The average American eats twice as many kilograms of meat than the next nationality (last time I checked it was the British). As the article states, beef is by far the most environmentally draining; it turns out in terms of protein and calories, pork is nearly the same as beef with a much smaller amount of energy required to produce that meat. If the US had a better food culture [I'm not counting fast food here], we might be able to actually change the mindsets of the public that they dont need a meat entre with every meal.