Dietary recommendations may be tied to increased greenhouse gas emissions

Dietary recommendations may be tied to increased greenhouse gas emissions
Data chart by: Martin Heller.

If Americans altered their menus to conform to federal dietary recommendations, emissions of heat-trapping greenhouse gases tied to agricultural production could increase significantly, according to a new study by University of Michigan researchers.

Martin Heller and Gregory Keoleian of U-M's Center for Sustainable Systems looked at the greenhouse gas emissions associated with the production of about 100 foods, as well as the potential effects of shifting Americans to a diet recommended by the U.S. Department of Agriculture.

They found that if Americans adopted the recommendations in USDA's "Dietary Guidelines for Americans, 2010," while keeping caloric intake constant, diet-related greenhouse gas emissions would increase 12 percent.

If Americans reduced their daily caloric intake to the recommended level of about 2,000 calories while shifting to a healthier diet, greenhouse gas emissions would decrease by only 1 percent, according to Heller and Keoleian.

A paper by Heller and Keoleian titled "Greenhouse gas emission estimates of U.S. dietary choices and food loss" is scheduled for online publication Sept. 5 in the Journal of Industrial Ecology.

"The take-home message is that health and environmental agendas are not aligned in the current ," Heller said.

The paper's findings are especially relevant now because the USDA Dietary Guidelines Advisory Committee is for the first time considering food sustainability within the context of dietary recommendations, he said.

In its 2010 , USDA recommends that Americans eat more fruits, vegetables, whole grains, fat-free and low-fat dairy products, and seafood. They should consume less salt, saturated fat, trans fat, cholesterol, added sugar and refined grains.

The guidelines don't explicitly state that Americans should eat less meat. However, an appendix to the report lists the recommended average daily intake amounts of various foods, including meat. The recommended amount of meat is significantly less than current consumption levels, which Heller and Keoleian estimated using the USDA's Loss Adjusted Food Availability dataset as a proxy for per capita food consumption in the United States.

While a drop in meat consumption would help cut diet-related greenhouse gas emissions, increased use of dairy products—and to a lesser extent seafood, fruits and vegetables—would have the opposite effect, increasing diet-related emissions, according to the U-M researchers.

In the United States in 2010, food production was responsible for about 8 percent of the nation's greenhouse gas emissions. In general, animal-based foods are responsible for more greenhouse gas emissions per pound than plant-based foods.

The production of both beef cattle and dairy cows is tied to especially high levels of greenhouse gas emissions.

For starters, cows don't efficiently convert plant-based feed into muscle or milk, so they must eat lots of feed. Growing that feed often involves the use of fertilizers and other substances manufactured through energy-intensive processes. And then there's the fuel used by farm equipment.

In addition, cows burp lots of methane, and their manure also releases this .

Greenhouse gas emissions associated with producing the U.S. diet are dominated by the meats category, according to Heller and Keoleian. While beef accounts for only 4 percent by weight of the food available, it contributes 36 percent of the associated , they conclude.

The U-M researchers found that a switch to diets that don't contain animal products would lead to the biggest reductions in this country's diet-related greenhouse emissions.

But Heller said he's not arguing that all Americans should go vegan, and he believes that animals need to be part of a sustainable agricultural system. However, reduced consumption would have both health and environmental benefits.

In their Journal of Industrial Ecology paper, Heller and Keoleian also looked at wasted food and how it contributes to U.S. emissions. They concluded that annual emissions tied to uneaten food are equivalent to adding 33 million passenger vehicles to the nation's roads.


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Citation: Dietary recommendations may be tied to increased greenhouse gas emissions (2014, September 5) retrieved 17 August 2019 from https://phys.org/news/2014-09-dietary-tied-greenhouse-gas-emissions.html
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Sep 05, 2014
Why would anyone follow a diet laid out by a federal agency, or state agency, or any entity that is making a broad-brush-stroke diet? The people that actually care enough to look at the source of their calories aren't going to be following the USDA recommended calorie intake anyways.

What about the source of their meats, vegetables, etc? Even the source of your dairy makes a difference (different cow feeds, regions, what dairy products you're using and the process that goes into making that product...). What if I grew my own vegetables instead of having a farmer using a large tractor harvest my vegetables? Goat milk vs. cow milk?

Bad research is bad.

Sep 05, 2014
Recommend away.
Just one more reason not to believe govt scientist/bureaucrats.

Sep 05, 2014
Think we're not out to control every aspect for your life? Think again. We'll have you wearing meters on your chest to measure and tax your CO2 emissions.

