Because grass-fed cows never eat grain, they always have less fat. (Aldi has good grass-fed ground beef, if you're interested.) Of course, there are other aspects to consider.

Beef: Grass-Fed vs. Grain-Fed Grass-fed beef, as the name implies, comes from cows that eat mostly grass. Grain-fed cows eat a diet that includes soy, corn, and other additives.

Or, from chicken feces, poultry feathers, cow blood or other parts of pigs, horses, fish, cattle and just about any animal part unfit for human consumption.

The cows eat much like they would in any feedlot—a far sight from any pasture. ... It notes that grain-fed beef can still be a nutritious and less expensive source of protein.

This week, NPR's looking at how the food we eat every day affects climate change. We're focusing on solutions that cover everything from how we grow food to how we eat it. So let's talk about beef ...