United States Department of Agriculture

Resource Requirements of Food Demand 

in the United States

Patrick Canning, Sarah Rehkamp, Claudia Hitaj, 

and Christian Peters

Economic

Research

Service

Economic

Research

Report

Number 273

May 2020
Economic Research Service 

www.ers.usda.gov

United States Department of Agriculture

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Recommended citation format for this publication:

Canning Patrick, Sarah Rehkamp, Claudia Hitaj,and Christian Peters. Resource 

Requirements of Food Demand in the United States, ERR-273, May 2020. 
United States Department of Agriculture

Economic

Research

Service

Economic

Research

Report

Number 273

May 2020

Resource Requirements of Food Demand in 

the United States

Patrick Canning, Sarah Rehkamp, Claudia Hitaj, 

and Christian Peters

Abstract 

Natural resources facilitate production of an adequate daily food supply for Americans. Food 

consumption in the United States, measured in total calories per day, increased about 50 

percent over a recent 25-year span. Understanding how changes in food consumption impact 

the U.S. food system’s use of the country’s natural resources requires consideration of many 

factors. We find that diets, or food choices, are likely to be an important factor. For example, 

had the diets of Americans who met all the 2010 USDA Dietary Guidelines for Americans 

back in 2007 become the typical American diet of that time, then per capita consumption of 

the fruits, vegetables, legumes/nuts/seeds, eggs, and dairy categories would have increased, 

while per capita consumption in the sugars/sweets/beverages, fats/oils/salad dressings, 

grain products, and meat/poultry/fish/mixtures food groups would have declined. In such a 

scenario, under the production and marketing practices in 2007, nutrition and resource conservation goals would have been mostly complementary, or synergistic. As one notable exception, 

water conservation in particular may have required tradeoffs between competing goals, especially for production of fruits, vegetables, and dairy. This report combines empirical evidence 

of resource use in the system in 2007 with the presentation of a framework for a broader 

empirical study of sustainable pathways to producing a healthy and adequate food supply. 

Keywords: diets, Dietary Guidelines for Americans, natural resources, sustainability, U.S. 

food system

Acknowledgments

The authors thank the following individuals for their reviews and comments: Marcel 

Aillery, Kelly Maguire, Constance Newman, Timothy Park, and Katherine Ralston, U.S. 

Department of Agriculture (USDA), Economic Research Service (ERS); Jared Creason, U.S. 

Environmental Protection Agency; Stephan Goetz, Pennsylvania State University; and Parke 

Wilde, Tufts University. Thanks also to Courtney Knauth and Andrea Pimm of USDA-ERS 

for editorial and design services. 

This research was supported in part by the intramural research program of the U.S. 

Department of Agriculture, Economic Research Service. Christian Peters’ contributions were 

supported, in part, by a cooperative agreement with ERS (Cooperative Agreement number 

58-4000-5-0004).
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Contents

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Conceptual Framework . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

How Do We Determine American Diets? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

How Do We Identify and Measure Resources in the 

U.S. Food System? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Which Resource Materials and Services Are Important to Food Production? . . . . . . . . . . . . . . 7

How Is Resource Use Measured in the U.S. Food System? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Results of Food Demand Scenarios . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Total Resource Requirements of the Baseline Diet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Resource-Use Comparisons at Different Supply Chain Stages . . . . . . . . . . . . . . . . . . . . . . . . . 14

Evidence of Synergies and Tradeoffs in Food Demand Scenarios . . . . . . . . . . . . . . . . . . . . . . 15

Future Directions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Technical Appendix: Methods for Measuring Diets, Production, and Resources . . . . . . . . . 25

Modeling Healthy Diets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Measuring Diet-Related Fossil Fuel Combustion and Water Withdrawals . . . . . . . . . . . . . . . . 25

Measuring Land Use and Farm Animal Inventories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Measuring Air Use as a Repository for GHG Emissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Measuring Forest Product Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Errata

On September 15, 2020, Resource Requirements of Food Demand in the United States was 

revised to correctly identify the units for greenhouse gasses as metric tons throughout the report . 
ERS is a primary source 

of economic research and 

analysis from the U.S. 

Department of Agriculture, 

providing timely information on economic and policy 

issues related to agriculture, 

food, the environment, and 

rural America. www.ers.usda.gov

United States Department of Agriculture

Resource Requirements of Food Demand 

in the United States

Patrick Canning, Sarah Rehkamp, Claudia Hitaj, 

and Christian Peters

Economic 

Research 

Service

Economic 

Research 

Report 

Number XXX

April 2020

United States Department of Agriculture

A report summary from the Economic Research Service May 2020

Resource Requirements of Food Demand in the 

United States

Patrick Canning, Sarah Rehkamp, Claudia Hitaj, and Christian Peters

Summary

What Is the Issue?

The U.S. food system comprises all businesses that are either directly or indirectly involved 

in producing and marketing food products, such as the producers of farm inputs like fertilizers and machinery, the farmers growing food and feed commodities, and the processors 

making food products, plus the food merchants and eating places where U.S. consumers 

spent over $1.8 trillion on food and beverages in 2018. Natural resources—land, water, 

minerals, air, and forests—provide materials and services necessary to produce and market 

the food we eat. To supply the food production to meet the food demand of a growing 

population, it is important to understand the U.S. food system’s impact on these natural 

resources. This report concerns only the food system’s production and marketing of food 

products for purchase by or for all American food consumers.

Three main factors determine the resource requirements of food demand: Population (how 

many consumers?), diet (what will they consume?), and technology (how will our food 

system produce, market, and preserve our food supply?). This study focused on the use of 

natural resources in the U.S. food system by examining recent research on one of these 

factors, diet, to illustrate how food choices can affect use of resources.

What Did the Study Find?

We estimated use of natural resources in the food system for a set of age and genderspecific Baseline diets, based on food consumption in 2007, and compared results to those 

for a set of Healthy American diets based on the 2010 Dietary Guidelines for Americans. 

The study produced the following insights:

1 . The 2007 Baseline diets were resource-intensive . Since total annual expenditures 

on food in the United States were 8.6 percent of U.S. gross domestic product (GDP) 

in 2007, we considered use of a natural resource by the food system to be an intensive 

use if greater than 8.6 percent of the resource's 2007 domestic use was dedicated to 

food. To accommodate all Baseline diets, model results indicate the U.S. food system 

used 25.5 percent of the country’s total land area, including over half (53 percent) of 

productive agricultural land. It used 28 percent of total freshwater withdrawals, 11.5 

percent of total fossil fuel consumption, 18.1 percent of total greenhouse gas (GHG) 

emissions, and 7.2 percent of total marketed forest products. With the exception of 

forest products, each of these was intensive use of the resource by the food system. 

2 . Substantial resource requirements occur beyond the farmgate. The stages of 

the food system most reliant on natural resources differ substantially across the five 

resources considered. Land use and freshwater withdrawals were both resourceintensive on-farm in 2007. Conversely, agriculture accounts for less than half of 

total resource use for the Baseline diet of fossil fuels, air (as a GHG repository) and 

forestry products; the majority of these resource requirements are in supply-chain 

stages further downstream.
www.ers.usda.gov

3. The modeled Healthy American diet would lead to significant changes in food consumption

compared to Baseline diets. The Healthy American diet is based on the diets of Americans who

met all 2010 USDA Dietary Guidelines for Americans in 2007, as determined by an analysis of a

nationally representative survey designed to assess the health and nutritional status of Americans.

Consumption in the fruits, vegetables, legumes/nuts/seeds, eggs, and dairy categories would increase,

while consumption in the sugars/sweets/beverages, fats/oils/salad dressings, grain products, and meat/

poultry/fish/mixtures food groups would decline. The composition of food items within each food

group would change, as well as the categories’ total calories.

4. A shift to the modeled Healthy American diet in 2007 would have decreased use of some

resources but increased the use of others. This scenario assumes a shift that aligned all Americans,

on average, with the Healthy American diet, and that the food system had not changed its production

methods. Use of productive agricultural land, fossil fuels, and forest products would have decreased,

while freshwater withdrawals increased. Use of air as a repository for diet-related greenhouse gas emissions (GHG) would have remained essentially unchanged with a conversion to the Healthy American

diet. Reductions in GHG emissions linked to reduced fossil fuel use would have been offset by

increases linked to biogenic emissions.

