmed)
EggsPork Poultry Dairy Beef
LAND USE (ha)
Pasture
Cropland
GHG EMISSIONS (t CO2e)
Land-use change
Agricultural production
FRESHWATER CONSUMPTION (1,000 m3)
Rainwater
Irrigation
ANIMAL-BASEDPLANT-BASED
PER TON PROTEIN CONSUMED PER MILLION KILOCALORIES CONSUMED
Wheat Soybean Oil Fruits &
Vegetables
Sunflower
Seed Oil
Rice Rapeseed
& Mustard
Seed Oil
Sugar Maize PulsesRoots &
Tubers
Fish
(farmed)
EggsPork Poultry Dairy Beef
LAND USE (ha)
Pasture
Cropland
GHG EMISSIONS (t CO2e)
Land-use change
Agricultural production
FRESHWATER CONSUMPTION (1,000 m3)
Rainwater
Irrigation
ANIMAL-BASEDPLANT-BASED
Rice Maize Roots &
Tubers
Wheat
0
3
6
9
12
15
ha
120 3,000
1,000 m3 t CO2e
100 2,500
80 2,000
60 1,500
40 1,000
20 500
ha 1,000 m3 t CO2e
10 250
8200
6150
4100
250
6 |
SCENARIO NAME SCENARIO DESCRIPTION AFFECTED POPULATION
(MILLIONS), 2009
DIET SHIFT 1: Reduce overconsumption of calories
Eliminate Obesity and
Halve Overweight
Recognizing that reducing overconsumption of calories can contribute to reducing overweight
and obesity, this scenario eliminates obesity and halves the number of overweight people by
reducing calorie consumption across all foods.
1,385
Halve Obesity and
Halve Overweight
Similar to the above scenario, this scenario halves the number of obese and
overweight people.
1,046
DIET SHIFT 2: Reduce overconsumption of protein by reducing consumption of animal-based foods
Ambitious Animal
Protein Reduction
In regions that consumed more than 60 grams of protein (from animal and plant sources
combined) and more than 2,500 calories per person per day, protein consumption was reduced to
60 grams per person per day by reducing animal-based protein consumption (across all animal-
based foods). Overall, global animal-based protein consumption was reduced by 17 percent.
1,907
Traditional
Mediterranean Diet
In regions that consumed more than 40 grams of animal-based protein and more than 2,500
calories per person per day, half of the population was shifted to the actual average diet of Spain
and Greece in 1980. Overall calorie consumption was held constant.
437
Vegetarian Diet In regions that consumed more than 40 grams of animal-based protein and more than 2,500
calories per person per day, half of the population was shifted to the actual vegetarian diet as
observed in the United Kingdom in the 1990s. Overall calorie consumption was held constant.
437
DIET SHIFT 3: Reduce beef consumption specifically
Ambitious Beef
Reduction
In regions where daily per person beef consumption was above the world average and daily per
person calorie consumption was above 2,500 per day, beef consumption was reduced to the
world average level. Overall, global beef consumption was reduced by 30 percent.
1,463
Shift from Beef to
Pork and Poultry
In regions where daily per person beef consumption was above the world average, beef
consumption was reduced by one-third and replaced by pork and poultry. Overall calorie
consumption was held constant.
1,952
Shift from Beef to
Legumes
In regions where daily per person beef consumption was above the world average, beef
consumption was reduced by one-third and replaced with pulses and soy. Overall calorie
consumption was held constant.
1,952
Table ES-1 | Diet Shifts and Scenarios Modeled in this Paper
Beef is one of the least ecient foods to produce when
considered from a “feed input to food output” perspective.
When accounting for all feeds, including both crops and
forages, by one estimate only 1 percent of gross cattle feed
calories and 4 percent of ingested protein are converted
to human-edible calories and protein, respectively. In
comparison, by this estimate, poultry convert 11 percent of
feed calories and 20 percent of feed protein into human-
edible calories and protein. Because of this low conversion
eciency, beef uses more land and freshwater and generates
more greenhouse gas emissions per unit of protein than any
other commonly consumed food (Figure ES-2).
At the global level, beef production is a major driver of
agricultural resource use. One-quarter of the Earth’s
landmass, excluding Antarctica, is used as pasture, and
beef accounts for one-third of the global water footprint
of farm animal production. Although some beef produc-
tion uses native pasture, increases in beef production now
rely on clearing forests and woody savannas. Ruminants,
of which beef is the most commonly produced and con-
sumed, are responsible for nearly half of greenhouse gas
emissions from agricultural production. Given the envi-
ronmental implications of rising demand for beef, reduc-
ing its consumption will likely be an important element to
limiting the rise of global temperatures to 1.5 or 2 degrees
Celsius, in line with international goals.
WORKING PAPER | April 2016 | 7
Shifting Diets for a Sustainable Food Future
What would be the effects of applying the three
diet shifts to high-consuming populations?
Shifting the diets of high-consuming populations could
signicantly reduce agricultural resource use and
environmental impacts. We used the GlobAgri model to
analyze the eects of the three diet shifts on agricultural
land use and greenhouse gas emissions in 2009. For each
of the three shifts, we developed alternative diet scenarios,
ranging from “realistic” to “ambitious” (Table ES-1). In
each scenario, we assumed that crop and livestock yields
and trade patterns remained constant at actual 2009
levels. We altered food consumption levels among the
world’s high-consuming populations, but did not alter the
diets of the world’s less wealthy. None of the scenarios
sought to turn everyone into a vegetarian.
We conducted two types of analysis using 2009 food
consumption data:
▪First, we quantied the per person eects of applying
the diet scenarios in Table ES-1 to the consumption
pattern of a high-consuming country—the United
States (Figure ES-3). This analysis shows how, among
high-consuming populations, the three diet shifts
could signicantly reduce per person agricultural land
use and greenhouse gas emissions.
▪Second, we quantied the global eects of applying the
diet scenarios to people currently overconsuming calo-
ries or protein, or who are high consumers of beef, to
show the aggregate eects of the diet shifts across large
populations. The scenarios aected the diets of between
440 million and 2 billion people (Figure ES-4).
Highlights of the results are summarized below.
The agricultural land use and greenhouse gas emissions
associated with the average American diet were nearly
double those associated with the average world diet, with
80 to 90 percent of the impacts from consumption of
animal-based foods.
