Switching to a vegetarian diet may take a higher toll on the environment according to the findings of a Carnegie Mellon University study.
The study took into consideration the dietary guidelines suggested by the U.S. Agriculture Department. Published in 2010, the dietary guidelines suggest a switch from energy-intensive foods (mainly consumption of meat) to a diversified diet. The diet should include more fruit, vegetables, seafood.
Arguably, that is the healthy way to go. A diversified diet means a variety of nutrients feeding our body in a healthy manner. Yet, according to the Carnegie Mellon University study, switching to a vegetarian diet may take a higher toll on the environment. Taken step by step, a dietary switch following the 2010 dietary guidelines would result in a 10 percent higher water consumption, 38 percent more intensive energy use and a 6 percent bump in greenhouse gas emissions.
Taken per-calorie basis, food groups like vegetables, fruits, seafood and dairy were found to be resource-intensive. A full life cycle assessment showed that lettuce for instance produces three times more greenhouse gas emissions than the all-time favorite bacon.
According to Professor of social and decisional sciences and engineering Paul Fischbeck, there is really little evidence backing the assumption that a vegetarian diet affects the environment in a positive way. Some fruits and vegetables require more energy use and water consumption to be grown. At the same time, costs associated with transport, plus the greenhouse gas emissions thus resulting make them more energy and cost intensive, as well as more harmful for the environment.
Let’s take the case of lettuce as analyzed by the Carnegie Mellon University researchers. To reach the same caloric intake from two smoked bacon rashers, one would need to eat at least two lettuce. With such a high demand, the transport greenhouse gas emission are higher per calorie than in the case of transporting pork. Or bacon in this case. Unless it’s locally grown, lettuce also deteriorates faster. This adds to the greenhouse gas emissions from food waste.
Not all fruit and vegetables are created equally. Cabbage or broccoli or Brussels sprouts fare much better in helping the environment. The life cycle assessment of cabbage shows that the greenhouse gas emissions are only one fifth of those for pork per calorie. In the case of broccoli, under half of the emissions are accounted for.
To understand how switching to a vegetarian diet may take a higher toll on the environment, the Carnegie Mellon University researchers conducted their analysis on 100 foods. Life cycle assessment played an important role in quantifying the greenhouse gas emissions for each of the foods taken into consideration.
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