It’s better for the environment than meat, but soy comes with its own eco challenges

QUESTION: I have heard that the production of soy is actually quite bad from a sustainability point of view. As a vegetarian, what are my best options in terms of soy products (if indeed there are good options), or if not soy products, what are other good alternatives that provide the protein that soy does? Asked by Marc Evans, Stanford, Calif.

ANSWER: As a strict vegetarian, I know how easy it is to fall into the trap of eating copious amounts of soy. I spend so much time explaining my choice not to eat meat that I sometimes forget to think closely about what I am putting in my body. You’re right though, there are serious issues with the way some soy is grown. The short answer is that eating soy is almost always more environmentally friendly than eating meat. But there are still good reasons to pause before making tofu your only source of protein and patting yourself on the back for being green.

Eating soy, like the soybeans pictured here, is almost always more environmentally friendly than eating meat. But there are still good reasons to pause before making tofu your only source of protein and patting yourself on the back for being green. (Photo courtesy of creative commons,

Soy is a complicated little bean. In an individual’s diet, it can be a healthy source of protein and fiber. But as a global commodity crop, it can leave a devastating environmental footprint. I took my questions about soy production to Professor Rosamond Naylor, director of Stanford’s Center for Food Security and the Environment. She told me that problems with soy come from relatively recent changes in how and where it is grown. We’re not just talking about hoards of vegans who want their soymilk: Today, most of the 260 million ton global soy crop is fed to animals or converted into biofuels. Today, more than 90 percent of the soy grown in the United States has been genetically modified, primarily to stand up to common herbicides. And as the crop has become increasingly valuable on global markets, vast areas of tropical forest and savannah, especially in Brazil, have been clearcut to make way for horizon-spanning plantations.

In 2011, genetically modified (GM) soy was the leading genetically modified crop globally – occupying some 185 million acres of land area, or nearly twice the land area of California. GM crops make it easier for farmers to produce an abundant harvest. The problem is that extensive GM crop use is actually an environmentally dangerous practice. When farmers’ fields are home to only a single crop, farmers are much more susceptible to disastrous crop failure—if a pathogen infected the soy, the entire crop would be gone.  Creating strains of soy that are resistant to herbicides can also cause farmers to use more of those herbicides to combat weeds that develop an herbicide resistance. Residues from these chemicals can remain on the plants and have been linked to severe health problems for farm workers, and potentially for consumers. GM crops also make farmers dependent on the agricultural biotechnology companies that synthesize their seeds. Unfortunately, the world’s largest producers of soy—the United States, Brazil and Argentina—rely heavily on GM soybeans. Check out the Nitty Gritty answer for more on the environmental and health impacts of GM soy.

Deforestation in the Amazon rainforest and Brazilian savannah (or cerrado) is an equally disturbing problem driven by soy production. The United States and Brazil are fighting for the lead in the global market for soy, and Brazil has relied on cropland expansion to increase their production levels.

Destroying these biodiversity hotspots means losing the many native plant and animal species, like the jaguar, the fox-like maned wolf, and the hairy-eared cerrado mouse, which thrives only in these habitats. Deforestation also means chopping down photosynthesizing trees that regulate our atmospheric carbon. Soy production that drives this land conversion is certainly not environmentally friendly. The key to eating the right kind of soy is choosing soy products that are produced locally and organically. These local, certified-organic products are not contributing to Amazonian deforestation and are guaranteed to be GM free.

What happens after soy reaches our mouths? Soy is a great source of vegetarian protein, but it’s not the only one. Vegetarians who do not eat soy or are avoiding the wrong kinds of soy can get the necessary protein from other sources. According to the USDA Dietary Reference Intakes, adults should eat about 0.36 grams of protein per pound of weight, every day. For a 140-pound person, that means 50.4 grams of protein per day, or a little less than 2 ounces of pure protein. Eggs can be a good source of protein for non-vegan vegetarians – one egg contains about 6 grams of protein. Egg-eaters can be environmentally conscious by buying free range, organic (no antibiotics, fed with organic feeds) eggs. But there are also plenty of soy-free, vegan food alternatives that provide even greater amounts of protein. The chart below lists many of these delicious alternatives, such as the meat substitute seitan, made from congealed wheat gluten, and many protein-rich grains and beans. Tempeh and textured vegetable protein are soy products.

We should consider the place of soy in our diets the same way we consider everything else that we eat – by understanding where our food comes from and the impact it has on our health. Can you eat sustainable soy? Yes. Are there vegetarian substitutes for soy that will give you the right amount of protein? Absolutely. Are there any foods that will always be sustainable, no matter where they are grown? No, probably not, because food is necessarily linked to the way it is grown, harvested, and shipped. So keep thinking and keep eating.

Check out the Nitty Gritty answer for more on the environmental and health impacts of GM soy.

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