Vegetarian and ‘healthy’ diets are more harmful to the environment: Carnegie Mellon study

Contrary to recent headlines — and a talk by actor Arnold Schwarzenegger at the United Nations Paris Climate Change Conference — eating a vegetarian diet could contribute to climate change.

In fact, according to new research from Carnegie Mellon University, following the USDA recommendations to consume more fruits, vegetables, dairy and seafood is more harmful to the environment because those foods have relatively high resource uses and greenhouse gas (GHG) emissions per calorie. Published in Environment Systems and Decisions, the study measured the changes in energy use, blue water footprint and GHG emissions associated with U.S. food consumption patterns.

“Eating lettuce is over three times worse in greenhouse gas emissions than eating bacon,” said Paul Fischbeck, professor of social and decisions sciences and engineering and public policy. “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.”

Fischbeck, Michelle Tom, a Ph.D. student in civil and environmental engineering, and Chris Hendrickson, the Hamerschlag University Professor of Civil and Environmental Engineering, studied the food supply chain to determine how the obesity epidemic in the U.S. is affecting the environment. Specifically, they examined how growing, processing and transporting food, food sales and service, and household storage and use take a toll on resources in the form of energy use, water use and GHG emissions.

On one hand, the results showed that getting our weight under control and eating fewer calories, has a positive effect on the environment and reduces energy use, water use and GHG emissions from the food supply chain by approximately 9 percent.

However, eating the recommended “healthier” foods — a mix of fruits, vegetables, dairy and seafood — increased the environmental impact in all three categories: Energy use went up by 38 percent, water use by 10 percent and GHG emissions by 6 percent.

“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. That’s important for public officials to know and for them to be cognizant of these tradeoffs as they develop or continue to develop dietary guidelines in the future.”

CMU’s Steinbrenner Institute for Environmental Education and Research and the Colcom Foundation funded this research.

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6 Responses to Vegetarian and ‘healthy’ diets are more harmful to the environment: Carnegie Mellon study

  1. Anne Hosking RN says:

    I found this article a little hard to believe and wondered who had sponsored it. I did a brief google search and found this: http://www.huffingtonpost.com/2014/10/13/food-water-footprint_n_5952862.html

  2. Janet Oconnell says:

    And he study was paid for by who? Monsanto Dow The American Beef or Pork Councils?

  3. W. E. Feeman, jr, MD says:

    On the other hand, cows are a major source of methane, which contributes to global warming.

    • Bonnie Modugno, MS, RD says:

      We cannot compartmentalize the impact of grazing animals on the environment. Early research only focused two factors: water usage and methane expulsion with emphasis on the CAFO environment. There was no comprehensive assessment of the costs and benefits of the animals on the land.

      Those who know agriculture and cattle appreciate the costs to the environment of all human activity. It’s the animals that give back and offer us the opportunity to recycle nutrients, feed microbes, enhance soil ecology and fertility, improve water flow and filtration, and sequester carbon. Enough has been written that we all need to appreciate two key truths about grazing animals. They are essential for regenerating the soil and regenerated soils have the capacity to reverse climate change.

      Good reads include Defending Beef by Nicolette Hahn, The Soil Will Save Us by Kristin Ohlson, and Cows Will Save Us by Judith Schwartz.

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