This study also presents a framework for a broader empirical analysis of sustainable pathways to producing a 

healthy and adequate food supply that accounts for population and technology change. The authors found that 

several ERS models provide useful frameworks along these lines.

How Was the Study Conducted?

Given the high level of uncertainty about eating patterns and technologies looking ahead, we developed a range 

of scenarios with an array of model frameworks to study potential outcomes. At the time of the recent ERS 

analysis that this report builds on, the 2007 National Benchmark Make and Use Tables for the production 

model of our analysis, published in 2015, provided the latest data of sufficient detail for this purpose, so our 

analysis is based on the 2007 U.S. food system. We use a mathematical optimization model to define diets using 

the attributes of individual food items consumed by Americans in 2007. We use an environmentally extended 

economic model, FEDS-EIO, to account for the use of natural resources throughout the entire food value chain 

from farm inputs through home kitchen operations. We use a biophysical model, Foodprint, to estimate land and 

animal inventory requirements of producing all food commodities embodied in the model-derived diets. Model 

results from this research do not include any international resource use embodied in imported food and ingredients and do not account for any U.S. resource use for the production of food exported to other countries. 

Estimated diet-related share of total resource use across five categories, 2007

Diet related Diet related Non-diet related

25.5%

28.0%

11.5%

18.1%

7.2% 8.6% 0.0

100.0

8.6

Percent

Total land

area (acres)

Freshwater

withdrawals

(gallons per day)

Fossil fuel

energy use

(Btu)

Greenhouse

gas emissions

(metric tons CO2eq)

Non-diet related

Forest 

product

use ($)

Diet

contribution

to GDP ($)

2.3 billion

acres

349 billion

gallons/day

85.9

quadrillion Btu

7.4 billion

metric tons

22.4

billion $

14.4

trillion $

Notes: Btu = British thermal units. GDP = gross domestic product. 

Source: USDA, Economic Research Service.
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Introduction

The U.S. food system comprises all businesses that are either directly or indirectly involved in 

producing and marketing food products. Examples of businesses with direct involvement are the 

farmers growing the crops and animal food products, the mills and animal-processing plants that 

transform food grains, oil seeds, and meat animals into processed food ingredients and food commodities, and the supermarkets and restaurants that serve as points of purchase for U.S. food consumers, 

who spent over $1.8 trillion in 2018 on food and beverages (USDA, ERS, 2020). Examples of businesses with indirect involvement are the electric utility and paper mill companies that produce electric 

power and paper products for all businesses and households in their service area, including businesses 

running oilseed milling machinery and selling food products in paper packaging, and households 

running kitchen appliances and using napkins and paper towels for serving and cleaning up after 

meals. Additionally, the commercial cold storage facilities and in-home refrigerators and freezers 

used for food storage, and the transport of food and food ingredients (such as between businesses at 

different stages of the supply chain and personal travel to grocery stores) are part of our food system. 

Natural resources are essential to the production of food for human consumption. From the farmland 

and freshwater that facilitate crop and animal product production, to the mineral and forest products 

used to make building materials and as sources for energy to power industry and preserve foods, to the 

air used to both extract nitrogen for fertilizers and as a repository for various byproducts of production 

and consumption, natural resources have a central role throughout our food system. 

This report, which examines resource use throughout the U.S. food system, is concerned 

only with the food system’s production and marketing of food products for purchase by or 

for all American food consumers. To study resource use implications of changes to U.S. food 

consumption, like the roughly 50-percent increase1 in U.S. caloric consumption between 

1985 and 2010, we begin with a conceptual framework for the measurement of food-related 

uses of natural resources. Our approach involves the use of extensive primary data sources 

covering food consumption, food production, and the use of natural resources. These data are 

used to compile models that produce estimates that link both observed and model-derived diet 

outcomes to estimates of how much natural resources are used to accommodate these diets.

The report then provides detailed descriptions of our approaches and data sources for measuring and 

modeling observed and alternative American diets and identifying and estimating resources used to 

produce the food that accommodates these diets. Next, results of the analysis are reported, focusing on 

diet-related changes to isolate the impact of diet change on resource use throughout the food system. 

In the final section we outline a more general approach to incorporate the other main factors affecting 

resource use in the food system—population and technology. We find that several ERS models provide 

useful frameworks for a broader empirical analysis of sustainable pathways to producing a healthy and 

adequate food supply that accounts for population and technology change.

1Calculated from the ERS Loss Adjusted Food Availability data product (USDA-ERS, 2019) using data from the total average daily per capita calories series (adjusted for spoilage and other waste) and the ERS estimate of resident plus Armed Forces 

population series.
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p0 ^ �0 

� � Change in

resource use � � Change due to average diet � � Change due to population � � Change due to technology

Conceptual Framework

Total resource requirements of national food systems are determined by three main factors:2

a. Population (p) - how many total residents?

b. Diet (D) - what will the ‘average’ resident consume?

c. Technology (T) - how will the food system make, market, and preserve food supplies?

Measures of population in vector p are broken out into ‘c’ different cohort groupings based on 

the various factors that influence diet choices—for example, a simple breakout by gender across 8 

different age ranges. For each cohort grouping row in matrix D, average diets are measured across 

‘y’ columns representing different food commodity groupings—for example, 74 different broad food 

and beverage commodity groupings, such as ‘fresh fruits.’ For each food commodity row in matrix T, 

average resource use per unit of commodity consumed is measured across ‘r’ columns representing 

different types of natural resource materials or services—for example, fresh groundwater withdrawals—and further broken out across ‘s’ supply chain stages—for example, use for crop production—for a total of r × s different matrix columns. To use the data in p, D, and T to measure how use 

of all natural resources (R) for food production changes over time, the role of these three main factors 

can be stated mathematically as follows:

1) ∆R ≈ � � × ∆D × T0

� + �∆p × D0 × T0 � + � p × D0 × ∆T� 

In equation (1), the upper-case Greek delta (Δ) denotes the measurement of change over a fixed time 

interval—for example, change over one minute, day, year, decade, etc.—and the zero superscript (0) 

denotes a measurement in the current time period. If we denote the future period that is one interval of 

time after the current period with a ‘1’, then the change in per capita diet expression in (1) is measured 

as ΔD = (D1 - D0). The symbol ‘^’ above p (in change due to population) indicates the vector is 

changed into a diagonal matrix, which allows for the matrix multiplication of all expressions on the 

right side in (1) to produce the desired measures of change over time in total use of natural resources.

Equation 1 is only an exact measure when considering very small intervals of time. When considering other than small units of time we use the symbol ‘≈’, which means ‘is approximately equal to’. 

An example of this approach by Canning et al. (2010) examined historical data to decompose how 

changes in the use of energy throughout the U.S. food system between 1997 and 2002, measured in 

British thermal units (Btu’s), was influenced by the three measures on the right side of equation (1). 

2Along with these main factors, a number of external factors are important, including, for example, climate change, changes 

in international terms of trade, and natural disaster, to name a few.
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They found that change due to technology (ΔT) explained about half of the overall change and that 

changes due to diet (ΔD) and population (Δp) both explained about a quarter of the overall change. 

We focus on diet change (ΔD). This term is in the first bracketed expression on the right side of 

equation (1), which also includes terms for the population and technologies in place during our baseline period of analysis, p0 and T0. This approach of only considering scenario changes to one term at 

a time is called comparative static scenario analysis. Although this report does not conduct comparative static scenario analysis of population change or technical change, we follow our scenario analysis of diet change with a discussion of a more general framework for studying these other two main 

factors, Δp and ΔT. Our focus is on the use of domestic natural resources to accommodate food 

demand in the United States.
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How Do We Determine American Diets?

This analysis focuses in particular on the natural resource implications of a change from typical 

American diets to diets aligned with the Dietary Guidelines for Americans (DGA). It is consistently 

shown that U.S. dietary patterns do not align with the DGA (USDA and USDHHS, 2015). For 

example, many Americans exceed the Federal dietary recommendations for added sugars, saturated 

fats, and sodium, and could improve their eating patterns by increasing consumption of vegetables, 

fruits, and dairy (Figure 2-1 in USDA and USDHHS, 2015). 

