Less Meat: good news for land use

MeatVsSoyWhat’s your Food Print?

As I discuss in “Feed Your Vegetarian Teen“, one good argument for eating less meat is land use.  The Earth has a finite amount of arable land to grow crops.  Right now livestock consume a significant portion of those crops.  That’s a very inefficient way to produce protein-rich food for human consumption.  With global population exploding, we don’t have enough land available to feed everyone a lot of meat.

A new report examines land use needs in the US for 10 different types of diets, from the typical meat-heavy American diet to a vegan diet.  Two key findings are:

  1. To sustain the average American diet, 80% of available cropland must be used to grow animal feed crops.  This diet requires 8 X more land per person than a vegan diet.
  2. A lacto-vegetarian diet (with dairy products) fed the most people for the available land.

The researchers compared the 10 diet types based on a daily intake of 2150 calories.  Fat varied from a low of 66 grams for the vegan diet to a high of 120 grams for the average American diet.  Protein ranged from 74 grams for the vegan diet to 92 grams for our current diet.  Keep in mind, 74 grams of vegan plant-based protein should be adequate for daily needs, even considering that plant proteins are lower quality than animal proteins.  The vegan protein foods included tofu, soy milk, dried legumes, nuts while the typical American diet was all about meat, with some milk and eggs.

Land Use

So how much land would be used?  The land use requirement to produce each diet ranged from a high of 1.08 hectares per person per year for the average American diet to 0.13 for a vegan diet.  So why wasn’t a purely vegan diet deemed the best use of crop land for feeding people?  It has to do with what the researchers call “carrying capacity” of the land.  As I understand the definition, it refers to the number of people who can be fed from the land available to grow the necessary crops for each diet.  The lacto-vegetarian diet came out best, with the capacity to feed 261% of the 2010 population of the US.  Interestingly, the vegan diet trailed slightly behind even the lacto-ovo-vegetarian diet and the two low-meat diets.

Of course, a theoretical diet used in a study like this might not correspond exactly to the low-meat or vegetarian or vegan diet you choose.  One thing this study did not examine was energy use in agriculture.  Livestock agriculture uses large amounts of energy and water.  Plant-based diets should use less.  But there’s a catch here: 21st Century vegan and vegetarian diets in the US rely increasingly on highly processed fake meat.  So while switching to a vegan diet might seem environmentally virtuous, it might not be if you diet is heavy on soy burgers and fake chicken bits.

I’m starting to feel old fashioned when I advocate for a plant-based diet that actually includes plants in close-to-natural form, before big food corporations figured out ways to make the humble soy bean look and sort-of taste like a chicken nugget.

Take Away Message

Human health is improved by lower meat plant-based diets.  And evidence is mounting that environmental health also benefits.  Our ability to feed the growing global population a healthy diet depends on smart use of cropland, and the diet you choose impacts the sustainability of that system.

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