More efficient if you're starving and need some calories immediately without having to gather grass. Not efficient in terms of environmental resources invested

More efficient if you're starving and need some calories immediately without having to gather grass. Not efficient in terms of environmental resources invested. How much grass being eaten by the lamb resulted in a pound of lamb? How much water did the lamb consumer per pound of weight? From the article: >a plant-based burger generates 90% less greenhouse gas emissions, requires 45% less energy, has 99% less impact on water scarcity, and 93% less impact on land use than a ¼ pound of traditional U.S. beef.