As a longtime vegetarian, I’ve always been confident that my diet is better for the planet than that of your typical carnivore. But a vegan pal of mine says I could be doing a lot more, by rejecting all animal products—no eggs, no milk, not even the occasional bowl of mac ‘n cheese. Is veganism really that much better for the environment?

Since few Americans have followed Alicia Silverstone’s abstemious lead and renounced animal products altogether, there aren’t many data available on the environmental consequences of veganism. Somewhere between 2 percent and 5 percent of the nation’s eaters classify themselves as vegetarians; of that number, perhaps 5 percent are strict vegans. As a result, most research on meat-free diets has focused on lacto-ovo vegetarians, the milk-and-egg eaters who form the lion’s share of the veggie demographic.

According to a 2005 University of Chicago study, a lacto-ovo vegetarian emits far less greenhouse gas than a counterpart adhering to the standard, meat-rich American diet—the difference is equivalent to around 1.5 metric tons of carbon dioxide per year, assuming the same daily caloric intake. (The study’s authors thus claim that going vegetarian has the same effect on carbon dioxide emissions as switching from a Chevrolet Suburban to a Toyota Camry.) The savings mostly come about because of the disparity between the fossil fuel required to produce a calorie’s worth of grain vs. that needed to make a calorie’s worth of beef; grain is nearly a dozen times more efficient in this regard. Cattle are also a huge source of methane, a particularly noxious greenhouse gas; it’s estimated that bovines are responsible for roughly triple the methane emissions of the American coal industry.

Yet lacto-ovo vegetarians still derive about 14 percent of their calories from animal products. Bring that number down to zero, as strict vegans do, and you’ll certainly ratchet down your carbon emissions by another several hundred pounds per year. “If we put [greenhouse gas] emissions above all else, then veganism beats lacto-ovo vegetarianism handily,” says Gidon Eshel, a co-author of the University of Chicago study. “That much is clear and unequivocal.”

But Eshel hastens to add—and The Lantern wholeheartedly agrees—that your vegan acquaintance isn’t necessarily some environmental saint. That’s because direct carbon dioxide emissions are only part of the story when it comes to food’s eco-impact. You also have to look at the issue of land use—specifically how much and what sort of land is required to sustain an agricultural enterprise. In a region with poor-to-mediocre soil, for example, it may be more efficient to operate a well-managed egg farm than to try growing vegetables that can’t flourish under such conditions. And animals are handy at consuming low-quality grain that isn’t necessarily fit for human consumption. (Rather than going to waste, that grain can help create nutrient-rich dairy products.) In fact, a recent Cornell University study concluded that modest carnivorousness may actually be better for the environment than outright vegetarianism, since cattle can graze on inferior land not suitable for crops. Squeezing more calories out of the land means that less food needs be imported from elsewhere, thereby reducing the burning of fossil fuels.

That’s music to the ears of The Lantern, a devoted meat-eater who weeps at the very thought of life without bacon cheeseburgers and curry goat. But there are important caveats to the Cornell study: First, its calculations assume that all meat is raised locally, rather than frozen and trucked cross-country; second, the study recommended that to optimize land use, residents of New York state (where the research was conducted) limit their meat and egg consumption to two cooked ounces per day—3.8 ounces less than the national average.

Though The Lantern admires the ascetic fortitude of vegetarians and vegans, it’s pretty unrealistic to expect the majority of adult Americans to forgo steak for the benefit of the planet. At the same time, agriculture is responsible for between 17 percent and 20 percent of the nation’s energy consumption. So instead of hectoring people to become vegetarians—a tactic that causes many Americans to roll their eyes—perhaps we should start by urging consumers to be more cognizant of exactly how much energy it takes to produce and transport an Extra-Long Bacon Cheddar Cheesesteak. And it wouldn’t hurt if people got wise to the fact that meat needn’t be the focus of every breakfast, lunch, and dinner.

That’s going to be a serious challenge, however, considering that per capita meat consumption rose by 40 percent in the United States between 1961 and 2002. One hopes that the Chinese don’t follow our gluttonous lead, but the news so far isn’t encouraging: Meat consumption in China has already doubled over the past decade.