September 2008 Issue

The Low-Carbon Diet: A Protection Plan for the Planet
By Juliann Schaeffer
Today’s Dietitian
Vol. 10 No. 9 P. 42

Opting for a grilled chicken breast over a juicy burger. Snacking on seasonal tomatoes from a local produce stand. Adding spinach, not cheese, to your lunchtime sandwich. These actions surely sound healthy, but environmental advocates and recent research suggest that they could also help save the planet, as well as consumers’ waistlines.

Although many Americans associate climate change with fuel-guzzling, carbon dioxide-emitting automobiles, it turns out that food is an even bigger contributor to the warming trend, especially the beef and dairy industries. As environmental awareness escalates, low-carbon diets are starting to gain traction, and consumers are fighting back against greenhouse gases—with their forks.

“The modern food system, particularly in the United States, contributes abundant amounts of three of the six principal greenhouse gases [GHG] that create the ‘greenhouse effect,’” says Helene York, director of the Bon Appétit Management Company Foundation. “These gases are carbon dioxide from fossil fuels burned during transportation and processing of food products, methane emitted by ruminant animals and also by food waste decomposing in landfills, and nitrous oxide due to overuse of nitrogen-based fertilizers and other agricultural practices.”

In fact, about 22% of GHG emissions in the United States come from the food sector, explains Marissa Cloutier, MS, RD, a biology and nutrition instructor at the University of Hartford in Connecticut. “The beef industry is the biggest contributor, with dairy running in second,” she says. “Burning fossil fuels produces emissions of particles that thicken the blanket of our atmosphere, producing a tighter ceiling that traps in solar rays. Hence, the term ‘greenhouse,’ as this thicker atmospheric layer produces a condition that is exhibited in greenhouses: a warmer climate.”

Cloutier, who was recently accepted into Harvard University to pursue her doctorate in public health nutrition, notes that,  unfortunately, public perception about climate change usually doesn’t stretch beyond consumers’ car seats. “Modern America is built on a sea of petroleum, with our food system included,” she says. “Most of this is unseen by the average consumer. We are only intimate with the petroleum going into our cars at the pump, not into our food.”

“I think the reason why the public generally associates carbon emissions with fuel instead of food is because the problem of climate change has been defined in the United States in terms of carbon dioxide, not in terms of the array of greenhouse gases, including methane and nitrous oxide, which are far more potent,” says York.

She believes part of this problem stems from the United States’ straying from its agricultural society roots. “And we know little about where our food comes from or how it is produced, so we don’t think about food as anything but fuel for our bodies. Only now are people starting to ask questions about how food gets on our plates.”

Beef No More
Bon Appétit Management Company, an on-site restaurant company that offers foodservice management to corporations and universities, is hoping to change consumers’ perception while curbing its own bad environmental habits. On Earth Day last year, the company launched a national campaign to not only reduce its own GHG emissions but also help its guests do the same. With 400 cafés nationwide, Bon Appétit is increasing the environmental awareness of both chefs and diners by creating its version of the low-carbon diet, which involves buying foods that have a lower environmental impact on our planet.

Parked at the peak of the low-carbon diet program is decreasing beef and dairy consumption by 25%, if not eliminating it. “If you’re trying to eat a low-carbon diet, focusing on reducing meat and dairy consumption would have a significant impact,” York says. “Meat and dairy are especially high in carbon because ruminants (cows, sheep, and goats) naturally emit methane, a greenhouse gas 23 times more potent than carbon dioxide. In addition, North American, Japanese, and European data are clear that emissions associated with large animal products are high.”

York notes that the high emission content in beef and dairy comes from several factors, in addition to their methane emissions, including the energy inputs associated with the following:

• the production of feed for animals;

• the length of time it takes to grow animals to maturity compared with plants;

• the feeding of animals; and

• the animals’ weight, which is also a factor in transport emissions.

When it comes to high-carbon foods, beef seems to be the biggest offender. “The [most powerful step we can take] to ease the environmental crisis at hand is to cut our beef consumption,” says Cloutier, who recommends as drastic a cut as people can manage. “But, certainly, any reduction is better than nothing at all. Even if for just one day or one meal, a shift from beef to poultry will make a difference.”

Cloutier says there’s definitely room for a cutback on beef consumption in the nation, as the typical American diet consists of a high percentage of protein from cows—and it isn’t helping the health of people or the planet. She advises dietitians to recommend that clients reduce their beef intake, just as they’ve recommended cutting saturated fat for heart disease prevention and treatment: first cut back on portions, then on the number of times consumed per week, then ease out such foods as much as possible while substituting other foods, such as chicken and poultry.

“Sticking to the Dietary Guidelines for Americans or that of the American Heart Association is a good place to start as a model diet for the environment, although the focus here is from percent fat of cut to beef in general,” she says. “I would recommend even further cuts in meat from ruminants or that of animal protein (again, considering the impact of the dairy industry as well) from these guidelines as an ultimate goal, but this is a good place to start.”