We found that producing the food for the average Ameri-
can diet in 2009 required nearly one hectare of agricul-
tural land, and emitted 1.4 tons of carbon dioxide equiva-
lent (CO2e), before accounting for emissions from land-use
change. These amounts of land use and greenhouse gas
emissions were nearly double those associated with the
average world diet that year (Figure ES-3). Animal-based
foods (shown in red, orange, and yellow in Figure ES-3)
accounted for nearly 85 percent of the production-related
greenhouse gas emissions and nearly 90 percent of agri-
cultural land use. Beef consumption alone (shown in red)
accounted for nearly half of the US diet-related agricul-
tural land use and greenhouse gas emissions.
Furthermore, factoring land-use implications into
agricultural greenhouse gas emissions estimates shows
a fuller picture of the consequences of people’s dietary
choices. For example, if an additional person eating the
average American diet were added to the world population
in 2009, the one-time emissions resulting from converting
a hectare of land to agriculture to feed that person would
be about 300 tons of CO2e. This amount is equal to 17
times the average US per person energy-related carbon
dioxide emissions in 2009. In other words, the emissions
from clearing additional land to feed an additional person
eating the US diet are equal to 17 years’ worth of an
average American’s energy-related CO2 emissions.
Shifting the diets of high consumers of animal-based
foods could significantly reduce per person agricultural
land use and greenhouse gas emissions.
When applied to the average American diet in 2009, the
Ambitious Animal Protein Reduction and Vegetarian Diet
scenarios reduced per person land use and agricultural
greenhouse gas emissions by around one-half—or down to
around world average. The three scenarios that reduced
consumption of beef—just one food type—reduced per
person land use and greenhouse gas emissions by 15 to
35 percent. Figure ES-3 shows the eects of the three diet
shifts on per person agricultural land use and greenhouse
gas emissions when applied to the average American diet.
8 |
DAILY FOOD
CONSUMPTION
(KCAL)
AGRICULTURAL
LAND USE
(HECTARES)
Beef Dairy Other Animal-Based Foods Plant-Based Foods
GHG EMISSIONS
FROM AGRICULTURAL
PRODUCTION
(TONS CO2E)
GHG EMISSIONS
FROM LAND-USE
CHANGE
(TONS CO2E)
0.96
0
0.3
0.6
0.9
1.2
1.5
0
5
10
15
20
1.4
15.2
0.90 0.93
US (ELIMINATE OBESITY
& HALVE OVERWEIGHT)
US (HALVE OBESITY
& OVERWEIGHT)
14.3 14.7
1.3 1.3
2,726
0.53 0.85
2,520 2,904
US (AMBITIOUS ANIMAL
PROTEIN REDUCTION)
US (TRADITIONAL
MEDITERRANEAN)
8.4
13.5
0.8
1.2
2,904
US (REFERENCE)
REDUCE OVERCONSUMPTION OF CALORIES REDUCE OVERCONSUMPTION OF PROTEIN BY
REDUCING CONSUMPTION OF ANIMAL-BASED FOODS
2,796
Figure ES-3 | Shifting the Diets of High Consumers of Animal-Based Foods Could Significantly
Reduce Per Person Agricultural Land Use and GHG Emissions
Source:
GlobAgri model.
Note:
All "US" data are for United States and Canada. Land-use change emissions are amortized over a period of 20 years and then shown as annual impacts. Calculations assume global average
efficiencies (calories produced per hectare or per ton of CO2e emitted) for all food types. “Other animal-based foods” includes pork, poultry, eggs, fish (aquatic animals), sheep, and goat.
WORKING PAPER | April 2016 | 9
Shifting Diets for a Sustainable Food Future
0
0.3
0.6
0.9
1.2
1.5
0
5
10
15
20
DAILY FOOD
CONSUMPTION
(KCAL)
AGRICULTURAL
LAND USE
(HECTARES)
Beef Dairy Other Animal-Based Foods Plant-Based Foods
GHG EMISSIONS
FROM AGRICULTURAL
PRODUCTION
(TONS CO2E)
GHG EMISSIONS
FROM LAND-USE
CHANGE
(TONS CO2E)
0.49
7.6
0.8
0.50
2,904
US (VEGETARIAN)
7.9
0.6
0.64 0.83 0.82
US (AMBITIOUS
BEEF REDUCTION)
US (SHIFT FROM BEEF
TO PORK AND POULTRY)
US (SHIFT FROM
BEEF TO LEGUMES)
10.2
13.0
13.2
0.9
1.1
1.2
2,834 2,904 2,904 2,433
WORLD (REFERENCE)
REDUCE CONSUMPTION OF BEEF SPECIFICALLY
REDUCE OVERCONSUMPTION OF PROTEIN BY
REDUCING CONSUMPTION OF ANIMAL-BASED FOODS
Figure ES-3 | Shifting the Diets of High Consumers of Animal-Based Foods Could Significantly
Reduce Per Person Agricultural Land Use and GHG Emissions (continued)
Source:
GlobAgri model.
Note:
All "US" data are for United States and Canada. Land-use change emissions are amortized over a period of 20 years and then shown as annual impacts. Calculations assume global average
efficiencies (calories produced per hectare or per ton of CO2e emitted) for all food types. “Other animal-based foods” includes pork, poultry, eggs, fish (aquatic animals), sheep, and goat. The
vegetarian diet scenario, which uses data from Scarborough et al. (2014), includes small amounts of meat, as “vegetarians” were self-reported.
10 |
Reducing animal-based food consumption results in
significant savings in global agricultural land use.
When applied globally to populations overconsuming
calories or protein, or who are high consumers of beef,
the diet scenarios could spare between 90 million and
640 million hectares of agricultural land. The Ambi-
tious Animal Protein Reduction scenario—which shifted
the diets of nearly 2 billion people in 2009—spared 640
million hectares of agricultural land, including more than
500 million hectares of pasture and 130 million hectares
of cropland. This area of land is roughly twice the size of
India, and is also larger than the entire area of agricul-
tural expansion that occurred globally over the past ve
decades. Notably, the Ambitious Beef Reduction scenario
spared roughly 300 million hectares of pasture—an
amount similar to the entire area of pasture converted
from other lands since 1961.
These results suggest that reducing consumption
of animal-based foods among the world’s wealthier
populations could enable the world to adequately feed
10 billion people by 2050 without further agricultural
expansion. Curbing agricultural expansion would also
avoid future greenhouse gas emissions from land-use
change. The Ambitious Animal Protein Reduction
scenario, which spared the most land, could avoid 168
billion tons of emissions of CO2e from land-use change.
To put this reduction in perspective, global greenhouse
gas emissions in 2009 were 44 billion tons CO2e. Figure
ES-4 shows the global eects of the three diet shifts on
agricultural land use in 2009.