To represent the typical American diet, denoted as the Baseline diet, we used the 2007–08 National 

Health and Nutrition Examination Survey (NHANES) collected by the National Center for Health 

Statistics (USDHHS CDC NCHS, 2013a). NHANES is a nationally representative survey designed 

to assess the health and nutritional status of Americans and is released in 2-year cycles. The dietary 

data were collected through interviews in which respondents recalled what they ate in the previous 

24 hours (USDHHS CDC NCHS, 2013b). As explained below, we use data from 2007-08 for 

consistency with other data sources available for use in the analysis. We compare the diets of respondents in the 2007-08 NHANES sample with the 2010 Dietary Guidelines for Americans and employ 

a model that estimates the most likely food intake by the respondents whose diets were consistent 

with all the guidelines.3 This model-derived intake becomes the Healthy American diet scenario. 

This diet is derived from a model with nutrient, food pattern, and caloric targets for the moderate 

physical activity level (Appendix 6 in USDA and USDHHS, 2010).

Building on previous work by Canning et al. (2017) and Rehkamp and Canning (2018), the Healthy 

American diet is derived from a mathematical optimization model designed to minimize the difference between the Baseline diet and one that meets the DGA recommendations (USDA and USDHHS, 

2010). We use 16 cohort populations that represent all Americans ages 2 and above, broken out by 

gender across 8 age ranges (see Appendix table A.3 in Canning et al., 2017). The maximum likelihood 

properties of the model we use to derive the Healthy American diet are the most representative diets 

among Americans who are aligned with the DGA. In terms of an underlying theory of consumption, 

this diet is most representative of the underlying preferences of U.S. consumers meeting all dietary 

guidelines as of 2007, given prevailing prices and incomes at the time across the 16 different cohort 

groups. Diets meeting the DGA represent healthier eating patterns than average American diets, and 

these recommendations aim to “help promote health and prevent chronic diseases for current and 

future generations” (USDA and USDHHS, 2015). This motivates our use of the Healthy American 

diet as our representative alternative diet scenario.4

The model’s dietary constraints include food group guidelines, defined by the USDA Food Patterns. 

The USDA Food Patterns recommend consumption amounts for each food group for 12 different 

calorie levels and serve as examples of how to follow the DGA (USDA-ARS, 2014). We also include 

caloric and 33 nutrition targets, all of which are outlined in the 2010 DGA appendixes (USDA and 

USDHHS, 2010). The nutrient targets are included for completeness, since the most nutrient-dense 

foods are not typically chosen by Americans (Britten et al., 2012). These dietary constraints are 

3In our related research (e.g., Rehkamp and Canning, 2018; Hitaj et al, 2019 ), we compare our results to those of others 

in the literature who also used the 2010 DGA as a yardstick to measure healthy diets (Heller and Keoleian, 2015; Tom et al., 

2016). We found only minor differences in diets when using the more recent 2015-2020 DGA (USDA and USDHHS, 2015) 

as a yardstick to measure healthy diets.

4The focus here on a single hypothetical alternative diet scenario can routinely be expanded to a range of potential diets, 

such as was done in Hitaj et al. (2019).
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weighted based on the age and gender demographics of the NHANES participants. In addition to the 

dietary constraints, we also imposed a cost constraint requiring that the wholesale cost of the Healthy 

American diet be the same as or less than that of the Baseline diet. We allow a ±5-percent deviation 

from the caloric targets to give the model flexibility to solve. Overall, calories in our Healthy American 

diet are higher than in the Baseline diet but still within the calorie constraints. More technical details 

of the diet model and data sources can be found in Canning et al. (2017).

The Healthy American diet resulting from solution of the model is the shortest and least disruptive 

route to eating healthfully. Statistically, it is most representative of American diets meeting the DGA 

because of the model’s construction. Because of the model’s minimum-change objective, the Healthy 

American diet contains many of the same food items as the Baseline diet. For example, fluid milk, 

bananas, and tortillas are popular food items in both diets, but the quantities of the food items vary. 

Figure 1 summarizes the national average diets of all Americans for the two diets—Baseline and 

Healthy American. The summary measures are daily per capita caloric consumption across nine broad 

food categories that group the individual food items from NHANES that make up the two diets. 

Figure 1

Per capita calories by food group: Baseline and Healthy American diets

Note: Baseline diet is measured from the 2007–08 National Health and Nutrition Examination Survey (NHANES) (USDHHS 

CDC NCHS, 2013a)—a nationally representative survey of food intake by all Americans ages 2 and above. Healthy American 

diet is from a model that estimates the most likely food intake by all Americans in the 2007–08 NHANES sample who are

meeting all 2010 USDA dietary guidelines (USDA and USDHHS, 2010).

Source: USDA, Economic Research Service.

 
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In moving from the Baseline diet to the Healthy American diet, the largest percentage reductions 

in consumption occur in the two categories, sugars/sweets/beverages and fats/oils/salad dressings, 

while the largest increases are for legumes/nuts/seeds and both fruits and vegetables. These overall 

shifts are consistent with our expectations on how diets would have to shift to be aligned with the 

DGA. In addition to caloric changes in overall food categories, there are within-category shifts of 

individual food items, changing dietary composition.

Differences between the two diets are substantial, which portends potentially large differences in use 

of the various natural resources required to accommodate each of them. Before we present measures 

of resource requirements, we discuss our approach to identifying and estimating these measures.
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How Do We Identify and Measure Resources in the 

U.S. Food System?

We apply a consistent approach to identifying and measuring resource use and impacts across all 

markets and for all types of resources. Using our recently published research on this topic and new 

analysis, we are able to compile and synthesize diet/resource scenario analysis of a major metric for 

each of the five natural resource categories.5

Our approach is unique in that we estimate resource use directly at each point in the food supply 

chain using three data-rich models. We combine a diet model, an environmentally extended inputoutput model of resource use in the food system, and a biophysical model of land use for crops and 

livestock to estimate resource use across alternative diet outcomes. The integrated analysis links 

the diet choices of 16 different age/gender cohort populations over 4,000 food items, as reported 

in NHANES, to food purchases across over 70 commodity groups, to food production directly and 

indirectly involving over 300 industry groups, to resource use across the 5 categories. The limiting 

data source for this purpose is data for the production model, which must link the resource data 

on the input side to the food expenditure data of households and foodservice establishments on the 

output side. At the time of the recent ERS analysis that this report builds on, the 2007 National 

Benchmark Make and Use Tables published by the Bureau of Economic Analysis (USDOC BEA, 

2015) provided the latest data of sufficient detail for this purpose, so our analysis of observed conditions is represented by the 2007 U.S. food system.

Which Resource Materials and Services Are Important to Food 

Production?

To produce the food that Americans consume each day, food system businesses employ workers to 

use their machinery and equipment, buildings, and purchased materials and services from other food 

system businesses. With these, the businesses produce outputs that are either consumer food products, such as plain nonfat yogurt, or are a product that they sell for use by other food system businesses, such as veterinary services sold to a dairy farm. 

In addition, many of the food system establishments use materials and services provided from the 

country’s endowment of natural resources. In terms of physical attributes, natural resources can 

be classified into five categories: land, water, air, minerals and forests.6 To illustrate how these 

different natural resources are used in food production, consider the following example: Mining 

businesses extract potash, a mineral containing potassium. Farmers growing crops, such as wheat 

farmers, purchase potash products to fortify the plant nutrients embodied in the soils of their farmland in order to improve their wheat yields. The potash is material from the mineral group of natural 

5This report synthesizes four primary publications on sustainable diets (Canning et al., 2017; Hitaj et al., 2019; Peters et 

al., 2016; Rehkamp and Canning, 2018). However, there is a burgeoning body of literature and interest in the environmental 

impacts of dietary patterns both in the United States (e.g., Boehm et al., 2018; Heller and Keoleian, 2015; Tichenor Blackstone et al., 2018; Tom, Fischbeck, and Hendrickson, 2016) and globally (e.g., IPCC, 2019; National Academies of Sciences, 

Engineering, and Medicine, 2019; Tilman and Clark, 2014; Willet et al., 2019).

6In this classification, minerals include fossil fuel materials, and forests are used instead of the more general ‘vegetation 

and animals’ since the latter also describes important intermediate products (crops and livestock) of the food system. The 

boundary of our analysis for land use is agricultural land, and so it excludes, for example, the use of land for food-related forest product production and the mining of fossil fuels.
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resources, and the soil is material from the land-resource group. Major customers of the wheat farmers 

are flour mills that operate electric milling and packaging machinery to convert the purchased wheat 

into flour, which is then often packaged in paper products. The paper is made from wood pulp, a 

material from the forest resource group. The electricity that powers the mill is most likely produced 

by a process in which freshwater is diverted from a waterbody and heated with a fuel such as coal to 

create steam under high pressure to spin a turbine that produces electricity. The freshwater is a material from the water resources group and coal is from the minerals group. Two byproducts of electric 

power production are steam from the boiling of water and carbon from the burning of coal, which are 

discharged into the air. In this case, air (one of the resource groups) is providing disposal services.