While carbon dioxide seems to steal the headlines pertaining to climate change and carbon footprints, Liz Marr, MS, RD, emphasizes that other potent GHG are also at work on the atmosphere. “Methane and nitrous oxide are also greenhouse gases yet are often not included in calculating a diet designed to reduce the ‘carbon’ footprint. Recent research included several different GHG, including these, and found that meat and dairy production had a much higher impact on greenhouse gases than did the contribution of food miles,” says Marr, who heads up Liz Marr and Associates, LLC in Longmont, Colo., an independent, strategic communications consultancy specializing in food, nutrition, health, wellness, and sustainability.

As for food miles, a rough measure of how far food travels between its production and the final consumer, new research suggests that while they are a factor, they’re not always the best indicator of the GHG impact of foods. According to Weber and Matthews in the recent article “Food-Miles and the Relative Climate Impacts of Food Choices in the United States” in Environmental Science & Technology, “Transportation as a whole represents only 11% of GHG emissions and final delivery from producer to retail contributes only 4%.”1

Although some environmental activists may tout local produce as the key to combating climate change, Weber and Matthews say minimizing red meat consumption is the true solution. “Shifting less than one day per week’s worth of calories from red meat and dairy products to chicken, fish, eggs, or a vegetable-based diet achieves more GHG reduction than buying all locally sourced food,” the authors wrote.

For clients wide-eyed at the thought of saying good-bye to their rib-eye, Marr says their takeaway message should be that dietary changes need not be extreme to make an environmental impact. “As with making dietary changes for health, small steps add up and are more likely to be sustainable behavior changes vs. a complete dietary overhaul,” she says.

Seasonal and Local
For those simply not open to decreasing beef consumption, there are other, albeit less effective, options. Bon Appétit’s low-carbon diet recommends that consumers use seasonal, local produce as a first preference, picking up tropical fruits only as “special occasion” ingredients.

Because a large share of food exports include fruits and vegetables shipped between the northern and southern hemispheres in order to take advantage of alternating winters, the food miles can add up fast. Conversely, local foods generally travel less food miles, and seasonal produce is more environmentally friendly because it’s not grown in energy-intensive greenhouses. “Seasonal is key. Buying seasonal means it was grown in respect to Mother Nature’s systems of production,” says Cloutier.

Examples of so-called high-carbon foods are out-of-season perishable food items, such as berries in winter or “fresh” fish. “Also, avoid produce grown in hothouses during winter (unless the hothouses are powered by renewable energy). This practice is extremely carbon intensive. That’s why our message is buy locally and seasonally,” says Katherine Kwon, MS, RD, communications project manager at Bon Appétit Management Company.

As Cloutier reiterates, locally grown foods are only less energy intensive when they are seasonal because “locally grown in the Northeast in January most likely means grown in an energy-intensive greenhouse.”

So how do you figure out foods’ path to your palm? The easiest way to tell where foods are coming from is to buy directly from the source: local farmers. And farmers’ markets could be the easiest recommendation for consumers looking to eat for a healthier planet. “Purchasing fruits and vegetables from farmers’ markets and produce stands is definitely a great way to eat locally and seasonally,” says Kwon. “At Bon Appétit Management Company, our chefs have been supporting local farmers and communities as part of our companywide Farm to Fork initiative, which was established nine years ago. Currently, 30% of the food served in Bon Appétit cafés are from within a 150-mile radius of the café.”

Kwon adds that subscribing to a community-supported agriculture (CSA) produce box, if it’s available in your area, is another way to enjoy fresh produce that’s in season. “In addition to being low carbon, local and seasonal fruits and vegetables tend to be more flavorful than produce shipped from far away,” she says of an added benefit to shopping local.

At larger, more common grocery stores, Kwon says it’s still possible to identify where some food items originated with country-of-origin labeling, but it’s almost impossible to ascertain how much energy went into an item’s production, processing, and transportation while staring at it in the store. Because of the complexity of the U.S. food industry, it may be easier for clients to frequent farmers’ markets when trying to decrease their environmental impact with what they’re eating.

The many advantages of farmers’ markets should make them an easy recommendation for dietitians, as shopping local can open up a plethora of possibilities due to the many available food varieties. “I think that eating seasonally actually helps diversify one’s diet,” says Kwon of one benefit. “Although we Americans have a vast selection of produce available to us year-round, many people tend to purchase and prepare foods that are most familiar to them. My first CSA box was such an educational experience as I was introduced to green garlic and fennel, items I just passed by in the grocery store.”

Cloutier says supporting local farmers also leads to a larger crop selection: “By supporting the local farmers, you are supporting a return to increased biodiversity, something that is absolutely essential for sustainability. We once had many more varieties of tomatoes, apples, etc. What we see in the standard supermarket is a very small percentage of the varieties that actually exist in natural systems. Buying locally and seasonally will expand our selection options.”

Marr lists more compelling reasons why she believes backing local agriculture benefits both buyers and sellers, including the following:

• It supports the local economy and agricultural land use.

• It promotes regional cuisine and crop diversity (eg, preservation of heirloom varieties).

