The Best Diet for the Planet

Sep 3, 2018


By now, we all know that the food we eat has a huge impact on our health. But producing food requires land, water, nutrients – and in our globalized world – packaging and transportation. And that means that our dietary choices also have a big environmental impact. 



Researchers at the University of New Hampshire, Tufts University, and Hampshire College have pulled together data about the full life cycle of hundreds of foods. Not surprisingly, they find significant differences in the sustainability of different diets, and they say that this kind of information should be incorporated into federal dietary guidelines. 


Miriam Nelson is the president of Hampshire College and she led that work. She also previously led nutrition and sustainability research at the University of New Hampshire and Tufts Universities. And she was an advisor on the most recent U.S. Dietary Guidelines. 

“When we think about our nutrition, we want to make sure that it’s supporting our own health, but we also want to make sure that we aren't causing any harm in the short term or in the long term,” Nelson said. “And that's where we really get into sustainable diets.”


A sustainable diet is one that supports us now, but it’s also one that is respectful to the environment, one that’s socially just, and one that’s economically affordable. According to Nelson, there are indirect health consequences due to some of the ways in which food is produced. Pollution in water and the carbon that has gone up into our atmosphere also affects the workers that are producing the food. 


And Nelson says that all of this can have an indirect impact on our health. It's not just the food that we put into our mouths, but it's also how that food is grown.


The study looked at three patterns of eating that are deemed to be very healthy: a healthy U.S. diet, the Mediterranean style diet, and also the ovo-lacto vegetarian. Nelson and her team then looked at the actual foods that made up those patterns.


After that, they were able to look at the lifecycle assessment for five different parameters for all of these foods: carbon emissions, land use, water use, and water quality, and also air pollution. 


The results showed the healthy vegetarian diet (ovo-lacto) was 42 to 84 percent lower in environmental impacts on four out of five of environmental parameters. 


The next step is to incorporate dietary sustainability into dietary guidelines. If they can do that, Nelson believes, then it can have a big impact internationally.