Study finds that lettuce is three times worse for the planet than bacon.
Despite repeated warnings that livestock contribute significantly to climate change, a recent study conducted at Carnegie Mellon University finds that it’s our fruits, vegetables, dairy, and seafood that we should be worried about.
To arrive at this conclusion, the research team calculated the energy use, blue water footprint, and greenhouse gas (GHG) emissions for two different diets: the current diet of the average American, and the healthier diet recommended by the 2010 United States Department of Agriculture (USDA) Dietary Guidelines. Shockingly, it is the healthier diet that has the greatest impact in all three categories. If you follow the USDA recommended diet, you’ll be wasting 38 percent more energy, using 10 percent more water, and emitting 6 percent more greenhouse gases.
The study, which was co-authored by Paul Fishbeck, a professor of social decisions, sciences and engineering, and public policy, Michelle Tom, a PhD student in civil and environmental engineering, and Christ Hendrickson, a professor of civil and environmental engineering, took into account how different foods are grown, processed, transported, displayed in stores, and stored in your home.
"Eating lettuce is over three times worse in greenhouse gas emissions than eating bacon," said Fischbeck, in a press release. "Lots of common vegetables require more resources per calorie than you would think. Eggplant, celery and cucumbers look particularly bad when compared to pork or chicken."
But we all know that you’d have to eat a lot of lettuce in order to consume the same number of calories as there are in a single slice of bacon. What if you want to reduce your calorie intake when you switch from a typical American diet to a vegetable-based diet? Wouldn’t this reduce your carbon footprint?
Strangely enough, no.
According to the study, which was funded by CMI’s Steinbrenner Institute for Environmental Education and Research and the Colcom Foundation, following the USDA Dietary Guidelines and reducing your caloric intake is actually worse than maintaining a high caloric intake on the recommended diet.
“These perhaps counterintuitive results are primarily due to USDA recommendations for greater Caloric intake of fruits, vegetables, dairy, and fish/seafood which,” the authors write in their report, “Have relatively high resource use and emissions per Calorie.”
But according to the study, we don’t have to choose between obesity and climate change. The researchers also examined a typical American diet but with reduced caloric intake, finding that we can potentially maintain a healthy weight by simply reducing how much we eat. Not only would this solution tackle obesity, but it would also reduce our impact on the planet.
"There's a complex relationship between diet and the environment," Tom said. "What is good for us health-wise isn't always what's best for the environment.”