All three diet shifts could contribute to a sustainable
food future, but the two shifts that reduce consumption
of animal-based foods result in the largest land use and
greenhouse gas reductions.
Our analysis of the three diet shifts, summarized in
Figures ES-3 and ES-4, yields the following insights:
1. REDUCE OVERCONSUMPTION OF CALORIES. While
reducing overweight and obesity is important for
human health, this diet shift contributed less to
reducing agriculture’s resource use and environmental
impacts than the other two shifts.
2. REDUCE OVERCONSUMPTION OF PROTEIN BY REDUCING
CONSUMPTION OF ANIMAL-BASED FOODS. This diet
shift resulted in the largest benets, as it applied
to a relatively large population and across all
animal-based foods.
3. REDUCE BEEF CONSUMPTION SPECIFICALLY. This diet
shift resulted in signicant benets, and would be
relatively easy to implement, since it only aects one
type of food. Additionally, some high-consuming
countries have already reduced per person beef
consumption from historical highs, suggesting that
further change is possible.
The diet shifts can also help close the gap between crop
calories available in 2006 and those demanded in 2050.
With a projected 25 percent of all crops (measured by
calories) dedicated to animal feed in 2050, we calculate
that the Ambitious Animal Protein Reduction scenario
could reduce the food gap by 30 percent—signicantly
reducing the challenge of sustain ably feeding nearly 10
billion people by mid-century.
Will the diet shifts adversely impact poor food
producers and consumers?
The diet shifts do not call for the world’s poor to reduce
consumption, and they preserve an abundant role for
small livestock farmers. The three shifts target popula-
tions who are currently overconsuming calories or protein,
or are high consumers of beef—or are projected to be by
2050. They do not target undernourished or malnourished
populations. Nor do they aim to eliminate the livestock
sector, which provides livelihoods to millions of poor
smallholders, makes productive use of the world’s native
grazing lands, and generates 40 percent of global agricul-
tural income. Indeed, solutions to sustainably increase
crop and livestock productivity are also critical to closing
the food gap, and are covered in the Interim Findings of
Creating a Sustainable Food Future.
Would reducing beef consumption result in
productive pastureland going to waste?
Reducing beef consumption is unlikely to result in
“wasted” pastureland for two reasons. First, beef demand
is projected to nearly double between 2006 and 2050, and
pasture is likely to remain the dominant source of feed.
Even with increased pasture productivity, it will be di-
cult to meet projected growth in demand without clearing
more natural forests and savannas for pasture. Our beef
WORKING PAPER | April 2016 | 11
Shifting Diets for a Sustainable Food Future
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reduction scenarios do not eliminate beef consumption,
but just reduce it. Given the projected growth in beef con-
sumption, the proposed diet shifts are unlikely to reduce
beef’s global land use below today’s levels. Accordingly,
“reducing beef consumption” is about preventing further
expansion, not creating a surplus of unused or “wasted”
pastureland. Second, because native grazing land has few
alternative uses, it is nearly always used for grazing. Even
if there were large enough reductions in beef consumption
to reduce total pasture area, the result would not be to stop
grazing of native pasturelands but instead to free up lands
that were naturally wooded and that are wet enough to meet
the growing demand for crops or for regenerating forests.
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Figure ES-4 | Reducing Animal-Based Food Consumption
Results in Significant Savings in Global Agricultural Land Use
millions of hectares saved relative to world reference, 2009
Shift from
Beef to
Legumes
Shift from
Beef to Pork
and Poultry
Ambitious
Beef Reduction
VegetarianTraditional
Mediterranean
Ambitious
Animal Protein
Reduction
Halve Obesity
& Overweight
Eliminate
Obesity & Halve
Overweight
0
100
200
300
400
500
600
700
Pasture
Cropland
Reduce overconsumption
of calories
Reduce overconsumption
of protein by reducing consumption
of animal-based foods
Reduce consumption
of beef specifically
1,385 1,046 1,907 437 437 1,463 1,952 1,952
Affected
Population
(millions)
Source:
GlobAgri model.
Note:
The
Shift from Beef to Pork and Poultry
scenario includes a 196 Mha decrease in pasture, but a 26 Mha increase in cropland, for an overall 170 Mha “savings.”
What can be done to shift people’s diets?
There is no silver bullet solution. To date, eorts to
encourage more sustainable eating have largely focused
on consumer education, back-of-the-package labeling,
and campaigns around abstinence (e.g., vegetarianism),
with limited success. A more holistic approach is needed
that works in step with how consumers make purchasing
decisions. Purchases are typically based on habit and
unconscious mental processing rather than on rational,
informed decisions. Furthermore, attributes like price,
taste, and quality tend to be more important than
sustainability in purchasing decisions. Strategies that
inuence these factors and engage actors in food value
12 |
chains (e.g., food manufacturing companies, food service
companies, supermarkets) are needed. The multinational
businesses that are increasingly inuencing consumers’
choices across the globe can play an important role in
shifting consumers to more sustainable diets.
To help shift people’s diets, we propose a new framework
based on proven private sector marketing tactics: the Shift
Wheel (Figure ES-5). The development of the Shift Wheel
was informed by a range of consumption shifts already
successfully orchestrated by industry, nongovernmental
organizations (NGOs), and government. These include
shifts such as from caged to free-range eggs in the United
Kingdom, from higher- to lower-alcohol beer in the United
Kingdom, and away from shark n in China.
The Shift Wheel comprises four complementary strategies:
▪MINIMIZE DISRUPTION. Changing food consumption
behavior typically involves changing ingrained habits.
This strategy seeks to minimize the disruption to
consumers’ habits caused by the shift. It can include
minimizing changes associated with the shift, such
as taste, look, texture, smell, packaging, and the
product’s location within a store.
▪SELL A COMPELLING BENEFIT. Selling a compelling
benet requires identifying and delivering product
attributes (such as health or aordability) that will be
suciently motivating to the consumer to stimulate a
behavior change. As plant-based proteins can be less
expensive than animal-based ones, companies may
have an opportunity to sell reformulated products
with a greater share of plant-based ingredients at a
lower price and/or an increased prot.
Figure ES-5 | The Shift Wheel Comprises Four Strategies to Shift Consumption
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SHIFT CONSUMPTION
Replicate the
experience
Disguise
the change
Form habits in
new markets
Meet current
key needs
Deliver new
compelling
benefit
Enhance
affordability
Enhance
display
Constrain
display
Be more
memorable
Make socially
unacceptable
Make socially
desirable
Inform about
the issue
Source:
Authors.
