If consumers want to reduce greenhouse gas emissions, they can start with what they put on their dinner plate.

Not consuming red meat and dairy products one day a week reduces the same amount of greenhouse gas emissions as driving 1,000 fewer miles per year, according to two Carnegie Mellon researchers.

Eliminating this food source entirely from a diet reduces greenhouse gas emissions equivalent to 8,000 miles per year.

A 2006 United Nations report accounted 18 percent of worldwide greenhouse emissions to livestock.

“I think the situation in North America is not as dire as the situation around the world,” said Larry Newton, a dairy and science professor at the Tifton campus.

The percentage encompasses the complete cycle, including transportation and production of livestock, Newton said.

The report calculated the greenhouse gas emissions from transporting grains to feed livestock and transporting animal products from farmer to retailer. Other countries convert forests into land for feed production, but the United States does not have a high rate of deforestation, he said.

In fact, North America’s agricultural land has decreased by four percent, he said.

“We’re using less land area because the increased efficiency of land and animal production,” said Kelly Zering, professor of agriculture and resource economics at North Carolina State University, in a phone interview.

Manure from livestock contains methane gas and nitrous oxide, both of which are greenhouse gases. But, generally speaking, livestock has few effects on greenhouse gas emissions, Zering said.

“Cattle aren’t producing as much methane as they were 50 years ago,” Newton said.

Both professors are working on a report that calculates the environmental effects of meat consumption in North America.

The research from the two Carnegie Mellon concludes that eliminating red meat from a diet once a week has a greater effect on the environment than eating only locally grown food. The reason is that greenhouse gas emissions are much greater during food production than food transportation.

Thus, the paper suggests “that dietary shift can be a more effective means of lowering an average household’s food-related climate footprint than ‘buying local.’”

The Environmental Science & Technology journal published the findings, for which Christopher L. Weber and H. Scott Matthews won the award for “Best Paper on Environmental Policy of 2008.”

Some consumers choose to eat a vegetable-based diet for health reasons. Vegetarians have a lower risk of heart disease, diabetes and certain cancers, said Angela Ruhlen, a nutrition coordinator at the University Health Center, in an e-mail Friday.

“Most vegetarian diets, if planned correctly, are sufficient in all necessary nutrients,” she said.

Veganism is a type of vegetarianism that avoids animal foods and any products made from or tested on animals. The concern with this diet is it lacks vitamin B-12, which can only be found in animal products, Ruhlen said.

“Therefore, I recommend that strict vegans take a supplement that contains vitamin B-12 to avoid deficiency,” he said.

A University student became a vegetarian two years ago after learning about mad cow disease.

“I saw that and thought that was horrible and looked online and saw what it was like in slaughter houses and factory farms,” said Megan Brunning, a senior from Lilburn. “Then it just clicked that I didn’t agree with eating animals and especially not torturing them while they’re alive.”

In June, she became a vegan because she didn’t agree with the conditions for hens laying eggs.

“My main reason is animal welfare. Once I became vegan, I learned that it’s better for the environment, too.”