In overpopulated countries is eating steak an inefficient way to use food energy?

Yes.

To get a steak you have to spend a lot of energy on growing plants as food for the animal that will become the steak. And animals aren't that good at turning plants into meat, so you have to feed them a lot more than they produce.

If you grow plants to feed to people directly instead, bypassing the animal, the same amount of plants will feed a lot more people than the animal did.