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WORKING PAPER | April 2016 | 13
Shifting Diets for a Sustainable Food Future
▪MAXIMIZE AWARENESS. The more consumers see or
think of a product, the greater the chance they will
consider purchasing it. Enhancing the availability and
display of the more sustainable food choice, and creat-
ing memorable advertising campaigns, can increase a
product’s visibility and the chance that consumers will
purchase it.
▪EVOLVE SOCIAL NORMS. What people eat is highly inu-
enced by cultural environment and social norms. In-
forming and educating consumers, along with eorts
to make the preferred food more socially desirable or
the food to be shifted from less socially desirable, can
inuence or change the underlying social and cultural
norms that underlie people’s purchasing decisions.
How can the Shift Wheel be applied to shift diets? The rst
step is to analyze the landscape of animal- and plant-based
food consumption in a given geography or market. Who
are the consumers? What are they eating? Where, when,
why, and how is this consumption occurring? The answers
to these questions will help identify the most promising
intervention points. This might be a specic occasion (e.g.,
family evening meals), a product format (e.g., meatballs),
a social perception (e.g., that plant-based protein is infe-
rior to meat), a demographic group (e.g., millennials), or
specic outlets (e.g., school or workplace cafeterias). The
next step is to design approaches to achieve the chosen
shift, drawing on relevant strategies from the Shift Wheel.
The nal steps are to test the selected approaches and
scale up successes.
What actions are needed to apply the
Shift Wheel and shift diets?
We oer four recommendations to help the food industry
apply the Shift Wheel and shift diets:
▪SET TARGETS, APPLY THE SHIFT WHEEL, LEARN FROM
THE RESULTS, AND SCALE UP SUCCESSES
Companies and governments should set quantiable
targets to reduce the consumption of animal-based
protein and beef specically. They should use the Shift
Wheel to drive progress toward these targets.
▪ENSURE GOVERNMENT POLICIES ARE ALIGNED WITH
PROMOTING SUSTAINABLE DIET CHOICES
Governments should ensure coherence among agri-
culture, health, water, and environmental policies in
relation to promoting sustainable diets.
▪INCREASE FUNDING FOR EFFORTS
TARGETED AT SHIFTING DIETS
Governments and foundations should create funding
mechanisms to support the development, testing, and
rollout of evidence-based strategies to shift diets.
▪CREATE A NEW INITIATIVE FOCUSED ON TESTING
AND SCALING UP STRATEGIES TO SHIFT DIETS
A new initiative should be established to apply the
Shift Wheel to specic contexts and catalyze new
approaches to shifting diets. Such an initiative could
conduct pilot tests, build an evidence base, measure
behavior change and its impacts on people and the
environment, and share and scale up successes. Its
goal should be to increase the share of plant-based
protein in diets and reduce the consumption of beef
specically.
14 |
The world faces a great balancing act. How will the world
adequately feed nearly 10 billion people by 2050 in a manner
that advances economic development and reduces pressure
on the environment, while adapting to climate change? This
requires balancing three needs. First, the world needs to close
a roughly 70 percent gap between the crop calories available
in 2006 and those needed by 2050 (the “food gap”). Second,
the world needs agriculture to contribute to inclusive economic
and social development. Third, the world needs to reduce
agriculture’s impact on the environment.
This edition of the World Resources Report,
Creating a
Sustainable Food Future
, proposes a menu of solutions that
can achieve this balance. The menu includes production-
focused solutions, such as sustainably increasing crop yields
and livestock pasture productivity, and consumption-focused
solutions, such as reducing food waste, achieving replacement-
level fertility, and reducing demand for bioenergy that makes
dedicated use of crops and land. This working paper focuses on
a consumption-focused solution: shifting people’s diets.
Since the 1980s, the World Resources Report has provided
decision makers from government, business, and civil society
with analyses and insights on major issues at the nexus of
development and the environment. For more information about
the World Resources Report and to access previous installments
and editions, visit www.worldresourcesreport.org.
Box 1 | The World Resources Report:
Creating a Sustainable Food Future
DIET MATTERS ON THE MENU
What we eat has a profound impact on our own health and
the planet’s health. In the World Resources Report’s Creat-
ing a Sustainable Food Future: Interim Findings (Box 1),
we describe how the world food system faces a great bal-
ancing act: feeding the population in 2050 while advancing
economic development and reducing agriculture’s pressure
on the environment in a changing climate. The Interim
Findings and an accompanying series of working papers
explores a menu of solutions that could combine to achieve
this balance.
Based on an adjusted FAO projection of food demand and
production by 2050, the world needs to close a roughly 70
percent gap between the crop calories available in 2006
and expected calorie demand in 2050 (Figure 1).1 Global
population is projected to grow to 9.7 billion by 2050.2
At least 3 billion more people are expected to enter the
global middle class by 2030,3 and two-thirds of the global
population is projected to live in cities by mid-century.4
A wealthier, more urban global population will likely
demand more food per capita—and more resource-inten-
sive foods such as meat and dairy.5 Without successful
measures to restrain the consumption of resource-inten-
sive foods by the world’s auent or to reduce waste, suf-
ciently feeding the world will require worldwide annual
crop production in 2050 to be more than 70 percent
higher than 2006 levels.6
While overall food demand—as measured by crop calo-
ries (Box 2)—is projected to rise by roughly 70 percent
between 2006 and 2050, demand for animal-based foods
is projected to rise even faster. Based on the latest, most
likely population projections, demand for meat and dairy
is projected to grow by nearly 80 percent. Demand for beef
specically—one of the most resource- and greenhouse-
gas-intensive foods—is projected to grow by 95 percent
between 2006 and 2050.7 Unless curbed, the demand for
animal-based products will make it hard to achieve several
of the United Nations Sustainable Development Goals,
including those on hunger, healthy lives, management of
water, consumption and production, climate change, and
terrestrial ecosystems.
