To be clear, all cattle are fed grass at first. It is what happens after the first 7-9 months of their existence that changes things. It is estimated that around 80% of cows in the U.S. are eventually moved into what is known as concentrated animal feeding operations, or CAFOs. At these feedlots, the cattle’s main food source becomes grain, more particularly soy- or corn-based food. This is done for a few different reasons. One is to free up land space. Grain is also cheaper and easier to grow than grass. Another reason is that grain fattens up the cattle at a faster pace. Cows that feed primarily on grass don’t grow — muscle- and meat-wise — at the same rate as grain-fed cattle do. One reason is that grain contains more energy.
This change from their feeding natural habitat, however, alters the molecular and chemical makeup of the meat, explained nutritionist Peter Osborne. “Most of your grains are extremely high in omega-6 fatty acids.” Feeding cattle a primarily omega-6 fatty acid-rich diet changes the fatty acid composition of the meat, per the expert. “It drives it up to a very high level of omega-6 and a very low level of omega-3,” shared Osborne.
Grass-fed beef (and therefore, steak), on the other hand, contains up to five times more omega-3 fatty acids. Omega-3 fatty acids have a lot of health benefits, including combating depression and anxiety; boosting eye, bone, joint, and brain health; lowering inflammation; and reducing symptoms of metabolic syndrome.