It’s a no-brainer that a vegetarian diet takes less of a toll on the environment than a carnivorous one. The logic goes like this: feeding plants to animals, and then eating the animals, is more wasteful, costly and polluting than simply eating the plants. Typically, conclusions from the scientific literature assert that a non-vegetarian diet consumed 2.9 times more water, 2.5 times more primary energy, 13 times more fertilizer, and 1.4 times more pesticide than a vegetarian diet.
However, a new round of research shows that the argument is not as clear cut as you would think.
All meat is not created equal. For example, cows have a much bigger environmental footprint than chickens. Ruminants—cows, sheep, and goats—have a four-chambered stomach. They digest plants through fermentation, which in turn produces methane, a damaging greenhouse gas. Ruminants also have less efficient feed conversion rates.
According to the Washington Post, “It takes six pounds of feed to make one pound of beef, but only 3.5 pounds for pork and two pounds for chicken.” Chicken, turkey, and pigs, on the other hand, have only one stomach and are thus referred to as monogastrics. Their feed conversion ratios are much more energy efficient.
And regardless of the kind of meat, previous calculations that rank emissions by kilogram are not truly representative. Measuring a food’s carbon footprint in terms of weight—how many kilograms of greenhouse gasses a kilo of food generates—is fundamentally flawed. Comparing a kilo of beef to a kilo of broccoli is not apples to apples, as the two foods run the gamut in terms of nutritional density. Look at it this way: To get the same amount of calories, you would need 6.7 kilos of broccoli for every one kilo of beef. Comparing calories, not kilos, is a game changer. Producing six kilos of broccoli has a much bigger environmental toll than merely one.
When you start to compare calories versus kilos, the data shows surprising results. Calorie for calorie, broccoli and tomatoes generate more greenhouse gasses than chicken. It’s enough to give pause to the claim that vegetarianism is kinder to the planet. Measuring a food’s carbon footprint becomes an exercise in nuance. It requires less of an either/or mindset and more of a both/and approach.
Here are three tips for a more environmentally friendly diet:
Eat vegetarian at least one meal a day
Nuts, lentils and beans have the lowest scores for environmental impact and are full of protein. Opting to replace meat with lentils/beans at least one meal a day will do wonders for reducing global emissions (although you might experience a significant increase in personal emissions).
Discriminate amongst meat
Thinking less cow and more chicken, less lamb and more pork is the savviest approach to mitigating one’s dietary footprint. Lamb is the worst polluter, followed by beef, whereas chicken and pork come in at under half.
Buy organic
According to the EWG, meat, eggs and dairy products that are certified organic, humane and/or grass-fed are generally the least environmentally damaging.
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As a blog bonus, the following statistics from a breakthrough EWG report reveal the surprising impact of our dietary choices. Sure does make having a turkey burger—hold the cheese—mighty appealing. Here’s how eating less meat measures up against other climate-saving actions:
Over a year:
- If you eat one less burger a week, it’s like taking your car off the road for 320 miles or line-drying your clothes half the time.
- If your four-person family skips meat and cheese one day a week, it’s like taking your car off the road for five weeks – or reducing everyone’s daily showers by 3 minutes.
- If your four-person family skips steak once a week, it’s like taking your car off the road for nearly three months.
- If everyone in the U.S. ate no meat or cheese just one day a week, it would be like not driving 91 billion miles – or taking 7.6 million cars off the road.