Eorts to feed a growing and increasingly auent popula-
tion have primarily focused on increasing food production,
rather than addressing consumption. However, if the
world were to rely solely on increased production to close
the food gap, there would be enormous pressure to clear
the world’s remaining tropical forests and other natural
ecosystems to expand croplands and pasturelands. For
example, to avoid further expansion of harvested area,
the annual average increase in crop yields from 2006 to
2050 would need to be about one-third more than in the
previous 44-year period (1962 to 2006)—a period that
encompassed the Green Revolution.8 In addition, increases
in food production and the associated land-use changes
would make it even more dicult to limit global warming
to the internationally recognized goals of 1.5 to 2 degrees
Celsius above preindustrial levels.9 Agriculture and related
land-use change accounted for nearly one-quarter of
global greenhouse gas emissions in 2010. By 2050, they
could consume 70 percent of the total allowable global
emissions “budget” for limiting global warming to 2
degrees.10
WORKING PAPER | April 2016 | 15
Shifting Diets for a Sustainable Food Future
Figure 1 | A Menu of Solutions is Required to Sustainably Close the Food Gap
global annual crop production (kcal trillion)
2006
Available food
Increase
cropland
productivity
Increase
livestock &
aquaculture
productivity
Expand on to
low-environmental
opportunity-
cost lands
Avoid biofuel
competition for
crops & land
Achieve
replacement-
level fertility
Reduce food
loss & waste
Shift diets 2050
Baseline available
food needed
16,300
9,500
?
Increase production
Hold down consumption
ILLUSTRATIVE
Source:
WRI analysis based on Bruinsma (2009) and Alexandratos and Bruinsma (2012).
Note:
Includes all crops intended for direct human consumption, animal feed, industrial uses, seeds, and biofuels.
The world will need to do more than increase food produc-
tion and the eciency of production. Given the magnitude
of the challenge and the environmental impacts associated
with increased production, consumption-focused solutions
will also be necessary. One consumption-focused solution
is to shift diets—the type, combination, and quantity of
food consumed by people. There are good reasons to shift
diets aside from the need to close the food gap. One in
two people worldwide currently consumes a nutritionally
imbalanced diet as a result of overconsumption, hunger,
or micronutrient deciency.11 Shifting to more nutrition-
ally balanced diets could profoundly aect food security,
human health, healthcare costs, natural resource use, the
environmental impacts of agriculture, and animal welfare.
In this paper, we examine three interconnected diet shifts
that can contribute to a sustainable food future:
1. Reduce overconsumption of calories.
2. Reduce overconsumption of protein by reducing
consumption of animal-based foods.
3. Reduce consumption of beef specically.
This paper is primarily tailored to businesses that can play
a role in shifting diets. This includes actors in the food
value chain, particularly food service companies and food
retailers.
16 |
Box 2 | What Metric for Assessing Food
Security and Nutritional Requirements?
There is no one perfect metric for assessing global food security
or human nutritional requirements. FAO used economic value as
a metric in its 2009 estimate of a 70 percent food gap between
2006 and 2050.a Given that food prices fluctuate, economic
value does not provide a consistent unit of measure over time.
Another metric that has been used is food weight or volume (for
example, tons). Since this includes water, it does not provide a
reliable metric of the nutritional content of food.
This paper—and others in the
Creating a Sustainable Food
Future
series—measures the food gap between 2006 and 2050
in crop calories. Calories are consistent over time and avoid
embedded water. Measuring the calories embedded in crops
(production) rather than in foods (consumption) also has the
advantage of counting not only crops intended for human
consumption, but also animal feed, bioenergy, and other uses.
However—critically for this paper—this metric does not
capture the role of pastureland in supporting human food needs.
The analysis of the three diet shifts explored in this paper
focuses on total calories and one important macronutrient
(protein) because of their key role in nutritional health and the
availability of globally consistent data. Each of the modeled
diet scenarios in this paper was designed to ensure adequate
amounts of calories and protein to the populations affected
by the scenarios. Two of the scenarios—vegetarian and
Mediterranean-style diets—were based on realistic diets that
are high in nutrient-rich foods.
It should be noted, however, that other nutrients are needed
for a balanced diet. A narrow focus on calories and protein
could lead to nutritionally unbalanced diets. For example, an
“environmentally sustainable diet” that sought only to maximize
calories produced per hectare could inadvertently encourage
production of high-yielding, energy-dense crops, such as
sugars and cereals, in place of lower-yielding, but nutrient-
rich crops, such as fruits, vegetables, and beans. As a result,
“shifting diets” should be implemented with an eye to providing
not only adequate amounts of calories and protein, but also all
other nutrients essential to human health. This is particularly
important given that micronutrient deficiencies—or “hidden
hunger”—affected more than 2 billion people in 2010–12, with
the most common deficiencies including iodine, iron, zinc, and
vitamin A.b
Notes:
a. Bruinsma (2009).
b. FAO, WFP, and IFAD (2012).
We do not suggest that everyone should become a vegan
or vegetarian. Nor do we aim to reduce food consumption
among undernourished or malnourished populations.
We do not seek to eliminate the livestock sector, which
provides livelihoods to millions of poor smallholders
and generates 40 percent of global agricultural income.12
Rather, we focus on reducing overconsumption of calories
and protein, decreasing the share of animal-based protein
in diets, and reducing the consumption of beef specically.
For each of the three proposed diet shifts, we dene the
issues, explain why they matter, and review projected con-
sumption trends. We then quantify the projected eects
of the shifts on the land use and greenhouse gas impacts
of agriculture in 2009, using the version of the GlobAgri
model developed for Creating a Sustainable Food Future
(Box 3). The greenhouse gas emissions estimates include
both emissions from agricultural production and emis-
sions from land-use change. Regarding land-use change
emissions, we estimate the emissions that would occur
from conversion of forests, savannas, and other lands
to produce the additional foods13 based on existing crop
yields, livestock eciencies, and patterns of trade (Box
4). We then assess the eects of the diet shifts in 2050,
including their potential to help close the food gap.
Next, we outline a novel approach to address the cru-
cial question of how to shift people’s diets. We consider
strategies beyond information and education campaigns,
and draw on practices employed by the consumer goods
industry that have successfully changed consumption
patterns. We conclude with four recommendations for
shifting diets.
In our assessment, the three proposed diet shifts meet
the development and environmental criteria introduced
in the World Resources Report’s Interim Findings
(Table 1). They reduce the pressure of agriculture on
ecosystems, climate, and water, and oer potential
benets for human health.
WORKING PAPER | April 2016 | 17
Shifting Diets for a Sustainable Food Future
Box 3 | An Overview of the GlobAgri-WRR Model
This paper uses the GlobAgri-WRR model
(“GlobAgri”), which is a version of the
GlobAgri model developed by the Centre
de Coopération Internationale en Recherche
Agronomique pour le Développement
(CIRAD), Princeton University, the Institut
National de la Recherche Agronomique
(INRA), and WRI. GlobAgri is a global
biophysical model that quantifies the
greenhouse gas emissions and land-use
effects of agricultural production. It estimates
emissions from agricultural production,
primarily methane and nitrous oxide, and
carbon dioxide from the energy used to
produce fertilizers and pesticides or to run
farm machinery. It also estimates emissions
from land-use change (Box 4). It does not
include emissions from food processing,
transportation, retail, or cooking.
