If you choose to eat meat, choose wisely. In addition to being lower in overall fat, grass-fed beef contains less “bad” fat (including saturated fat) than feedlot beef and delivers two to six times more omega-3 fatty acids. But how do you know if your meat is 100 percent grass fed?

“All cattle are grass fed at some point in their life,” says Tai Jacober, cofounder of Colorado- based Crystal River Meats. “What’s important is if they’re also finished [that is, fattened before processing] on grass.” Typically, feedlots finish cattle for 90 to 160 days on corn because it’s cheap and adds fat quickly.

Why should a few days of corn matter if the animal is primarily raised on grass? Actually, nutrient profile can significantly change.

During grain finishing, levels of important nutrients like body-fat-reducing conjugated linoleic acid (CLA) and heart-healthy omega-3s dramatically decrease. For the most nutrients, look for USDA Grass Fed or American Grassfed labels on beef packaging; or consult your natural retailer for more information.