Larkburger, a small but growing chain of “fast casual” restaurants in Colorado, calls itself eco-friendly. As it happens, the company has taken a thoughtful approach to limiting its environmental footprint. It generates almost no waste, using utensils made out of potatoes, and cups made of corn that can be composted along with its food waste. It uses recycled mesquite wood to decorate the walls. It buys wind energy to offset its electricity use.

These are not trivial gestures. They all cost money. Larkburger’s president, Adam Baker, recently told me: “The trash bags that we use are compostable. They’re a dollar apiece. I look at those and say, I wish that they would make it cheaper. But it’s part of our DNA. It’s part of what we do.”

One more thing to know about Larkburger: The  burger is really good. I set aside my mostly-vegetarian diet to try a Larkburger ($5.95) with Truffle & Parmesan Fries ($2.95). Yum! You don’t have to take my word for it. Judges at the Denver burger battle crowned the Larkburger the best in show, as it bested 11 other burgers at the competition last summer.

But–and you knew this was coming–the question is, can a restaurant that serves beef, and presumably wants to sell more of it all the time,  really be eco-friendly? By most accounts — here’s an overview from WWF — beef has negative environmental impacts, on greenhouse gas emissions, water and land use. It’s a very inefficient, albeit tasty, way to deliver the protein we need.

This isn’t just a question about beef. It’s the kind of thing that comes up all the time when we think about consuming more sustainably. Should we feel better about bottled water if the bottles are made from recycled content, or try to wean ourselves off bottled water altogether? How should we think about a 15,000 square foot “eco-mansion”? (Not well–that’s a pretty easy one.) What about “the world’s first and only full-size Luxury hybrid SUV“?

On a visit last week to Denver, I asked Larkburger’s Adam Baker how he felt about selling hamburgers.

“Conflicted,” he replied. “I love hamburgers. I was raised on hamburgers. Hamburgers are America. That said, how can we be responsible, given that we love to eat hamburgers?”

In fairness to Adam, “green” was never core to the idea of Larkburger. The idea to start a casual but high-quality burger restaurant arose because of the popularity of the Larkburger, which was originally served at the Larkspur Restaurant, a high-end eatery at the base of Vail Mountain. The burger was the creation of the Larkspur chef, Thomas Salamunovich, who is Adam’s partner in the burger chain. They opened their first Larkburger in Edwards, CO, in 2006. Today, there are nine outlets, all in Colorado, with three more on the way. The restaurants compete in a segment that includes Chipotle, Panera Bread and Noodles & Co.

Adam told me: “We wanted to source our food responsibly. We wanted to serve food in responsible sizes. And, as we started looking at how we were going to make our food and serve it, we realized that we were going to generate a lot of waste, and that wasn’t OK.” For a time, he operated his own truck on used from the first Larkburger. “I would literally take the oil home from the restaurant when it was done, take it home, filter it, and put it in my gas tank,” he said. Like many Coloradoans, Adam, 41, who grew up in the Boston area, moved out to the Rockies to ski and enjoys the outdoors.

When buying beef, Adam told me, he had to focus on food quality and safety. “What we are really trying to do is make the best hamburger you can eat,” he said.  They chose to buy their certified Angus beef from a big supplier, National Beef, which has a processing plant in Dodge City, Kansas. The beef is grass fed at first, but then fattened up on grain. “The grass-fed, grass-finished versus the traditional grass-raised, grain-finished is a very heated debate,” Adam said.

He’s right about that. Jason Clay of WWF, a prominent environmentalist who specializes in agriculture, has suggested that raising animals in the much-maligned CAFOs (confined animal feeding operations) may be better for the planet. (See my 2011 blogpost, How to Green a Hamburger). But Nicolette Hahn Niman, the environmentalist-turned-rancher, favors grass-fed beef like the ones she and her husband, Bill Niman, raise at BN Ranch. (See my blogpost, Nicolette Hahn Niman: The carnivore’s dilemma)

As Larkburger grows bigger, Adam says, he’ll have the buying power to negotiate with suppliers and focus on obtaining beef, potatoes, greens and other ingredients with a smaller footprint. “All other things being equal, local and organic is the way to go,” he says, “but it’s not feasible for us now.”

While reporting this story, I stumbled across another gourmet burger chain, Elevation Burger, which says it serves “100% USDA certified organic, grass-fed, 100% free range, 100% ground on premise beef.” I’m looking forward to trying one.

Meantime, if we choose to eat meat, we should probably choose to (1) eat less of it and (2) eat meat from purveyors who pay attention to their environmental footprint. Larkburger strikes me as a step in the right direction.