GlobAgri links food consumption decisions
in each country or region (see Appendix
A for list of countries and regions) to the
production of the crops, meat, milk, or
fish necessary to meet food demands after
accounting for food loss and waste at each
stage of the value chain from farm to fork.
Its core data for production, consumption,
and yields are based on data from FAO
(2015). The model accounts for the multiple
food, feed, and energy products that can
be generated by each crop, and reflects the
estimates of crop calorie content by region
as estimated in FAO (2015). It estimates
land use and greenhouse gas emissions
related to agricultural production in each of
the world’s countries in light of crop yields,
population, diets, production methods,
and levels of food loss and waste—factors
that can all be modified to examine future
scenarios of agricultural production and
food consumption.
To analyze the eight alternative diet scenarios
explored in this paper, GlobAgri held all
other consumption and production factors
constant. For example, the model assumes
additional food would be supplied at the
same average crop yields, using the same
average livestock production measures,
and with the same rates of food loss and
waste as in the 2009 reference scenario.
The model similarly assumes that the role
of imports and expor ts would remain the
same; for example, if 20 percent of a crop
in Country A is imported from Country B,
that percentage would remain true under
scenarios of altered demand for that crop.
The GlobAgri model differs from some
other global agriculture and land-use
models in that it does not incorporate
economic feedback effects. For example,
if people in one country were to increase
food consumption, the prices of those
foods would increase, potentially
triggering changes in food production and
consumption in other countries. Economic
models can be used to simulate these
feedback effects, but given the uncertainties
associated with these interactions, they
need to make a number of assumptions,
making the results highly variable.
Furthermore, it seems inappropriate—when
evaluating the consequences of a resource-
intensive diet (for example, one high in
animal-based foods)—to “credit” that diet
for reduced food consumption by others.
Patrice Dumas (CIRAD) is the principal
architect of the GlobAgri-WRR model,
working in partnership with Tim
Searchinger of Princeton University and
WRI. Other researchers contributing to the
core model include Stéphane Manceron
(INRA) and Richard Waite (WRI).
A major strength of the GlobAgri model
is that it incorporates other biophysical
submodels that estimate emissions or
land-use demands in specific agricultural
sectors. GlobAgri therefore benefits from
other researchers’ work, incorporating
the highest levels of detail available.
Major subcomponents include a livestock
model with lead developers Mario Herrero
(CSIRO) and Petr Havlik (IIASA), with
extra contributions from Stefan Wirsenius
(Chalmers University); a land-use model
with lead developer Fabien Ramos of the
European Commission Joint Research
Centre; a global rice model with lead
developer Xiaoyuan Yan of the Chinese
Institute for Soil Science; a nitrogen
emissions model with lead developer Xin
Zhang of Princeton University; and an
aquaculture model with lead developer
Mike Phillips of WorldFish and Rattanawan
Mungkung of Kasetsart University. Each of
these submodels had several contributors.
Information on vegetarian diets was
based on information provided by Peter
Scarborough and Paul Appleby of the
University of Oxford.
18 |
Box 4 | How Does the GlobAgri Model Quantify the Land-Use-Related
Greenhouse Gas Effects of Different Food Choices?
The GlobAgri model estimates the amount
of agricultural land needed to produce
a specific quantity of food required by a
given diet assuming present crop yields,
production systems, and trade. It assumes
that any agricultural expansion triggered by
a change in diet will come at the expense
of forests, savanna, or some other native
vegetation. The resulting loss of carbon
in plants and soils provides the quantity
of greenhouse gas emissions from land
use attributed to the diet. Conversely,
under scenarios of reduced food demand,
GlobAgri estimates negative land-use-
change emissions (or avoided future
emissions), simulating the restoration of
agricultural land to native vegetation. The
model does not consider how economic
feedbacks might alter other demands,
production systems, or yields.
How have other studies quantified the
greenhouse gas effects of changes in
agricultural land use?
Informed by Schmidinger and Stehfest
(2012), we identified three broad
approaches that life-cycle assessments of
agriculture and/or alternative diets generally
use to quantify the greenhouse gas effects
associated with changes in land use:
1. Land-use-change emissions are
not estimated. Most conventional
life-cycle assessments of agriculture
account for the land area required to
produce the foods being studied, but
do not assign any land-use-change-
related greenhouse gas emissions to
that land. Estimates of greenhouse
gas emissions in such studies are
limited to sources from agricultural
production (not land-use change),
such as methane from livestock and
energy used to run farm machinery.
2. Land-use-change emissions are
averaged over total agricultural
production and land use in the
study period. Under this approach,
land-use-change emissions per unit
of food produced are generally quite
low—and can even be zero if land-use
change did not occur during the study
time frame. Some of these studies
do this calculation just for a specific
crop and in a specific country. For
example, if soybean area is expanding
in Brazil, but not in the United States,
the emissions from this expanding
soybean area are allocated to all the
production of soybeans in Brazil,
but none are assigned to soybean
production in the United States. This
approach would assign land-use-
change emissions to a European
pork producer who imports soybeans
from Brazil, but not one who imports
soybeans from the United States.
3. Land-use-change emissions
are attributed to marginal
(additional) agricultural
production. This approach—
employed by GlobAgri and most
biofuel studies—focuses on the
additional emissions from the
additional land required to produce
any additional amount of a crop or
other food. Under this approach, land-
use-change emissions per unit of food
produced are much higher than in
approach (2), and are never zero.
A hypothetical example illustrates the
difference between approach (2) and
approach (3). Assume that in 2009,
soybeans occupied 5 million hectares of
land in a country and produced 2 tons
per hectare, for a total production of 10
million tons. Each ton of soybeans therefore
required half a hectare of cropland.
Now assume that in 2010, soybean area
expanded by 100,000 hectares to 5.1
million hectares, while yields stayed
constant, meaning that production grew by
200,000 tons (from 10 million tons to 10.2
million tons). Suppose that these additional
100,000 hectares came from clearing forest
that contained 400 tons of CO2e per hectare.
In approach (2), the 100,000 hectares
of land-use change and the resulting
emissions of 40 million tons of CO2e would
be assigned to all 10.2 million tons of
soybeans, resulting in a small quantity of
emissions per ton (around 4 tons of CO2e
per ton of soybeans produced).
