Vegetarian diet more harmful to environment, says study

Contrary to popular assumption -- and a talk by actor Arnold Schwarzenegger at the United Nations Paris Climate Change Conference -- eating a vegetarian diet could contribute more to climate change than eating a non-vegetarian diet, warns a new study.

Schwarzenegger, a former California governor, advised people to go meat-free one or two days a week to help protect the climate.

But the new research found that consuming 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.

"Eating lettuce is over three times worse in greenhouse gas emissions than eating bacon," said one of the researchers Paul Fischbeck, professor at Carnegie Mellon University in the US.

"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 said.

The study measured the changes in energy use, blue water footprint and GHG emissions associated with US food consumption patterns.

The researchers studied the food supply chain to determine how the obesity epidemic in the US 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 the 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 nine 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 six percent.

The findings appeared in the journal Environment Systems and Decisions.