You're walking down the meat isle at your favorite grocery store to pick up a couple pounds of grass-fed beef. You've done some research. You know that grass-fed beef is more healthy as it contains more antioxidants, vitamins, CLAs and omega 3 essential fatty acids. You know cattle were never meant to eat grain in the first place. You feel good. You move on. The problem is that what you are buying is likely not what you thought it was. Unfortunately, the term "grass-fed" is not regulated and often times, misused by industry marketing. Any cattle that has had access to grass during it's life can be called "grass-fed". So the animal is often raised on pasture and then shipped off to the feed lot to be finished on a corn based gain diet. This is more accurately grass-fed / grain-finished. The exact thing you were trying to avoid. So how do you know what to buy?
If you are shopping at a store, look for the proper labels. There are a few terms such as "100% grass-fed" or "grass-fed / grass-finished" that you can feel a little better about. Also, there is a organization called the American Grassfed Association. AGA-Certified beef has what you are looking for. In order to meet their standards the animals are fed only grass and forage from weaning until harvest, are raised on pasture without confinement to feedlots, are never treated with antibiotics or growth hormones, and raised on American farms. The AGA logo is green with four clumps of grass and says "American Grassfed."
An even better way is to talk the guy who raised it. While this is nearly impossible to do at the store, you can do it at the farm or ranch. Visit the farm and talk to the farmer. Ask him questions and find out what practices their farm uses. We call this "customer certified" and it's about as good as you're going to get.