But just as a flour mill requires a certain quality of wheat, businesses require natural resource materials and services of a minimum quality. Resource quality and availability is naturally managed and 

regulated by resource cycles, such as the water, carbon, and soil nutrient cycles. (See box, “Natural 

Resource Use in the U.S. Food System: An Overview” for an overview of the materials, services, and 

key cycles important to our food system.)

Recent research by ERS and our partners assesses how some materials and services that are important to 

the food system are used to accommodate baseline and alternative American diets. We synthesize findings from these studies with new analysis using existing ERS models and data (see Appendix Table 1 for 

a list of the materials and services studied and the case studies or ERS models this analysis draws from).

How Is Resource Use Measured in the U.S. Food System?

To measure resource requirements in the U.S. food system, ERS economists developed the Food 

Environment Data System, or FEDS (Canning et al., 2017). FEDS is a national data system 

that follows the material flows accounting framework adopted by the United Nations Statistical 

Commission (United Nations et al., 2014). While economists often study dollar units (i.e., prices or 

cost), FEDS also incorporates physical units of measurement. We are able to comprehensively estimate resources used throughout the food supply chain from the production of farm inputs, crops, 

and livestock through points of consumer food purchases and to the operation of home kitchens. For 

example, we can estimate total water use associated with a hamburger, such as the cattle’s drinking 

needs, irrigating the crops that become livestock feed, water used in electricity generation that ultimately runs the refrigerators at the grocery store, and water for rinsing dishes in the kitchen sink. In 

this report, the terms water use and water withdrawals are used interchangeably. Both refer to water 

removed from the ground or diverted from a surface-water source for use.7

Detailed descriptions of FEDS data sources, and how the environmental input-output model, called 

FEDS-EIO, is used for the analysis in this report are summarized in our technical appendix (see 

section “Measuring Diet-Related Fossil Fuel Combustion and Water Withdrawals”).

To account for land use in alternative diets in this report, we use a biophysical simulation model that 

calculates the per capita land requirements of complete diets and the potential carrying capacity of 

the agricultural land of the conterminous United States (Peters et al., 2016). The land requirement per 

gram of each food commodity consumed accounts for food loss and food waste occurring in preparation, distribution, and processing, but does not allow for technological change or productivity growth. 

7Not all water use is a consumptive use, including water that is evaporated, transpired, or incorporated into products or 

crops, consumed by humans or livestock, or otherwise removed from an immediate water environment (see glossary in Dieter et 

al., 2018).
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It also does not account for nonagricultural land use, such as for the production of forestry products 

or the mining of fossil fuels. Estimates for each food commodity in the diet are calculated based 

on nationally representative estimates of crop yield, grazing land productivity, and livestock feed 

efficiencies. The model adjusts for the multi-use nature of certain crops (e.g., soybeans produce 

vegetable oil and high-protein livestock feed) and prevents double-counting. These per gram land 

requirement calculations are applied to both the Baseline and Healthy American diets. Two revisions were made to the model for this study in order to measure livestock inventories linked to 

alternative diets. A detailed description of data sources and how the biophysical model, called 

Foodprint, is used for the analysis is reported in our technical appendix (see section “Measuring 

Land Use and Farm Animal Inventories”). Unlike the other resources considered in this report, our 

metric for land-acres--is not homogenous from a productive standpoint, and our current approach 

does not capture potential heterogeneities.8

Air is used as a repository for GHG emissions from both fossil fuel combustion in food production and from biogenic sources, including enteric fermentation and manure management emissions 

from livestock and soil management emissions from cropland. The Foodprint model gives the 

land requirements used to compute soil management emissions from both food and livestock feed 

production, as well as livestock inventory to calculate enteric fermentation and manure management 

emissions. GHG emissions from fossil fuel combustion are calculated from energy consumption by 

fuel, production stage, and subsector tracked through FEDS-EIO. The section “Measuring Air Use 

as a Repository for GHG emissions” in the technical appendix describes the data sources used for 

calculating GHG emissions associated with different diets.

Our approach to measuring use of forest products by supply chain stage is to develop value-added 

measures. This measure simply represents the monetized value of physical units for forest products. 

For this purpose, we employ the ERS Food Dollar model (Canning, 2011; Canning, Weersink, and 

Kelly, 2016). A detailed description of data sources and how the model is used for the analysis in 

this report is provided in our technical appendix (see section “Measuring Forest Product Use”).

8A potential future refinement could be to develop productivity-weighted estimates of land use changes.

Natural Resource Use in the U.S. Food System: An Overview

Materials and services across all five natural resource categories are important inputs to the 

production, marketing, preparation, and disposal of food purchased by or for all Americans. 

These five natural resource categories are land, water, air, minerals, and forests.

Land: This resource provides suitable soils for use in growing food, feed, and fiber crops and 

provides space for grazing and tending farm livestock (Peters et al., 2016). Land also provides 

space for structures of all types used throughout the food system, plus for roads and other transportation infrastructure that connects nodes in the food system. It is a place for disposal of 

managed waste1 from production and consumption (usually for a fee, such as in landfills), and 

is also a repository for material byproducts of production and consumption other than managed 

1“Managed waste” refers to byproducts of production and consumption that the producer or consumer does repurpose 

or does purposefully and legally reposit (put away or store up).

continued
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waste (usually with no fee, such as through runoff and soil leaching). Soil health, which is essential 

to achieving high crop yields, is naturally regulated by the soil nutrient cycle and can be enhanced 

through use of best-management practices (Bowman, Wallander, and Lynch, 2016). 

Water: Freshwater is necessary for human consumption and is also used throughout the food system 

as a production input (including household production) for purposes including crop irrigation, livestock servicing, thermoelectric power generation, various industrial uses, and food preparation and 

cleanup (Rehkamp and Canning, 2018). Sources of freshwater withdrawals include surface and 

groundwater origins. Like land, waterbodies provide a place for disposal of managed production 

and consumption waste (sometimes for a fee, such as through issuance of point-source discharge 

permits), and also serve as a repository for unmanaged waste (usually with no fee, such as through 

non-point-source waterbody discharges (Ribaudo, Horan, and Smith, 1999). Water quality must be 

maintained for productive uses, and quality is naturally regulated by the water cycle.

Air: Air is a free resource that nonetheless provides vital materials and services throughout the food 

system. For example, oxygen and nitrogen manufactured using air separation processes have many 

industrial uses important in food production, such as agricultural fertilizers, steel manufacturing, 

and refrigerants. Air is also a repository for byproducts of fossil fuel consumption throughout 

the food system (Canning et al., 2017), and is both a source of key elements and a repository for 

byproducts of processes like enteric fermentation of livestock and manure and soil management 

(Hitaj et al., 2019). Air quality is essential to sustain life and maintain high productivity throughout 

the food system. One important natural regulator of air quality is the carbon cycle,2 which includes 

the process of photosynthesis, whereby green plants use energy from sunlight to remove carbon 

from the air and replace it with oxygen.

Minerals: Minerals are naturally occurring inorganic substances that are typically obtained 

commercially from underground deposits. Commercially viable mineral products have properties 

that add value to a production process or are marketable as a consumer good. Examples of mineral 

products used throughout the food system include calcium, fossil fuels (refined crude oil products, 

coal products, and natural gas), metal products, phosphate, potash, and salt. The time it takes 

for new minerals to form is far longer than the human lifespan, and so mineral use is managed 

as a nonrenewable resource; minerals are used within the framework of optimal extraction with 

depletion and discovery (Conrad and Clark, 1987). For example, if we ignore the possibility of 

new mineral discoveries, then mineral use today reduces the total future availability of that same 

mineral by an equal amount. In this case, increasing a mineral’s use in production today should 

only occur if the value it creates today exceeds the present (discounted) value of all possible future 

uses. That determination is typically made by the mineral owner. 

Forests: Forest products used throughout the food system include lumber used as building material, 

paper products used as packaging and for office supplies, and both plant and animal food products. 

Forests are a renewable resource that is naturally managed by the forest life cycle3 and are further 

managed through forestry best-management practices for either commercial or recreational-conservation purposes. Forests also play a major role in the carbon cycle, serving as a carbon reservoir and 

as a supplier of oxygen into the atmosphere (Lewandrowski et al., 2004).