• It connects consumers, including children, with food production.

• It improves access to nutritious foods.

But make clients aware that buying local is no equal switch for decreasing beef intake. As Weber and Matthews wrote, “…for the average American household, ‘buying local’ could achieve, at maximum, around a 4-5% reduction in GHG emissions due to large sources of both CO2 and non-CO2 emissions in the production of food. Shifting less than 1 day per week’s (i.e., 1/7 of total calories) consumption of red meat and/or dairy to other protein sources or a vegetable-based diet could have the same climate impact as buying all household food from local providers.”

A Throwaway Nation
Given the option when dining out, which is better: throwing away the leftovers or taking it home in a nonbiodegradable container? According to the British organization Waste & Resources Action Programme (WRAP), people are more “concerned about throwing away plastic and other waste perceived of as nonbiodegradable but less so about biodegradable waste which is not generally regarded as an environmental problem.”

A 2007 WRAP survey revealed that 40% of people thought throwing food away was not an issue because it’s biodegradable and natural, with three quarters of people thinking packaging was more of a problem than food waste. However, in a perhaps stunning statistic, WRAP wrote in a food waste analysis that “we could make carbon savings equivalent to taking an estimated 1 in 5 cars off the road if we avoided throwing away all the food that we could have eaten.”

Kwon says food waste is one of the most important yet most forgotten pieces of the food and climate change puzzle. “Food waste is a tremendous contributor of greenhouse gases, specifically methane,” says Kwon. “It takes an enormous amount of energy to produce food, and all that embodied energy is wasted if it’s thrown out. When sent to landfills, food waste breaks down and emits methane gas. ... As part of the low-carbon diet, we recommend that people buy and prepare only the food they expect to eat and also to save leftovers if they don’t finish all their food in one sitting.”

Cloutier says food waste is unfortunately customary of American society. “[The United States] is definitely a throwaway society,” she says. “We need to be more conscious of our portion sizes—both the portions we purchase and the portions we prepare that won’t be eaten. Composting is great to help with this.”

Although consumers can control portion sizes and be more aware of using perishables, Marr says some food waste is simply out of consumers’ control. “Part of food waste is at the retail and wholesale level, when products don’t move fast enough and reach expiration date or spoil before selling,” she says. “However, consumers can do their part by buying only what they think they’ll consume or be able to prepare and store. With the rising price of food and the downturn in the economy, many people are likely planning their food purchases more carefully; that may help reduce home waste.”

Introducing yourself or clients to composting could also do a world of good. “Some communities are starting curbside composting, and people have the option to do backyard/home composting. Such efforts reduce the amount of organic waste going into landfills. Plus, your backyard compost helps enrich your soil,” says Marr.

Commonsense Tactics
When educating others about the environmental impact of their dietary choices, Cloutier says keep it simple. “For the average consumer, use common sense: the more processed a food item, the more energy intensive. Go for foods with minimal ingredients and as close to the original as possible—that is, apples instead of apple fruit roll ups. Sound familiar? It’s what dietitians have been preaching for public health for quite some time. It’s all about going back to the basics for advancement in the food sector.”

Cloutier calls on all dietitians to place the tools to combat climate change into clients’ hands. “It is really in the hands of us dietitians and all healthcare professionals to take a role in climate change mitigation. We absolutely must support measures to curb the crisis at hand. All elements of climate change mitigation—from the energy and transportation sector to agriculture—have a link with public health.”

While there are still many outstanding questions about the effects climate change will have on the world and food’s role in it, Kwon says education and awareness are essential. “Increasing awareness about the effects of our food choices on the environment, as well as our surrounding communities and our personal health, is extremely important, and that’s precisely the goal of Bon Appétit’s Circle of Responsibility program,” she says. “Although we do know a lot more than we did 10 years ago, there are still many unknowns out there about the far-reaching effects of the food system. Asking these questions is definitely a step in the right direction.”

Still, reducing or eliminating beef intake or buying seasonally is only one step on the long road to eating for environmental sustainability. “Greenhouse gases are only one environmental consideration related to food. Others include growing foods in a way that supports biodiversity, protects existing natural resources (such as forests, wildlife, and water), and minimizes fertilizer and water inputs (for example, growing foods appropriate to local climates),” advises Marr. “Choosing to eat to sustain the environment includes many considerations. Focusing only on GHG in terms of environmental impact is like only focusing on vitamin C when it comes to nutrition.”

— Juliann Schaeffer is an editorial assistant at Today’s Dietitian.

1. Weber CL, Matthews HS. Food-miles and the relative climate impacts of food choices in the United States. Environ Sci Technol. 2008;42(10):3508-3513.


A New Kind of Eating Utensil
Bon Appétit Management Company’s Low Carbon Diet Calculator is a fun and interactive Web-based tool that reveals the relative carbon impacts of specific foods and is based on best-available science. By dragging and dropping menu items, ingredients, or suggested meals onto the virtual skillet, users can see which of their food choices are contributing more to climate change. For more information, visit