The West Wasn't Won; It's Being Destroyed

Saw a bumper sticker today on an old pickup truck with aggressive tires.  It said "Eat More Beef; the West Wasn't Won on Salad."  I a nutshell, it expresses the attitude that has contributed to the destruction of the West.  How do large herbivores like antelope, hippopotami, and elephants get so strong eating their versions of salad?  Maybe we'll learn some day.