Chronicle Online e-News
Diet for small planet may be most efficient if it includes dairy and
a little meat, Cornell researchers report
http://www.news.cornell.edu/stories/Oct07/diets.ag.f
ootprint.sl.html
Oct. 4, 2007
By Susan Lang
ssl4@cornell.edu
A low-fat vegetarian diet is very efficient in terms of how much land
is needed to support it. But adding some dairy products and a limited
amount of meat may actually increase this efficiency, Cornell
researchers suggest.
This deduction stems from the findings of their new study, which
concludes that if everyone in New York state followed a low-fat
vegetarian diet, the state could directly support almost 50 percent
more people, or about 32 percent of its population, agriculturally.
With today's high-meat, high-dairy diet, the state is able to support
directly only 22 percent of its population, say the researchers.
The study, published in the journal Renewable Agriculture and Food
Systems, is the first to examine the land requirements of complete
diets. The researchers compared 42 diets with the same number of
calories and a core of grains, fruits, vegetables and dairy products
(using only foods that can be produced in New York state), but with
varying amounts of meat (from none to 13.4 ounces daily) and fat
(from 20 to 45 percent of calories) to determine each diet's
"agricultural land footprint."
They found a fivefold difference between the two extremes.
"A person following a low-fat vegetarian diet, for example, will need
less than half (0.44) an acre per person per year to produce their
food," said Christian Peters, M.S. '02, Ph.D. '07, a Cornell
postdoctoral associate in crop and soil sciences and lead author of
the research. "A high-fat diet with a lot of meat, on the other hand,
needs 2.11 acres."
"Surprisingly, however, a vegetarian diet is not necessarily the most
efficient in terms of land use," said Peters.
The reason is that fruits, vegetables and grains must be grown on
high-quality cropland, he explained. Meat and dairy products from
ruminant animals are supported by lower quality, but more widely
available, land that can support pasture and hay. A large pool of
such land is available in New York state because for sustainable use,
most farmland requires a crop rotation with such perennial crops as
pasture and hay.
Thus, although vegetarian diets in New York state may require less
land per person, they use more high-valued land. "It appears that
while meat increases land-use requirements, diets including modest
amounts of meat can feed more people than some higher fat vegetarian
diets," said Peters.
"The key to conserving land and other resources with our diets is to
limit the amount of meat we eat and for farmers to rely more on
grazing and forages to feed their livestock," said Jennifer Wilkins,
senior extension associate in nutritional sciences who specializes in
the connection between local food systems and health and co-authored
the study with Gary Fick, Cornell professor of crop and soil
sciences. "Consumers need to be aware that foods differ not only in
their nutrient content but in the amount of resources required to
produce, process, package and transport them."
According to the U.S. Department of Agriculture, the average American
ate approximately 5.8 ounces of meat and eggs a day in 2005.
"In order to reach the efficiency in land use of moderate-fat,
vegetarian diets, our study suggests that New Yorkers would need to
limit their annual meat and egg intake to about 2 cooked ounces a
day," Peters said.
The research was supported in part by the National Research
Initiative of the USDA Cooperative State Research, Education and
Extension Service.
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Chris Peters honored for foodshed work
Chris Peters, the lead author of the study on New York's agricultural
footprint, has been honored for related work on local "foodsheds," as
well as his teaching and outreach, with the 2007 Gerald O. Mott
Scholarship for Meritorious Graduate Students in Crop Science. The
award will be presented Nov. 6 at the American Society of Agronomy,
Crops Science Society of America and Soils Science Society of
America's International annual meetings in New Orleans.
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