In fact, if we change this example and
assume that soybean yields grew just
enough in 2010 to produce 10.2 million
tons of soybeans on the same 5 million
hectares of land (in other words, with
no expansion of the soybean area),
this approach would attribute no land-
use change (and no land-use-change
emissions) to soybeans. Under approach
(2), eating meat fed entirely by soybeans
from this country has no land-use
emissions cost.
What approach (2) does not tell us is how
much extra land use was required for each
additional ton of soybeans in 2010. In the
first example above, if soybean demand
had not gone up by 200,000 tons in 2010,
soybean area would not have expanded at
all. The increase of 200,000 tons required
the extra 100,000 hectares. Approach (3)
therefore assigns the land-use-change
emissions from converting those 100,000
hectares only to the 200,000 additional
tons of soybeans. In this example,
therefore, each additional ton of soybeans
is responsible for emitting 200 tons of
CO2e. Recognizing that land converted into
agricultural production can sustain crops
or livestock over many years, we follow
the approach taken by the European Union
for estimating land-use-change emissions
for biofuels, and amortize the land-use-
change emissions over 20 years. In our
example, this amortization therefore assigns
emissions of 10 tons of CO2e per year per
WORKING PAPER | April 2016 | 19
Shifting Diets for a Sustainable Food Future
Box 4 | How Does the GlobAgri Model Quantify the Land-Use-Related
Greenhouse Gas Effects of Different Food Choices? (continued)
additional ton of soybeans produced.
GlobAgri applies this “marginal” approach
(3) in this paper in order to gain a fuller
picture of the land and greenhouse gas
consequences of diet shifts, which by
definition happen at the margin. For any
given yield, each additional ton of food
demanded requires a certain amount of
additional land, which results in a certain
amount of land-use-change emissions. The
converse is also true—each ton of food no
longer demanded (e.g., under scenarios
that reduced consumption of animal-based
foods and as a result reduced demand for
crop-based feed) results in a decrease
in agricultural land use and negative
land-use-change emissions if agricultural
land reverts to native vegetation. However,
because global agricultural land is
expanding—as food demand growth
continues to outpace yield growth—the
real-world consequences of reducing food
demand under the scenarios modeled in
this paper would be to avoid future land-use
change. This avoided land-use change and
associated greenhouse gas emissions are
what GlobAgri estimates.
This approach reveals that each person’s
diet matters quite a lot for agricultural land
use and the associated greenhouse gas
emissions. Regardless of what anyone
else does, individual dietary choices
affect demand for land “at the margin”
and therefore have a significant effect on
greenhouse gas emissions.
Why does GlobAgri not consider the
economic effects of changes in food
supply and demand?
The GlobAgri model is designed to answer
the question of how much agricultural
land would be required for a given level
of food demand, crop yield, and livestock
production efficiency. It does not assess
whether and by how much an increase or
decrease in food demand by one group
of people leads to price changes and
economic feedbacks that in turn shift other
people’s demands, farmers’ yields, and/or
production techniques. Such economic
effects are highly complex and uncertain.
As a result, there is limited underlying
economic evidence that can be used
to robustly estimate them.a In addition,
economic assessments do not fully
capture the land-use “opportunity costs”
of diet choices. Consider, for example,
a scenario in which a relatively wealthy
person increases their beef consumption.
This change in demand would likely lead
to an increase in beef and grain prices and
could cause a poorer person elsewhere
to consume less grain or beef as prices
increase. This “crowding out” of the poorer
person’s food demand does reduce global
land-use demands relative to a world in
which the poorer person’s grain demand is
unaffected by the wealthier person’s beef
demand. However, it seems inappropriate,
when evaluating the consequences of a
resource-intensive diet, to “credit” that
diet for reduced food consumption by
others, even if this does lead to potential
overestimates of the greenhouse gas
benefits of reducing consumption. By
eliminating the economic feedback effects
from the analysis, GlobAgri can more
transparently estimate what combinations of
diet shifts, yield gains, and other solutions
would be necessary to achieve a sustainable
food future.
Even without considering the economic
interactions of changes in food supply
and demand, there are still many other
uncertainties in estimating both the type of
lands that are likely to be converted and the
quantity of carbon that conversion would
release. All model estimates, including
those of GlobAgri, should therefore be
considered rough.
Note:
a. Searchinger et al. (2015) and supplement; Berry (2011).
20 |
Table 1 | How “Shifting Diets” Performs Against the
Sustainable Food Future
Criteria
= positive = neutral/it depends
CRITERIA DEFINITION PERFORMANCE COMMENT
Poverty
alleviation
Reduces poverty and advances
rural development, while still
being cost effective
Careful policy choices would be needed to ensure that the diet
shifts make food affordable to all, and do not adversely impact poor
livestock farmers.a
Gender Generates benefits for women The diet shifts would provide health benefits for women.
Ecosystems
Reduces pressure for
agricultural expansion and
intensification on existing
agriculture land
The diet shifts would reduce the land needed for food production.
Reducing consumption of animal-based food products, particularly
beef and dairy, would lower the pressure to convert forests and wooded
savannas into pasturelands.
Climate
Reduces greenhouse gas
emissions from agriculture
to levels consistent with
stabilizing the climate
The diet shifts would contribute to stabilizing the climate.b Shifting diets
would reduce the need to convert forests to crop and pastureland, apply
more fertilizers, and raise more livestock. Reducing overconsumption
of calories would reduce the need for energy for producing, processing,
transporting, and storing food.
Reducing beef consumption specifically would reduce methane emissions
from enteric fermentation and manure and nitrous oxide (N2O) from excreted
nitrogen and the chemical nitrogenous fertilizers used to produce feed for
animals kept in feedlots.
Water Reduces water consumption
and pollution
The diet shifts would reduce the quantity of water needed for food
production. They would also reduce the contribution of agriculture
to water pollution.
Notes
:
a. USDA/HHS (2015).
b. Hedenus et al. (2014).