Sep 05, 2014
'cows don't efficiently convert plant-based feed into muscle or milk'
Really?
What other animal can turn grass into beef and milk?
"The microbes in the rumen digest cellulose and hemicellulose (i.e. fiber); produce a high quality protein, volatile fatty acids (VFA's), and B vitamins; and detoxify toxic compounds. One of the main by-products of fermentation are VFA's and these compounds are absorbed through the rumen wall and used as energy by the animal. Protein, which is digested in the rumen (digestible intake protein= DIP) is used to support microbial growth and functions. "
"The ruminant digestive system has allowed the production of meat and milk from forages, thus allowing us to use feeds and land not suited for other food production. "
http://fyi.uwex.e...-system/

Sep 05, 2014
The graph is misleading. And I suspect purposefully.

If you slice a pie into percentages, then each slice has an area comparable to the amount consumed. If you compare two such pies of unequal total amount, the pie areas (and not diameters) should represent their difference.

Doing things "to make the difference easier to notice" is not an acceptable excuse.

Sep 05, 2014
Until the elites start acting like there is an emergency, no more plane rides for Greenpeace execs, for instance, I'm going to continue with the only logical response,

"the polar bears will be fine" - Freeman Dyson

Because Dyson appears to be the only one making honest arguments. That and he is smarter, knows how to judge models and understands the maths better than perhaps any other single person on the planet.

Good day.

Sep 05, 2014
Someday we AND our cows will be legally required to wear filtered underwear.

Sep 06, 2014
'cows don't efficiently convert plant-based feed into muscle or milk'
Really?
What other animal can turn grass into beef and milk?
". . . thus allowing us to use feeds and land not suited for other food production. "

Muscle, or animal protein is not by any measure exclusively beef. Nor are we highly dependent on grass to feed our livestock.

Most beef, at least in the U.S. where a lot if it is consumed, is not raised in marginally useful land.

Sep 06, 2014
Until the elites start acting like there is an emergency, no more plane rides for Greenpeace execs, for instance, I'm going to continue with the only logical response,

"the polar bears will be fine" - Freeman Dyson

That all he ever wrote? Or is that all you've ever read? I'd be a bit reluctant quoting another, then in such a painfully reiterative manner (as you've done in many posts). Makes it seem as if I haven't an original thought myself to express.

As long as we're quoting, here's another:

"it is better to be wrong than to be vague."

BTW, I won't argue about disingenuous Greenpeace execs (or any other leaders for that matter) but to use their behavior as an excuse is childish.

Sep 06, 2014
is not raised in marginally useful land.

Doesn't change the fact that ruminant animals can thrive on fodder.
Most beef cows are grazed on marginal land. Quite efficient, contrary to the article.
Beef may be finished in feedlots with corn, but that does not produce the most healthy beef.
Dairy cattle benefit from high quality alfalfa. Alfalfa improves the quality of land.

Sep 06, 2014
This comment has been removed by a moderator.

Sep 07, 2014
Until the elites start acting like there is an emergency, no more plane rides for Greenpeace execs, for instance, I'm going to continue with the only logical response,

"the polar bears will be fine" - Freeman Dyson

That all he ever wrote?


don't be a pinhead.

Dyson on climate change.

http://youtu.be/-kSnd8t4ceQ

Sep 08, 2014
Soylent green anyone?

Sep 08, 2014
"Soylent green anyone?"
--------------------------------

Thanks for bringing that up. That was when corporations took over the government, and killed the environment, until even the oceans were dying in the pollution.

Did you not learn the lesson? Do you not see it coming?

Sep 08, 2014
"Soylent green anyone?"
--------------------------------

Thanks for bringing that up. That was when corporations took over the government, and killed the environment, until even the oceans were dying in the pollution.

Did you not learn the lesson? Do you not see it coming?

It's movie.

"corporations took over the government"
When a govt won't protect private property rights, it doesn't matter who controls the govt.

Sep 08, 2014
It was supreme property rights and absolute selfishness that got us to Soylent Green, the takeover of government by Big Business, which killed the Earth, as it is doing right now.

I suggest you get some environmental learnin', and see what your prehistoric attitudes mean in the modern world.

Sep 08, 2014
takeover of government by Big Business

That is socialism.
Any company that want's to stay in business needs customers and won't kill their customers.
Crony 'capitalists' use the govt to impose an excessive regulatory burden (plundering private property) to force competitors out of business.
Why does the US Chamber of Commerce support amnesty for millions of illegal aliens when there are tens of millions of US citizens unemployed and on welfare?

Sep 08, 2014
I want you to pay me for your freedom, since you did not earn it yourself. Money seems to be the only thing in your life, so let's talk money.

Pay up.

Did you vote for Bush? You owe us $4,000,000,000,000 for your Bush Wars.

Sep 08, 2014
I want you to pay me for your freedom

Molon labe.

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