That's kind of misleading though, because they're counting water and "meat" separately. Water is itself a major component of cow musculature (50-75% percent, depending on the type of muscle), so this method would conclude that a slab of steak is mostly not-meat.

From a more culinary perspective, you do probably want some fat in your burger. Depending on your tastes, I'm not sure the presence of 'plant matter' is particularly sinister either; I, for one, like a few onions in mine.