WORKING PAPER | April 2016 | 21
Shifting Diets for a Sustainable Food Future
CONVERGING DIETS
Around the world, eating habits are converging toward
Western-style diets high in rened carbohydrates, added
sugars, fats, and animal-based foods. Consumption of
pulses,14 other vegetables, coarse grains, and ber is
declining.15 Three interconnected global trends are asso-
ciated with this convergence. First, rising incomes are
associated with rising demand for animal-based foods,
vegetable oils, and added sugars.16 Second, increasing
urbanization (also associated with rising incomes) pro-
vides easy access to supermarkets, restaurants, fast food
chains, and foods that they supply, including meat, dairy, and
processed foods and drinks.17 Third, technological advances,
business and economic changes, and government policies are
transforming entire food chains, from farm to fork. Multi-
national agribusinesses, food manufacturers, retailers,
and food service companies increasingly inuence what is
grown and what people eat, a trend that is spreading from
high-income to low- and middle-income countries.18
These trends—combined with more sedentary lifestyles—
aect nutritional and health outcomes, including height,
weight, and the prevalence of noncommunicable dis-
eases.19 Diet-related noncommunicable diseases include
hypertension, type 2 diabetes, cardiovascular diseases,
and certain types of cancer.20
FAO food supply data—adjusted downward from “per
capita food availability” to “per capita food consumption”21
to account for food loss and waste during the consump-
tion stage of the food supply chain—indicate that the
consumption of calories and protein is already above average
requirements in the majority of developed countries. Per
capita food consumption also is rapidly rising in emerging
economies, including China and Brazil.22 In this paper, we
build on FAO’s projections23 to estimate food consumption
levels in 2050. We nd that in 2050, emerging economies
will likely exhibit per capita consumption levels—in terms
of calories, protein, and consumption of animal-based
foods—comparable to today’s developed countries.24
Why does this global convergence in diets matter? Foods
dier vastly in terms of the quantity of land, water, and
energy needed per unit of energy and protein ultimately
consumed, and in terms of their greenhouse gas impacts
(Figure 2).25 Although the data in Figure 2 are global
means for current agricultural production26—masking
variations among locations, production systems, and
farm management practices (Box 5)—they enable general
comparisons across food types.
Unlike many other studies (Box 4), the comparison of food
types in Figure 2 incorporates both land used for pasture
and greenhouse gas emissions associated with changes in
land use. Key ndings from this more inclusive approach,
using the GlobAgri model, include:
▪Animal-based foods are generally more resource-
intensive and environmentally impactful to produce
than plant-based foods.
▪Beef and other ruminant meats (sheep and goat) are
by far the most resource-intensive of foods, requiring
four to six times more land and generating that many
times more greenhouse gas emissions than dairy per
calorie or unit of protein ultimately consumed by
people. Beef and other ruminants also require more
than 20 times more land and generate more than 20
times more greenhouse gas emissions than pulses per
unit of protein consumed.
▪Dairy’s land use and greenhouse gas emissions are
slightly higher than those of poultry per calorie con-
sumed and signicantly higher than those of poultry
per unit of protein consumed.
▪Poultry and pork have similar greenhouse gas emis-
sions and land use per unit of protein consumed,
but poultry’s land use and emissions are higher than
pork’s per calorie consumed mainly because of the
high energy content of pork fat.
▪Pulses, fruits, vegetables, and vegetable oils are gener-
ally more resource-intensive to produce than sugars
and staple crops, but still compare very favorably to
animal-based foods.
▪Factoring land-use implications into agricultural
greenhouse gas emissions estimates shows a fuller
picture of the consequences of people’s dietary choices.
For all food types, the annualized emissions from land-
use change (shown in orange in Figure 2) are far higher
than emissions associated with agricultural production
(shown in light orange). For example, when considering
production emissions only, consumption of a million
calories of beef would generate 19 tons of CO2e, while
the same quantity of pulses would generate 0.4 tons of
CO2e, a savings of 18.6 tons of CO2e. But when factoring
in land use, emissions would fall from 201 tons of CO2e
(for beef) to 7 tons of CO2e (for pulses), a savings of 194
tons of CO2e or more than 10 times the amount when
considering only production-related emissions.
22 |
Figure 2 | Foods Differ Vastly in Resource Use and Environmental Impacts
Sources:
GlobAgri model (land use and greenhouse gas emissions), authors’ calculations from Mekonnen and Hoekstra (2011, 2012) (freshwater consumption), and Waite et al. (2014)
(farmed fish freshwater consumption).
Notes:
Data presented are global means. Entries are ordered left to right by amount of total land use. Indicators for animal-based foods include resource use to produce feed, including pasture.
Tons of harvested products were conver ted to quantities of calories and protein using the global average edible calorie and protein contents of food types as reported in FAO (2015). “Fish”
includes all aquatic animal products. Freshwater use for farmed fish products is shown as rainwater and irrigation combined. Land use and greenhouse gas emissions estimates are based on
a marginal analysis (i.e., additional agricultural land use and emissions per additional million calories or ton of protein consumed). Based on the approach taken by the European Union for
estimating emissions from land-use change for biofuels, land-use change impacts are amortized over a period of 20 years and then shown as annual impacts. Land use and greenhouse gas
emissions estimates for beef production are based on dedicated beef production, not beef that is a coproduct of dairy. Dairy figures are lower in GlobAgri than some other models because
GlobAgri assumes that beef produced by dairy systems displaces beef produced by dedicated beef-production systems.
0
30
60
90
120
150
180
PROTEIN CONSUMED CALORIE CONSUMED
Pulses Fish
(farmed)
EggsPork Poultry Dairy Beef
LAND USE (ha)
Pasture
Cropland
GHG EMISSIONS (t CO2e)
Land-use change
Agricultural production
FRESHWATER CONSUMPTION (1,000 m3)
Rainwater
Irrigation
ANIMAL-BASEDPLANT-BASED
PER TON PROTEIN CONSUMED PER MILLION KILOCALORIES CONSUMED
Wheat Soybean Oil Fruits &
Vegetables
Sunflower
Seed Oil
Rice Rapeseed
& Mustard
Seed Oil
Sugar Maize PulsesRoots &
Tubers
Fish
(farmed)
EggsPork Poultry Dairy Beef
LAND USE (ha)
Pasture
Cropland
GHG EMISSIONS (t CO2e)
Land-use change
Agricultural production
FRESHWATER CONSUMPTION (1,000 m3)
Rainwater
Irrigation
ANIMAL-BASEDPLANT-BASED
Rice Maize Roots &
Tubers
Wheat
0
3
6
9
12
15
ha
120 3,000
1,000 m3 t CO2e
100 2,500
80 2,000
60 1,500
40 1,000
20 500
ha 1,000 m3 t CO2e
10 250
8200
6150
4100
250
WORKING PAPER | April 2016 | 23
Shifting Diets for a Sustainable Food Future
Figure 2 | Foods Differ Vastly in Resource Use and Environmental Impacts (continued)
Sources:
GlobAgri model (land use and greenhouse