2https://www.nrs.fs.fed.us/carbon/. 

3www.oregonloggers.org/Forest_About_FullCycle.aspx.
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Results of Food Demand Scenarios

In the following comparative static scenario analysis, we consider diet-related changes and the 

associated adjustments in the use of natural resources—the first bracketed term in equation (1). 

This analysis holds population of the 16 cohort groups at their baseline levels (p0) and assumes the 

baseline production technologies (T0) for all possible diet outcomes. The purpose is to isolate the 

impact of diet change on resource use throughout the food system. In the next section we consider, 

but will not carry out, a more general approach to study the other main factors affecting resource 

use in the food system (ΔD and ΔT).

Total Resource Requirements of the Baseline Diet

We synthesize and adapt research from five technical publications (Canning, 2011; Canning et 

al., 2017; Hitaj et al., 2019; Peters et al., 2016; Rehkamp and Canning, 2018) to answer the question, What share of key domestic natural resources used throughout the economy is dedicated to 

accommodating observed (2007) American diets? The results are summarized in Figure 2. 

Figure 2 

Estimated annual resource use in the Baseline diet across five categories, 2007

Btu=British thermal units. GDP=gross domestic product.

Note: Baseline diet is measured from the 2007–08 National Health and Nutrition Examination Survey (NHANES) (USDHHS 

CDC NCHS, 2013a)—a nationally representative survey of food intake by all Americans ages 2 and above.

Source: USDA, Economic Research Service.

Total 2007 U.S. resource use and the food system’s (Baseline diet) share

Diet related Diet related Non-diet related Non-diet related

25.5%

28.0%

11.5%

18.1%

7.2% 8.6% 0.0

100.0

Total land

area (acres)

Freshwater

withdrawals

(gallons per day)

Fossil fuel

energy use

(Btu)

Greenhouse

gas emissions

(metric tons CO2eq)

Forest 

product

use ($)

Diet

contribution

to GDP ($)

8.6

2.3

billion

349

billion

85.9

quadrillion

7.4

billion

22.4

billion

14.4

trillion
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Total annual expenditures on food in the United States were 8.6 percent of U.S. gross domestic 

product (GDP) in 2007.9 We consider any natural resource having greater than 8.6 percent of 

its 2007 domestic use dedicated to food an intensive use of the resource by the food system. 

This is a relative measure that is similar in concept to the Heckscher-Ohlin (H-O) theorem 

of factor-abundance (see Chapter 11 in Blaug, 1992). An important concept of material-flows 

accounting (Bullard and Herendeen, 1975) leads to an accounting identity that 100 percent of 

all ‘materials’ used as production inputs throughout the economy, including natural resources, 

are embodied in real gross domestic product (GDP). Because our analysis is only for 1 year, 

nominal GDP is an acceptable substitute for real GDP. It is a straightforward calculation to 

show how any category of GDP—such as food, whose national share of resource use exceeds 

its national share of real GDP—is an intensive user of that resource, based on this H-O type 

measure for intensive use.

It is important to note that all embodied resources measured here only represent those used 

domestically for the purpose of accommodating all annual food and beverage purchases of the 

entire U.S. population, ages 2 and above. This does not include resources used for farm and 

food production for the export market and farm production for the nonfood domestic market. 

It also does not include resource use in other countries for the production of food and ingredients imported to the United States and purchased by U.S. food consumers, although it does 

include the resources used to transport and market these imports once they enter the country. 

Finally, it does not include the resources used to produce the food and beverages purchased by 

Americans traveling abroad. The focus here is to measure the share of each domestic annual 

resource budget (in physical units) that is dedicated to accommodating annual 2007 diets of 

all Americans ages 2 and above. When alternative diets are considered in the model, production coming from both domestic and imported sources adjusts to the new diet requirements 

by amounts that maintain their market shares. For example, should the new diet require a 

5-percent decrease in total cheese production, then the sale of both domestic and imported 

cheeses to U.S.food consumers declines by 5 percent.

Results indicate that to accommodate all U.S. diets in 2007, the U.S. food system used 25.5 

percent of the country’s nearly 2.3 billion acres of total land area, including over half (53 

percent) of productive agricultural land. This finding partially reflects the fact that much of 

U.S. cropland is devoted to nonfood crops, like cotton and corn for ethanol, and to export 

crops, like soybeans. The U.S. food system also used 28 percent of total freshwater withdrawals, 11.5 percent of the country’s 85.9 quadrillion British thermal unit (Btu) annual fossil 

fuel budget, 18.1 percent of the roughly 7.4 billion metric tons of annual greenhouse gas 

(GHG) emissions, and 7.2 percent of the $22.4 billion of marketed forest products. With the 

exception of forest products, each was an intensive use of the resource by the food system.

Figure 3 provides a closer look at diet-related resource use. Of the productive agricultural land 

dedicated to the Baseline diet, grazing land represents the largest portion—its 397-million 

acre requirement represents about 36 percent of total productive agricultural land and 54 

percent of total grazing land use. Diet-related perennial forage cropland (land with herbaceous 

crops that are alive year-round, such as alfalfa and other hay crops fed to livestock) totaled 91 

million acres and—while only representing about 8 percent of productive agricultural land—

9The Baseline diet is facilitated by domestic food expenditures. Food GDP in 2007 is measured as the sum of line 

26 (Food and beverages purchased for off-premises consumption) plus line 82 (Food services) of table 2.4.5 of the 

National Income and Product Accounts (NIPA). Total GDP in 2007 is from line 1 of NIPA’s table 1.1.5. (https://apps.

bea.gov/iTable/index_nipa.cfm accessed on December 4, 2018).
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accounted for 92 percent of all U.S. land used for perennial crops in 2007. Diet-related cultivated cropland totaled about 90 million acres, also representing about 8 percent of productive 

agricultural land and 35 percent of all U.S. land used for cultivated crops.

Figure 3

Detailed annual resource use estimates attributable to the Baseline diet, 2007

Note: Freshwater withdrawals refer to freshwater removed from the ground or diverted from a surface-water source 

for use; freshwater withdrawals may be different from freshwater consumption. Biogenic emissions include enteric 

fermentation (the digestive process of ruminant livestock such as cattle) and manure management emissions from 

livestock and soil management emissions from cropland. Baseline diet is measured from the 2007–08 National Health 

and Nutrition Examination Survey (NHANES) (USDHHS CDC NCHS, 2013a)—a nationally representative survey of 

food intake by all Americans ages 2 and above. 

Source: USDA, Economic Research Service.

For freshwater, about 70 percent of food-related withdrawals came from surface water sources, 

with the remainder coming from groundwater. According to data from the U.S. Geological 

Survey (2005), over 75 percent of all freshwater withdrawals in 2005 were from surface water, 

which indicates that the U.S. food system is somewhat more reliant on groundwater sources than 

the nonfood economy. 

Among sources of GHG emissions from the use of fossil fuels by households, businesses, and 

Government, 14 percent are attributed to the Baseline diet, whereas diet-related biogenic emissions of methane and nitrous oxide account for 44 percent of the U.S. total methane and nitrous 

oxide emissions in 2007. Overall, biogenic GHG emissions associated with the Baseline diet 

account for 5.9 percent of U.S. total GHG emissions. There are a number of agriculture-related 

GHG emissions that we do not account for by design, such as emissions related to the production of cotton or biofuel feedstocks or emissions related to the domestic production of food 

items exported to other countries. Thus, our estimate of biogenic GHG emissions accounting 

for 5.9 percent of U.S. total GHG emissions is lower than the 8.1 percent estimate for 2007 by 

the U.S. Environmental Protection Agency (U.S. EPA, 2017b). 

 
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Resource-Use Comparisons at Different Supply Chain Stages 

A supply chain analysis allows us to study the accumulation of resource use over the life cycle of 

specific domestic food commodity value chains from farm production through processing, packaging, distribution, marketing, and final food preparation and cleanup—both in home kitchens and 

at foodservice establishments. In addition, energy services are accounted for separately in the case of 

freshwater withdrawals and forest products due to the importance of these two resources in energy 

production. Knowing where resource use accumulates is fundamental to understanding what factors 

influence resource-use decisions. An interesting finding from the supply chain analysis is that the 

stages found to be most reliant on resource inputs differ substantially across the five resources considered. These findings are summarized in Figure 4, where the cumulative shares of total resource use 

are charted on horizontal stacked bar graphs, beginning with farm production (including farm inputs) 

on the left and culminating with household production (home kitchen operations plus travel to points 

of purchase) on the right.

