Wednesday, October 21, 2009

Tofu too?!?!

Great. Someone asked Slate's Green Lantern about the environmental impact of tofu and reminded me and my fellow eco-eaters that the soy-based protein source also comes with a price. Luckily though, a much lower price than meat. Well, most meat. Nina Shen Rastogi for Slate responds:

"Not all meat is created equally when it comes to environmental impacts. Producing a calorie of chicken protein requires only a fraction of the energy that it takes to churn out a calorie of beef protein. Chickens also produce significantly lower levels of greenhouse gases, thanks in part to their dainty diet and the fact that, unlike ruminant animals, they don't go around expelling methane from their mouths and rear ends.

So where does tofu fit into this picture? Soybeans themselves are a highly efficient source of protein: According to one recent study, it takes about 0.2 calories of fossil fuels to make a calorie of soybean protein, a little more than one-thirtieth of the total for chicken. Soy is also much better from a global-warming perspective: In conventional production, a kilogram of raw beans generates about 150 grams to 300 grams of carbon-dioxide equivalent, as opposed to 2,500 grams for the equivalent quantity of edible chicken meat. (Organic soybeans should produce even less CO2 equivalent. [PDF])

But then, we're not talking about eating soybeans in their natural form. As you note in your question, it takes some work to make beans into tofu. Soybeans are soaked in large tanks and ground into a slurry that then gets heated, filtered, and coagulated into slabs before being chopped up, packaged, and pasteurized. All of these steps require energy—and they dramatically increase tofu's carbon footprint...

...So we don't know exactly where American tofu falls on the spectrum of greenhouse gas intensity, but we can draw at least one commonsense conclusion: Your potential savings will depend on what you're swapping out in the first place. If every dinner you serve contains beef or air-freighted fish, then switching to tofu every once in a while will make a real difference. If you eat mostly chicken, your savings would be less impressive."

The good news is, most of the tofu consumed in America comes from native-grown soy beans which means we aren't contributing to the destruction of the Amazon - which was my biggest fear when the headline got my wheels turning. Whew!

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