Quantifying Environmental Impacts of Dietary Recommendations

Quantifying Environmental Impacts of Diets

Global Food

System

Dietary Guidelines

Food Subsidy

Program

Crop Uses

Nature, Foley et al. 2011

36% Calorie production used for animal

feed

Million calories per hectare

food

feed

biofuels

Calories

delivered to

people

Calories available in food system

Calories “lost”

Maize

~10 %

conversion

efficiency

Cassidyet al.Submitted


59% Calories produced become food


67% Calorie production used for animal

feed


34% Calories produced become food

Source: FAO Food Balance Sheets

What’s recommended?

~0.7 grams / kilogram

90 kilogram person (200 lbs)

63 grams per day = 23 kilograms per year

Dietary Reference Intakes: The Essential Guide to

Nutrient Requirements:

http://www.nap.edu/catalog/11537.html


23 kg per person yr-

1

Hyperpenelopereddit

Land Requirements

Tons per grid-cellTons of maize

Vegetal vs. Animal

A.F. Bouwman et al. / Agricultural Systems 84 (2005) 121–153

Square meters per 100 grams produced

Land Requirements

Water footprints

Hoekstra et al, Water Footprints

Hoekstra, A. Y. &Mekonnen, M. M. (2012) The water footprint of humanity.

Proceedings of the National Academy of Sciences 109, 3232-3237

Greenhouse gas emissions

Agriculture accounts for 19%–29% of total global

anthropogenic GHG emissions.

Of this, the production stage contributes 80%–86% of

emissions at the global level

Vermeulen, S., Campbell, B. M., & Ingram, J. S. (2012). Climate Change and Food

Systems. Annual Review of Environment and Resources, 37(1).


Kg Nitrogen application per ton maize produced

1% Nitrogen applied becomes N2O (according to IPCC)Nitrous Oxides (N2O) = 310x Global Warming potential CO2


Enteric

Fermentation

Methane (CH4) = 21x Global Warming potential of CO2


1992 2008Image: NASA


Grams GHGs per100 grams produced

Source: FAO STAT

Meat = 15%

30%

14%

14%

13%

7%

5%

6%

4%

Meat = 44%

26%

44%

29%

Meat = 47%

Meat = 64%

56%

How will guidelines impact environmental footprints?


23 kg per person yr-

1

U.S. Guidelines diet shift

123 kg per

person per year

30 kg

per person

per year

93kgs of fruits,

veggies, pulses

and cereals

(75% reduction meat)

Diet shifts

Average US diet, 2008 75% reduction meat 75% reduction meat,

no beef

Diet shifts

Average US diet, 2008 2008 meat

consumptio

n, no beef

75% reduction meat 75% reduction meat,

no beef

Nutrition Guidance in Reality

Discovery’s Vitality

Healthy Food Benefit

Data

Purchase weights of foods

>240,000 participants

Sturm et al. 2013

• An increase in the ratio of fruit and vegetables to total food

expenditure by 5.7% - 8.5% (dependent on subsidy);

• and a decrease in the ratio of less desirable to total food

expenditure by 5.6% - 7.2%

Healthy Food Purchases

Preliminary Results of Purchase Weights


• 16% decrease in the proportion of beef purchase weight;

• 10% decrease in the proportion of pork purchase weight;

• 5.4% increase in proportional vegetable purchases;

• 8.8% increase in proportional fruit purchase weight;

• ~8 - 13% decrease in land requirements

• ~7 - 12% decrease in water footprint

• ~8 - 10% decrease in greenhouse gas emissions

Healthy Food Purchases


EarthStat.org

Thanks!

@Cassidy_Emily (Twitter)

Technology

Quantifying Environmental Impacts of Dietary Recommendations