The bottom two horizontal stacked bar columns depict agricultural land use and freshwater withdrawals. For these resources, the bulk of diet-related resource use occurs on-farm. Agriculture is the 

major land user in the United States. In 2007, agricultural uses occupied approximately 1.2 billion 

acres, 51 percent of all U.S. land and 61 percent of land in the lower 48 States, where nearly all agricultural land occurs (Nickerson et al., 2011). This analysis focuses on “productive agricultural land,” 

which includes all cropland harvested for crops or used to pasture livestock, all grassland pasture and 

range, and forestlands used for grazing. It constitutes the vast majority of agricultural land, approximately 1.1 billion acres. The remaining fraction of agricultural land is made up of idle cropland, 

including land enrolled in the Conservation Reserve Program, fallow cropland, failed or abandoned 

crops, farmsteads, and farm roads. For freshwater withdrawals, it is not surprising that agriculture is 

the dominant user due to irrigation, but perhaps it is surprising that slightly over a third of water use 

in the Baseline diet occurs post-farmgate, including in household kitchen use (20 percent) and in the 

energy industry (12 percent). By comparison, water use at the processing and packaging and the distribution and marketing stages is relatively small.

Agriculture accounts for less than half of total diet-related resource use among the other three 

resources depicted in Figure 4, with little else in common among them. Fossil fuel use increases 

from left to right along its stacked horizontal bar, indicating that fossil fuel use for farm production 

(including inputs such as fossil fuels used in the production of chemical fertilizers) is the first and the 

smallest user in the life cycle of food, and households are the last and largest user for fossil fuels. Over 

40 percent of GHG emissions in food production are from sources other than fossil fuel and largely 

emanate from agriculture. Enteric fermentation from the digestive process of ruminant livestock such 

as cattle emits methane (CH4), while manure management results in both methane and nitrous oxide 

(N2O) emissions (U.S. EPA, 2017a). Soil management results mainly in nitrous oxide emissions, 

though rice cultivation is a source of methane emissions. After agriculture, the largest share of GHG 

emissions comes from households, followed by distribution and marketing. For forest products, the 

greatest use occurs during processing and packaging, with packaging accounting for most of this total.
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Overall, the results summarized in Figure 4 show that resource use linked to Baseline diets extends 

far beyond agriculture and that the patterns of use by supply chain stage vary across the five 

resources considered. A critical question that we next turn to is whether conservation goals can be 

achieved across all five resources through changes in diet alone, or if there are tradeoffs in conservation outcomes among the resources.

Figure 4

Share of estimated total resource use by U.S. food system supply chain stage for 

Baseline diet

Note: Baseline diet is measured from the 2007–08 National Health and Nutrition Examination Survey (NHANES) (USDHHS 

CDC NCHS, 2013a)—a nationally representative survey of food intake by all Americans ages 2 and above.

Source: USDA, Economic Research Service.

Evidence of Synergies and Tradeoffs in Food Demand Scenarios

The previous sections detailed resource use associated with the Baseline diet, which we used to 

compile our FEDS-EIO and Foodprint models, since that scenario represents the status quo for the 

period of analysis. In this section,s we conduct the same analysis for the Healthy American diet and 

compare resource use between the two diets.10 Specifically, for each of the five natural resources we 

measure the percentage change to total use in going from the Baseline to the Healthy American diet. 

With resource conservation as the objective, a measured decline in use of a resource indicates it is 

synergistic with a shift to the Healthy American diet. The results are reported in Figure 5.

10For the comparative static scenario analysis, we model the food system supply chain stages except for households, since 

we do not know how household resource use would change with different diets.

 
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Productive agricultural land use declines slightly over 3 percent, about 19 million acres, using the 

assumptions associated with a Healthy American diet. This acreage reduction is roughly equal to the 

total land area of South Carolina.11 In particular, grazing land and perennial cropland use decline by 

about 13 and 8 million acres, respectively, while cultivated cropland use increases by about 2 million 

acres. The effect of the overall reduction in agricultural land use on resource conservation depends on 

what happens to the land taken out of agricultural production. The reduction in grazing land and perennial cropland could result in improved environmental outcomes, for example, if the land is enrolled in the 

Conservation Reserve Program. If it is instead converted to developed land with buildings, the environmental effect of this land-use change would likely be negative, resulting, for example, in a loss of wildlife 

habitat. The increase in cultivated cropland, if it comes from less-intensive land uses such as grazing land, 

would likely result in an increase in environmental costs, such as greater erosion potential and a loss of 

sequestered soil carbon; the net effect, however, would hinge on the types of practices put in place on the 

converted land (e.g., conventional versus conservation tillage).

Fossil fuel use is found to be synergistic with a conversion to the Healthy American diet. The finding 

that fossil fuel use declines by 3 percent is based an assumption that fossil fuels remain a constant 

share of total food-related energy use in both diets and a finding that overall energy use (including 

nuclear power and renewable sources) declines 3 percent. A 3-percent decline of total diet-related 

energy use in 2007 equals the reduced gasoline consumption that would occur if 3.7 million automobiles were removed from use for 1 year. 

Figure 5 

Estimated percent change in resource use going from Baseline to Healthy American diet

Btu = British thermal units. Note: Baseline diet is measured from the 2007–08 National Health and Nutrition Examination Survey 

(NHANES) (USDHHS CDC NCHS, 2013a)—a nationally representative survey of food intake by all Americans ages 2 and 

above. All diets are linked to the annual 2007 U.S. personal consumption expenditures on food (BEA, 2015). Healthy American 

diet is from a model that estimates the most likely food intake by all Americans in the 2007–08 NHANES sample who are meeting all 2010 Dietary Guidelines for Americans (USDA and USDHHS, 2010). 

Source: USDA, Economic Research Service.

11Total area within the State boundary minus perennial water area, as reported by the Census Bureau (U.S. Census Bureau, 

unpublished data from the MAF/TIGER database), using a conversion rate of 640 acres per square mile.

Percent change from Baseline diet

-3%

16%

-3% 0%

-9%

-10

0

10

20

Agricultural

land

Annual 

freshwater 

withdrawals

Annual fossil

fuel energy

use

Annual 

greenhouse

gas emissions

Annual forest 

product

 use

(77.8 billion 

gal/day)

(577 million 

acres)

(6.4 quadrillion

Btu)

(1.3 billion metric

tons CO2

eq)

($1.5

billion)
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Another natural resource found to be synergistic with a conversion to the Healthy American diet 

was forestry. A 9-percent reduction in annual forest product use was measured in terms of production value. A conversion of this measure to volume (ft3) is obtained by assuming that the average 

roundwood equivalent price per unit of forestry and logging products purchased for diet-related uses 

was the same as the average price across all uses. Under this assumption, the reduction in use of 

forest and logging products with a conversion to the Healthy American diet was 1.6 billion ft3. For 

perspective, this volume is 11 percent of total domestic production of timber products (15 billion ft3) 

in 2007 (Howard and Jones, 2016).

Freshwater withdrawals increase 16 percent with a transition from the Baseline to the Healthy 

American diet.12 This increase translates to the additional average daily freshwater withdrawals of 

12.1 billion gallons. The largest production increases with a conversion to the Healthy American

diet occur among fruit, vegetable, legume/nut/seed, and dairy products (Figure 1), and the arid U.S. 

West accounts for a dominant share of total domestic production of the farm commodities embodied 

in these products (Parr et al., 2018; Perez and Plattner, 2015).

Use of air as a repository for diet-related GHG emissions declines only minimally (-0.4 percent) 

with a conversion to the Healthy American diet. Reductions in GHG emissions from the production 

of sugars, sweets, and beverages are offset by increased emissions from dairy, fruit, vegetable, and 

nut production.

Overall, we find mixed relationships among the five natural resources studied. There is a potential 

for both synergistic and opposing relationships among conservation and nutrition goals—both USDA 

priorities. These findings are important and informative to a consideration of resource requirements 

of food demand in the United States. In the next section, we discuss the implications of our findings 

in the context of a broader assessment of how population and technology change could be accounted 

for in a more complete assessment of resource requirements for accommodating U.S. food demand.

