Why is it more efficient for a human to be a vegetarian?

Answer 1

This is actually debatable. On the pro side of the argument, vegetarianism is more efficient because it takes less land mass, less energy and creates less carbon emissions to produce a pound of vegetables than to produce a pound of meat.

On the con side of the argument, vegetarianism is less efficient because the equivalent volume of vegetables has less caloric energy than the same volume of meat. Also, it is very difficult to get adequate amounts of all the essential amino acids from non-animal sources. Another argument against the energy efficiency of vegetarianism is that currently meat production is taking place on non-agricultural land, marginal land that is not fertile enough for plant production. If a large enough proportion of the human population stopped eating meat, there would not be enough food to go around because there is insufficient fertile farmland available to provide that much food.