Sheila's Nutrition Digest Vol 14 - Can your eating habits affect global warming?
By:  Sheila Kealey   (2007/01/12)

The weather this winter has heightened our awareness about global warming.  With little snow, compromised recreation and training, and the cancellation of many World Cup cross country and downhill events, winter athletes are taking notice, worried about their sport and the future of our environment. Olympic medalist Sara Renner and her partner double World Cup winner Thomas Grandi have publicly stated that they are going "carbon neutral," reducing their impact on the environment and offsetting the greenhouse gas emissions they produce. There are many things we can do to reduce the amount of greenhouse gases that we put into the atmosphere.

Many people aren't aware that their food habits can also have an impact on global warming. In fact, a great deal of energy goes into growing, harvesting, and preparing the foods we eat.

Here are some things you can consider to reduce the impact of your dietary habits on the environment.

1. Strive for a plant-based diet

Producing food from animals takes about 10 times as much fossil fuel compared to plant food production. Also, animals emit methane, a greenhouse gas; in fact, some experts estimate the methane from animal agriculture is responsible for 15% of human-induced global warming.

At the extreme, a vegan diet (no animal products) contributes 1.5 fewer tonnes/yr of CO2 to the atmosphere than the typical North American diet, according to a recent study conducted by the University of Chicago. This research suggests that the food people eat is just as important as what kind of cars they drive when it comes to creating greenhouse-gas emissions.

Further, a recent United Nations report notes that a typical meat-based diet adds significantly to pollution, water scarcity, land degradation, and climate change. The report states that animal farming presents a "major threat to the environment" with such "deep and wide-ranging" impacts that it should rank as a leading focus for environmental policy.

Although eliminating animal products is unrealistic for most, replacing some of your animal foods with plant-based foods is something everyone can do. For example, increase the beans and decrease the meat next time you make chili. This is good for your health too, as described in the New American Plate, a disease-fighting way of eating that proposes that 2/3 of your plate (or more) consist of vegetables, fruits, whole grains, and beans, and 1/3 of your plate (or less) consist of animal protein.

Curious about the environmental burden of the animal products you eat? Check out the Eating Green Calculator.

2. Buy Seasonal and Local

Asparagus in January? This would have been a rarity for many Canadians 20 years ago, but today our supermarkets carry foods from all over the world. While this variety has many benefits, it's important to consider the amount of fossil fuel used to transport food. Some estimates suggest that on average, food travels about 2500 km before it reaches your table, while other reports reveal that making a typical meal with supermarket ingredients takes four to 17 times more petroleum consumption (in transport) than the same meal made using local ingredients.

Support your local growers and buy what's in season. Look for local foods at farmers markets, or through community supported agriculture (CSA).You will have to compromise during our Canadian winters, but do try to supplement produce shipped from Mexico or California in refrigerated trucks with something that hasn't traveled so far (for example, you can still get cabbage, apples, squash, root vegetables, etc.). Airplane transport (e.g., asparagus from Peru, apples from New Zealand) has an even greater environmental toll, so try to limit these foods.

Buying 25% more of your food locally is estimated to save at least 1/5 tonne of greenhouse gases.

3. Buy Organic

Organic foods may help reduce climate change because they use alternatives to nitrogen-based and petroleum-based fertilizers. Also, organic farming practices may help limit CO2 emissions from soil. Nitrogen-based fertilizers are a prime contributor of nitrous oxide (N20), a greenhouse gas. One 22-year farming trial study estimated that for certain crops, organic farming used an average of 30 percent less fossil energy compared to conventional farming.

4. Limit your waste

Nonrecycled garbage ends up in a landfill, which, in addition to several other environmental problems, generates methane. It's estimated that about 20 per cent of Canada's share of global warming gases comes from landfill sites.

Paper or plastic? There are problems with both, so the best option is to bring your own reusable bag to the grocery store.

Packing a lunch? Single use plastic bags, aluminum foil, and single-serve items with disposable packaging are convenient, but at a heavy environmental cost. Some reports estimate that a school-age child using a disposable lunch generates 67 pounds of waste per school year.

Strive to pack food items in reusable containers. The Waste Free Lunch site has great ideas.

Also, always try to buy unpackaged or minimally packaged foods.

5. Food Storage and Preparation

The average home causes more air pollution than the average car, because power plants that burn fossil fuels produce the energy for most of our electric products. Food storage and preparation uses a significant amount of energy. In fact, cooking alone can account for 10 percent of an average home's consumption of electricity, according to the Office of Energy Efficiency at Natural Resources Canada. Here's how you can reduce the energy used for food storage and preparation:

- Select the right pan or appliance (oversized pans waste energy)

- Keep lids on pans when you cook (lidless pans can require up to three times more energy)

- Use energy-efficient small appliances. Slow cookers save energy preparing foods that require long cooking times; pressure cookers are very efficient since they cook quickly.

- Use microwave ovens when possible. They use less energy, require shorter cooking times, and don't heat up your kitchen in the summer.

-  Use a toaster oven instead of your conventional oven whenever possible

- Your refrigerator could be the biggest power consumer in your home. Consider an energy star model if you don't have one already.

Further Reading:

The Omnivore's Dilemma by Michael Pollan.

Six Arguments for a Greener Diet: How a More Plant-Based Diet Could Save Your Health and the Environment by Michael F. Jacobson.