12The prospects for such an increase are constrained by other factors, such as water availability and institutions governing 

access. This is particularly so for the arid West, where a significant share of U.S. specialty crop production is concentrated.
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Future Directions

A future extension of the analysis presented above is to link the diet model, the economic model, 

and the biophysical model, still within the comparative static framework, and perform a multi-objective optimization study. That is, we could minimize the use of one natural resource while meeting 

DGA and cost targets and evaluate how this would affect the other resources, or we could optimize 

outcomes across all resource conservation and nutritional goals simultaneously. For example, in 

Canning et al. (2017), a model was specified to minimize the use of energy inputs while meeting 

national dietary targets. In Rehkamp and Canning (2018), a similar model was specified to minimize 

freshwater withdrawals. Other research within this framework introduces approaches for measuring 

consumer willingness to pay (or be compensated) for marginal changes in diets (Irz et al., 2016), 

and the social value of changes to the use of either a single resource (IWGSCC, 2015) or of multiple 

resources (Gustafson et al., 2016). Incorporation of these extensions, or variations that can be validated with U.S. specific market and nonmarket valuation information, would facilitate a more general 

optimization model to quantify the optimal mix of conservation and nutrition outcomes across 

multiple household groupings and for numerous natural resources. Given the spatial nature of land and 

water resource availability and quality, and the many region-specific factors governing resource use, 

regional-scale analysis could potentially help inform the national assessment.13

As discussed, nearly one-half of farmland use is dedicated to production for markets other than U.S. 

food consumers. This includes the export market for U.S. crops and animal products, and both the 

fiber (e.g., cotton) and biofuel (e.g., corn for ethanol) commodity markets. This finding highlights 

the importance of recognizing the role of producer feedback in response to changing market conditions. With reference back to equation (1), this concerns changes to technologies (ΔT). For example, 

figure 1 highlights the differences in consumption between the Baseline and Healthy American 

diets, including a substantial dropoff in the meat, poultry, fish, and mixtures category and substantial 

increases in the fruit and vegetable categories. The fruit and vegetable increases are behind the finding 

of increased freshwater use in the Healthy American diet. But it is not known a priori that animal 

product producers, such as beef cattle operations, will reduce production rather than redirect their 

sales to export markets, or that fruit and vegetable growers will increase the volume of water used for 

irrigation in the same proportions as other production inputs in order to meet the increased consumer 

demand. Alternatively, more fruits and vegetables could be imported. For these reasons, optimization 

models of the agricultural sector that quantify all markets for agricultural production and the associated use of production inputs, including land, water, and other natural resources, are needed to inform 

our understanding of how producers will respond to changing market conditions.14

ERS’s Regional Environment and Agriculture Programming Model (REAP) is an economic model 

that simulates producer crop choice, land use, and price response for the U.S. agricultural sector 

(Johansson et al., 2007). In a recent application (Crane-Droesch, et al., 2019), REAP was used to 

simulate acreage allocation and market price under alternative yield scenarios to determine joint yield 

and price distributions for corn, soybeans, and winter wheat across the country for several climate 

and weather realizations and associated yields. In a similar manner, alternative diet scenarios with their 

13This framework represents a top-down approach that provides a macro/messo-level analysis. Top-down analysis such as 

this is not well-suited for questions often addressed in microlevel LCA (Life Cycle Assessment) studies, such as an analysis that 

distinguishes between brown- versus white-rice consumption. A potential future direction for this line of research might be to 

look at hybrid approaches that combine macro/messo analysis with other bottom-up microlevel analysis.

14Import and export assumptions are especially important here and should be the basis for future extensions.
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associated farm commodity “purchase orders” could be simulated to measure impacts to the same metrics. 

This approach can also be adapted to consider alternative international terms of trade scenarios that allow 

for changing roles of international trade in meeting U.S. domestic food demand. 

As shown in Figure 4, substantial resource requirements occur beyond the farmgate. In a 2010 ERS 

study of energy use in the U.S. food system (Canning et al., 2010), a structural analysis was carried 

out to decompose the main drivers of change in food system energy use between 1997 and 2002—a 

period in which food system-wide energy use increased by over 22 percent. The analysis showed that 

diet change and population growth each explained about one-quarter of the total increase over the 

5-year interval. Technical change explained the other half of the increase and was most pronounced 

among food processors. Energy prices were declining over the 1997 to 2002 period, and, as reported 

in Canning et al. (2017), the food system is very responsive to persistent change in energy prices. 

Computable general equilibrium (CGE) models offer a model framework to account for food systemwide producer feedback and to simultaneously account for consumer feedback in response to changing 

consumer prices and household incomes. In this framework, it is possible to account for the main 

drivers of change in resource use over time—diet, population, and technology.

Canning and Tsigas (2000) develop a U.S. multiregional applied general equilibrium (MAGE) model to 

capture short-run adjustments throughout the U.S. food system and by U.S. food consumers to changing 

market conditions. In this framework it is not possible to impose a national diet outcome, since doing so 

would require the treatment of household decisions as exogenous, which is a disequilibrium scenario. 

However, with sufficient breakout of household cohort groupings representing an array of baseline diet 

profiles, one can exogenously adjust the population counts across cohorts to follow a range of diet evolution scenarios and determine how production and consumption behaviors interact in the face of resource 

and primary production-factor constraints. Like the REAP model, this approach will allow for producer 

feedback in response to changing diet outcomes. REAP provides an unprecedented accounting of agricultural production practices and an array of farm resource-use decisions that are typically not captured 

in the MAGE framework; the MAGE, however, allows for both consumer feedback in response to 

production decisions and vice versa. MAGE also captures resource-use decisions beyond the farmgate, 

which this report has shown to be a substantial share of total food system resource use. 

Both population and productivity are important drivers in determining the role of resource use in the 

food system. The models discussed so far have either ignored these factors or have treated them as 

exogenous factors that can be used to develop alterative scenario analysis. The ERS Future Agricultural 

Resources Model (FARM) is a global computable general equilibrium (GCGE) economic model with 

13 world regions that operates in 5-year steps from 2007 to 2052 (Sands et al., 2017). In the model, land 

use can shift among crops, pasture, and forests in response to population growth, changes in agricultural 

productivity, and policies. Although still not technically a dynamic equilibrium framework, this model 

brings a systematic accounting of the role that productivity and population growth—both in the United 

States and worldwide—can have in determining the potential resource requirements of food demand in 

the United States.

Given the high level of uncertainty about the outlook for production, market structures, and technologies, it is important to develop a range of outlook scenarios and use an array of model frameworks to 

study potential outcomes. In all cases, there is a need for a multimarket, multiresource modeling framework such as the framework presented in this report. However, models with producer and consumer 

feedback are necessary in order to assess how technology adoption affects resource needs of food 

demand. Models are also needed to account for growth in population and productivity. Several ERS 

models are found to provide useful frameworks along these lines.
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Conclusion

By focusing on how diets affect the use of natural resources for meeting food demand, this report 

demonstrates an approach to link food consumption and nutrition data with a diet optimization 

model, an environmentally extended economic model of food production and marketing, and a 

biophysical model to measure land and animal inventory requirements. The diet model uses mathematical optimization to define diets using the attributes of individual food items as consumed by 

Americans. The economic model, FEDS-EIO, accounts for the use of natural resources, and the entire 

food value chain is represented, from farm inputs through home kitchen operations. The biophysical 

model, Foodprint, estimates land and animal inventory requirements of producing all food commodities 

embodied in the model-derived diets.

This report produced several key insights. First, the food system was natural-resource intensive in 

2007. Second, substantial resource requirements occur beyond the farmgate. Third, a healthy diet 

would produce large changes in food purchases and lead to increases in some resource uses and 

decreases in others; Thus, there is a potential for both synergistic and opposing relationships among 

resource conservation and nutrition outcomes. These findings highlight a need for a multimarket, 

multiresource modeling framework to research questions of sufficient scale and scope. Given the high 

level of uncertainty about the future, it is important to develop a range of outlook scenarios and use 

an array of model frameworks. Several ERS models are found to provide useful frameworks along 

these lines.

The various models described in the discussion of future research directions represent frameworks 

of varying dimensions, but they all can be informed by the framework and synthesis of analysis 

presented in this report. Specifically, they address some or all of the factors that are ignored in our 

scenario analysis (which holds everything other than diet outcomes constant) for estimating the 

effect of diets on resource requirements of food demand in the United States. The key insights of 

the analysis and the approach of linking detailed food consumption data, diet models, and biophysical models also apply to each of these extensions and will inform our adaptation of these models 

in future analysis. 
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Technical Appendix: Methods for Measuring Diets, 

Production, and Resources

Materials and services studied, the resource groups they are from, the natural cycles that regulate 

their quality and availability, and a reference to the relevant publications behind this research are 

summarized in the following table. 

