Some Americans may have gotten the message that our fondness for beef is harmful to the environment. A recent study from the Natural Resources Defense Council (NRDC) found that America's beef consumption fell about 19 percent between 2005 and 2014, avoiding "185 MMT of climate-warming pollution." To help translate how much pollution that is, the NRDC says it's the "equivalent of the annual tailpipe emissions of approximately 39 million cars."

The production of meat, particularly beef, causes the most environmental damage of all the foods American's consume. For every kilogram (2.2 pounds) of beef produced, 26 kilograms (57.3 pounds) of carbon dioxide are emitted.

But beef isn't the only damaging food we're eating less of. In that same time frame, consumption of orange juice, pork, whole milk, and chicken was down, too, as was the environmental harm that the production of those foods create. All-in-all, the diet-related climate-warming pollution from the foods American's eat has dropped by about 10 percent in the past decade, or the equivalent of the pollution by 57 car tailpipes in one year.

Consumption is down, but not for all impact foods

grated-parmesa America's cheese consumption has risen over the past 10 years. (Photo: Emily/flickr)

While Americans are consuming fewer of the foods that create significant environmental impact, there are some foods that we're consuming more of including cheese, yogurt, butter and asparagus, according to the NRDC.

Asparagus? The report didn't go into detail about how bad perennial asparagus is for the environment, but I was curious. According to National Geographic, the bulk of the climate-warming pollution associated with asparagus has to do with how it travels. It's transported mostly by air, often from Peru, using 50 times more energy than if it was shipped by sea, 33 times more than if it traveled by train, and four times more than if it was trucked from farm to store.

The NDRC argues that if Americans had curbed their consumption of these foods, too, our food-related carbon footprint would have been reduced even further over the past decade. The goal is to reduce consumption of all foods that have a big carbon footprint.

The top five greenhouse gas-intensive foods Americans consumed in 2014 were beef (34 percent of the total food-related greenhouse gas emissions), chicken (8 percent), pork (7 percent), eggs (3 percent) and cheese (8 percent). All other foods combined made up the remainder of the food-related greenhouse gas emissions.

So there is definitely some good news here and some incentive to reduce consumption of beef, dairy products (and non-local asparagus) even further.

There's one thing that the report didn't touch on that I'm left wondering about, though. The report focused on the consumption of beef and other foods by Americans, but it didn't touch on the production of those foods in America.

In 2015, America exported $6.3 billion of beef, and while that was down a bit from the previous year, that's still a lot of cow. So, I wonder if even though Americans are eating less beef, is America is producing less beef? If not, is our diet-related pollution savings being cancelled out by those eating American-produced beef in other countries?

Robin Shreeves ( @rshreeves ) focuses on food from a family perspective from her home base in New Jersey.