Earlier quoted context omitted.
Carbon footprint for meat is significantly higher because you have to grow the plans and feed it to the animals, and moving up a trophic level is usually ~10% efficient. It's much more efficient to consume the plants directly.
> It's much more efficient to consume the plants directly. We can't consume most plants directly, and the ones that we do, we consume only a tiny minority of the plant (most of the time).
So do the animals. The soy and wheat we feed the animals is a tiny portion of the plant... so what? If we have 1000 calories of wheat, it's better to feed that to a human, than a cow; The cow will only produce 100 calories of meat for the same grains that we would have eaten.