Appendix Table 1

Natural resource material and service case studies

Material or 

service

Resource 

group

Unit of 

measurement

Key resource 

cycles

Source of case study or model 

documentation

Suitable soils and 

space

Land Acres Soil nutrient cycle Peters et al., 2014; Peters et al., 

2016

Freshwater Water Gallons Water cycle Rehkamp & Canning, 2018

Fossil fuels Minerals Btu* Nonrenewable Canning et al., 2017

Disposal services 

(GHG)

Air CO2-eq** Carbon cycle Hitaj et al., 2019

Forest products Forests Dollars Forest life cycle; 

Carbon cycle

Canning, 2011; Canning, 

Weersink and Kelly, 2016

*British thermal units. **Carbon dioxide equivalent.

Source: USDA, Economic Research Service.

Brief descriptions of our methodologies and data sources, and/or references to publications where 

methods and data sources are described, follow. 

Modeling Healthy Diets 

See Canning et al. (2017) for technical details of the diet modeling and Rehkamp and Canning 

(2017) for more description of the diets. 

Measuring Diet-Related Fossil Fuel Combustion and Water 

Withdrawals 

Multiregional environmental input-output (EIO) models extend conventional input-output multiplier analysis to consider the physical flows linked to gross domestic product for materials of environmental consequence. Based on the Food Environmental Data System (FEDS), we employ the 

FEDS-EIO model (Canning et al., 2017; Rehkamp and Canning, 2018), which extends the official 

U.S. System of National Accounts (SNA) in order to represent key attributes of the U.S. food system 

that are obscured in the SNA. We use a matrix-reduction procedure that facilitates supply chain 

decomposition analysis of fossil fuel combustion and freshwater withdrawals (see section 2.2 in 

Rehkamp and Canning, 2018).

To facilitate a link between FEDS-EIO and the diet model (discussed above), FEDS-EIO uses food 

industry data to expand the number of consumer food commodities from the 22 covered in the 2007 

SNA to a total of 74 commodity groups, which are further broken out into at-home (e.g., grocery 
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stores) and away-from-home (e.g., restaurants) purchases (see appendix table 1 in Canning et al., 

2017). For example, in the SNA expenditure category ‘Processed Fruits and Vegetables’ are disaggregated into multiple expenditure categories based on product shipment data from the 2007 U.S. 

Economic Census. The individual food items from NHANES are mapped to the 74 expenditure 

groups based on composition. 

FEDS-EIO represents all U.S. annual production broken out into 344 industry aggregates (see 

appendix table 2 in Canning et al., 2017), and international imports are also categorized into these 

344 commodity groups. For each industry/commodity, annual 2007 production and imports are 

allocated to U.S. States. For production, energy use per unit of output is calculated using EIA’s State 

Energy Data System (SEDS), which reports State data on energy use for more than 10 primary fuel 

sources by type of end user (USDOE EIA, 2015). Water withdrawals per unit of output are calculated using the 2005 USGS data on water withdrawals in all U.S. counties broken out into surface 

water and groundwater sources (USDOI USGS, 2005). These calculations are aggregated up to U.S. 

totals to produce energy and waterflow multipliers for each of six energy commodities and two water 

sources. These multipliers and the other model features are used to translate gross output by industry 

linked to both the Baseline and Healthy American diet scenarios into total embodied energy- and 

water-use estimates by type of energy commodity and water source, across each supply chain stage.

Measuring Land Use and Farm Animal Inventories 

To account for land use in alternative diets in this report, we use the U.S. Foodprint Model (referred 

to hereafter as Foodprint). Foodprint is a biophysical simulation model that calculates the per capita 

land requirements of complete diets and the potential carrying capacity of the agricultural land of 

the conterminous United States (Peters et al, 2016). Starting with an estimate of dietary intake by 

food group, Foodprint determines the quantities of food and agricultural commodities required to 

supply a given amount of intake after accounting for losses and waste that occur in food preparation, 

distribution, and processing. The land requirement for producing each food commodity in the diet is 

calculated based on nationally representative estimates of crop yield, grazing land productivity, and 

livestock feed efficiencies. A land requirement for the complete diet is also calculated, which adjusts 

for the multi-use nature of certain crops (e.g., soybeans produce vegetable oil and high-protein livestock feed) and prevents double counting.

Two revisions were made to the Foodprint model for this analysis. First, the categories of food 

intake were expanded from the 25 foods and food groups in the original model to 65 retail food 

commodity categories (USDA-ARS, 2017). Second, the revised Foodprint model calculates the 

number of animals associated with the per capita intake in each diet scenario. Livestock inventories 

were estimated based on the amount of animal product (milk, eggs, or meat) required to support 

each scenario, with estimates of the number of animals associated with each unit of food output from 

Peters et al. (2014). In the original Foodprint model, the numbers of livestock needed to support a diet 

are implicitly accounted for in the feed requirements for producing animal-based foods (from Peters 

et al., 2014). The revised Foodprint model simply makes these calculations explicit.
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Measuring Air Use as a Repository for GHG Emissions 

Emission rates from fossil fuel combustion, measured with FEDS-EIO, vary across fuel source but 

also by activity. Rather than assuming a single emission rate for each fuel, we use specific emission 

rates for each activity, such as natural gas consumption in foodservice versus for packaging production in pulp paper and paperboard mills (Table S2 in Hitaj et al., 2019). We have activity-specific 

GHG emission rates for 70 percent of natural gas, petroleum, coal, and electricity consumption. For 

the remainder, we assume an industry average of carbon dioxide, methane, and nitrous oxide emission rate for each type of fuel (Table S3 in Hitaj et al., 2019). For GHG emissions produced in the 

power generation sector, we use the State-level emission rates provided in the EPA’s Emissions & 

Generation Resource Integrated Database (eGRID) for the year 2007. 

Hydrofluorocarbons (HFCs), a group of very potent GHGs, are used as coolants in refrigeration and 

air conditioning. While HFC emissions are occurring throughout the food system, we are only able 

to account for them in the transportation sector, where specific HFC emission rates are available 

(EPA, 2015); we are unable to tie HFC emissions from manufacturing and distribution to particular 

processes and food items, as would be necessary for our study. Accounting for HFC emissions from 

outside the transportation sector would therefore increase our estimate of total GHG emissions from 

the food sector.

Soil management nitrous oxide and methane emission factors (Table S4 in Hitaj et al., 2019) range 

from 340 kg CO2eq per acre of nitrous oxide emissions for soybeans to 3,508 kg CO2eq methane 

emissions per acre for rice production. Table S5 in Hitaj et al. shows the methane and nitrous oxide 

emission factors based on EPA (2017b) from enteric fermentation and manure management for 34 

different categories of livestock (beef and dairy cattle, broilers, layers, turkeys, and swine) at various 

stages in their production cycle.

Measuring Forest Product Use 

Whereas industrial uses for both energy commodities and water withdrawals are measured in physical units by major recurring Federal survey instruments, a data program for U.S. forest products 

does not exist at a similar level of detail. To overcome this data gap, our approach to measuring use 

by supply chain stage is to develop a value-added measure of forest product use simply represented 

by the monetized value of physical units for forest products. For this purpose, we employ the ERS 

Food Dollar model (Canning, 2011; Canning, Weersink, and Kelly, 2016). The Food Dollar model is 

exactly analogous to FEDS-EIO except for the units of measurement. For the present purposes, we 

base our estimates on the same 2007 SNA data described above for FEDS-EIO and documented in 

Canning et al. (2017). Because the Food Dollar model is a national model with no regional breakouts, we are able to use national-level data on 2007 U.S. timber production statistics (Howard and 

Jones, 2016) to make national-level conversions of hardwood equivalent volumes of forest product 

use by supply chain stage. Conversions are based on a strong assumption that all industrial users 

of forest products face the same hardwood-equivalent prices for the various products they use. It is 

likely that there are numerous exceptions to this assumption; however, we are aware of no compelling evidence that suggests this assumption introduces a systematic bias on our results reported in 

physical units. Further, this potential issue does not apply to our results reported in monetary units.