The secret to a low carbon diet

Photo: istockphoto.com/fotogeek4
New Canadian research shows that eating local isn’t the only important ingredient.

In recent years, many environmentalists have heralded local food as the greenest way to eat. But new research, including some from Canadian researchers, is showing that that’s not the whole story.

Nathan Pelletier, a researcher at Dalhousie University’s School for Resource and Environmental Studies, in Halifax, has found that the real recipe for a low carbon diet is to consider not just how far food is transported but also how it is produced. When he compared various protein sources such as tilapia, salmon, poultry, pork and beef in terms of the greenhouse gases they released, he found that the worst offender mooed. But the real surprise was why.

Pelletier’s research, presented mid-February at the annual meeting of the American Association for the Advancement of Science in Chicago, showed that for all these protein sources but beef, the main greenhouse gas contribution came from the production of the feedstock. In contrast, 60 percent of the greenhouse gas emissions associated with beef were related to either methane production (cow burps, or worse) or nitrogen from the treatment of manure.

He then compared the amount of feed required for each animal, discovering that in fish only 1 to 2 kg of feed is required per kilogram of weight gain. In beef, it was between10 and 30 kg. That means cattle carry the heaviest burden of conventional agriculture’s emissions.

Pelletier also put beef in context in the North American grocery store, showing that it represents a third of the North American protein market, along with pork and poultry. Yet, it is responsible for more than three quarters of livestock’s emissions in North America.

What’s more, that number is expected to grow as developing countries adopt North America’s taste for beef. Experts say a good yearly consumption of animal protein by a healthy person is 53 kg, while per capita the average North American currently consumes 90 kg per year and international food models expect it to grow to 103 kg per year by 2050.

However, there is hope. If North Americans choose to split their overall protein consumption between beans and beef, they would actually see a 70 percent drop in meat-related greenhouse gas emissions. And, if we ate only beans (97 percent of soybeans currently go to animals, which is enough to feed the entire developed world) the reduction would be more than 95 percent, says Pelletier.

“Given the critical importance that the livestock sector and our meat consumption choices have on anthropogenic [human-induced] greenhouse gas emissions now and into the future, this is an issue that demands critical attention,” said Pelletier. “And in terms of targeted personal and public policy interventions to reduce the food system climate impact, choosing climate friendly protein supply chains truly is a low hanging fruit, and I believe it is time we bring this awareness to the table.”

Going Beyond Food Miles


Ulf Sonesson, a scientist with the Swedish Institute for Food and Biotechnology, also advises against just focusing on food miles or local foods, since it represents a very small part of the carbon picture.

“[Food] is a complex system,” says Sonesson. “In order to make some informed decisions about how food products affect climate change, you have to look at the whole picture, and looking at one part doesn’t make much sense.”

To help consumers choose wisely at the grocery store, a new European food standard that goes beyond food miles was released in Fall 2008, and some manufacturers have already signed on.

The PAS 2050 Standard was developed by the Carbon Trust, a UK-based environmental group, that is hoping the new labeling standard will “help companies measure, reduce and communicate the lifecycle greenhouse gas emissions of products…” and serve to help businesses and consumers make wiser purchasing choices.

Changing the World One Cheeseburger at a Time

In addition to the Carbon Trust’s new food standard, private companies are getting in on the act. Bon Appétit Management Company rolled out a low carbon diet program to more than 400 of its cafeterias and cafés, many at universities and corporate headquarters, across the United States in 2007.

The food company emphasized quality local food within 150 miles of its onsite restaurants for several years, even changing their menus in the winter when some fresh vegetables were unavailable locally. But it took its commitment to the environment to the next level by pledging to reduce beef and cheese use by 25 percent in two years.

That two-year period expires in April 2009, and Helene York, the mastermind behind Bon Appétit’s low carbon program, says the company is likely to meet and exceed its target for beef reduction. In the program’s first year alone, it dropped by 23 percent. However, York said that vegetarianism and lack of alternatives have made it hard to reduce cheese, even though it will probably be down around 15 percent.

York emphasizes that much of the last two years has been spent educating suppliers, chefs, food-service employees, and customers about what it means to eat a low carbon diet. For chefs, that has meant educating them that frozen fish has the same taste qualities as fresh fish, while for its food-service personnel, it has meant learning how to show kindness to customers without giving away so much food that it gets wasted. And, then there are the consumer distractions such as disposable containers.

“There is so much noise about the whole idea about disposable packaging,” says York. “The carbon emissions equivalent in grams for one clamshell—the container you put a cheese burger in—is worth about 50 grams of emissions in the total process. The cheeseburger is about 2000 [grams]. It’s not the container that matters, it’s what’s inside.”

To help consumers find low-carbon foods, the Bon Appétit group created the Low Carbon Diet Calculator, a simple online program where people can evaluate the carbon emissions associated with eating out. According to York, half a billion meals are eaten out each day in the U.S., so before you head to your local eatery for a snack, check out your best low-carbon meal options.