Let Us Consider Lettuce--Sustainably
Growing your own lettuce can do more for our planet than giving up bacon.
In 2015, Carnegie Mellon University professor Paul Fischbeck made headlines by saying, “Eating lettuce is over three times worse in greenhouse gas emissions than eating bacon.” Of course, the real story is less provocative and more complicated, but the study that Professor Fischbeck was summarizing did show that how we grow our salads (particularly, how we grow lettuce, eggplant, celery, and cucumbers) has a huge impact on our energy use, our “blue water footprint,” and our greenhouse gas emissions. In this action guide, we’ll explore how to eat our greens without emitting so many greenhouse gases.
Planting, growing, harvesting, distributing, preparing, eating, and composting are continual processes. Every meal is an opportunity to take a step toward a more sustainable future that will provide better opportunities for more people to enjoy their time on Earth. I believe the best sustainability step for us to take each week is to educate ourselves so we know what to believe when we see a silly headline like “Research proves salads are more harmful to the environment than burgers” in Beef Magazine.
Help! Does eating lettuce really produce three times more greenhouse gas emissions than eating bacon?
No, it doesn’t. In the normal portion sizes people usually consume, lettuce has far less environmental impact than bacon. You can run the experiment yourself: try growing lettuce in your backyard, then try growing bacon in the same area.
The story that eating lettuce is worse for the planet than eating bacon is so memorable for the same reason any “man bites dog” story is—it’s surprising. And like any man-bites-dog situation, the circumstances are very unusual. The idea was planted and popularized in a 2015 paper by two professors and a grad student from Carnegie Mellon who wondered about the environmental impact of the dietary recommendations to eat more fruits and vegetables, which the United States made in 2010. They decided to compare the environmental impact of food choices on a calorie basis, imagining how much lettuce you’d have to eat to get as many calories as a few slices of fatty bacon.
To get equivalent calories, you’d have to eat two heads of lettuce for every four slices of bacon. If you compare the environmental impact of getting your calories by driving to the grocery store and buying two heads of lettuce versus four slices of pre-cooked bacon, then eating lettuce would produce more greenhouse gas emissions.
In the real world, no one eats just lettuce or just bacon. In fact, you can enjoy a well-balanced, healthy diet without any lettuce or bacon. The real question is whether there are more sustainable items to eat besides lettuce for the benefits it provides (namely, fiber, water, and nutrients), and whether there are more sustainable items to eat besides bacon for its benefits (flavor, fat, and protein).
Help! I understand that for my health I should eat some greens and not just bacon; are there better greens to eat than lettuce?
Lettuce is perfectly fine to eat; it’s not inherently less sustainable than any other leafy green. Lettuce just happens to be the most widely consumed leafy green in the United States. The environmental problem is not that we eat lettuce; it’s that we tend to grow lettuce on one side of our continent and eat it on the other side. Being a highly perishable food item, lettuce requires refrigeration to keep it from spoiling and lots of plastic to keep it from drying out. Transporting, refrigerating, packaging, and then disposing of packaging emits a lot of pollution and creates a lot of unnecessary waste.
There are three things we can do for the sustainability of our salads:
Grow our own lettuce. Packs of lettuce seeds can be distributed for a tiny fraction of the cost of distributing lettuce heads. Lettuce is one of the easiest things to grow in a home garden.
If we can’t grow our own lettuce (I get it; not everyone has the time or space to garden), buy from local farms. Shipping lettuce across town is better for our environment than shipping it across the country.
If we can’t grow our own lettuce and we can’t buy lettuce at a local farmers market, we can at least use reusable produce bags instead of disposable plastic bags when buying lettuce at the grocery store.
Help! How can growing my own lettuce do more for our planet than not eating bacon?
It all depends on how much lettuce and how much bacon you’re eating. It’s good for you to eat large amounts of lettuce for fiber and nutrients. If you choose to eat bacon, it’s best to have just a small amount for flavor and calories. Because you’ll be eating much more lettuce than bacon, when you multiply it out, the impact of your lettuce could well be bigger than the impact of your bacon. Not only that but any time you grow your own food, you could be having a positive environmental impact.
Here are some of the many ways that growing your own lettuce can benefit our planet:
One packet of lettuce seed can supply a lifetime of lettuce. Plant in succession so you have fresh lettuce becoming available as you’re ready to eat it. Let a few plants go to flower, then collect seeds for the next season.
If you can accept giving up a little garden produce to feed your local ecosystem, a few insect pests can boost biodiversity in your yard and provide food for birds, toads, and other interesting animals higher on the food chain.
You can show your family where food comes from, instilling environmental values in future generations.
You can put your own compost to good use, building soil fertility and vitality.
If you select heirloom varieties, you can help maintain the biodiversity of our food supply.
By selecting and saving seeds from the best growers in your garden, you can improve lettuce strains for future generations.
Help! I’d like to try growing my own lettuce, but I’m out of practice. Where can I get some help?
You can find lots of help on the Internet, but I recommend connecting with your state’s cooperative extension for home gardeners. If you’re not familiar with the Cooperative Extension System of the United States, you are in for a treat. As an example, here are a few links to Cooperative Extension garden advice from around the country:
Georgia: Home Garden Lettuce
Wisconsin: Grow Your Own Salad Greens
To take your home gardening to the next level of sustainability, check out the resources provided by organic gardening organizations. The Maine Organic Farmers and Gardeners Association is one of the largest and oldest in the country and provides a great set of resources for free online:
What’s Still Ahead on the Pathway…
Last year, we explored the pathway to sustainable movement, energy, and goods. Now, we’re exploring the pathway to sustainable food to transition from the standard American diet to a healthier-for-our-planet plant-centered diet and transition from industrial to regenerative agriculture. Stay with us on the journey as we blaze a trail to a superbly sustainable future, one practical step at a time.
References and Further Reading
Vegetarian and “Healthy” Diets Could Be More Harmful to the Environment, Carnegie Mellon University
Eating lettuce is three times worse for climate than bacon, say scientists, The Christian Science Monitor
No, Bacon isn’t Greener Than Lettuce, Environmental Working Group
Energy use, blue water footprint, and greenhouse gas emissions for current food consumption patterns and dietary recommendations in the US, Environmental Systems and Decisions
Blue Water Footprint, ScienceDirect
Research proves salads are more harmful to the environment than burgers, Beef Magazine
Man bites dog, Wikipedia
U.S. lettuce production shifts regionally by season, United States Department of Agriculture
What Is The County Extension Office? Access A Wealth Of Local Gardening Knowledge, Gardening Know How
Cooperative Extension System, National Institute of Food and Agriculture USDA
Home Garden Lettuce, University of Georgia Extension
How to Grow Lettuce in Your Garden, Utah State University Extension
Grow Your Own Salad Greens, Wisconsin Horticulture
Learn, Maine Organic Farmers and Gardeners Association (MOFGA)
Lettuce Seed, MOFGA
Seed Planting Calendar, MOFGA
Succession Planting for Continued Yields and Season Extension, MOFGA
Great stuff Fred!