Carnivory--God planned or Satan induced?

Note: Although these ideas stray from the problem of pain, as I searched for an idea to blog about, my mind kept getting stuck on how Lewis connected animal carnivory to the fall. He seemed to reject the idea that God biologically programmed animals that way. As a result, I have a blog with questions that came out of my thinking.

Gen 1:29-30 says, “And to all the beasts of the earth and all the birds of the air and all the creatures that move on the ground—everything that has breathe of life in it—I give every green plant for food. And it was so,” and God said the same for humans (NIV). I believe that most people translate this verse as saying God made plants for animals and people to eat and nothing else. However, when I read this verse or its context I cannot find God telling us—humans and animals—to never eat meat. It is true that eating meat in the Old Testament was seen as unclean. (I’m unsure if this was all meat or only some). Yet, Lewis seems to be saying that any kind of carnivory that scientific evidence shows before humans entered into the world was of Satan’s corrupting. I have difficulty acknowledging this idea.

I first hesitate to believe that animals were only herbivores from an idea even Lewis mentions, the idea that if all animals ate plants, they would end of dying from the lack or plant resources so why would God create animals to live in a place where they’re eventually going to starve if they lived off of one food source?

Secondly, for me Lewis’ suggestion that Satan caused animals to live by destroying others for food before the human race entered into the world seems to give Satan too much credit for our biological make-up. My science classes have shown me that even though it is possible not to eat animal meat to get the nutrients I require, the human body needs 20 amino acids to function properly. However, the human body only creates 10 of those essential amino acids but animal meat contains the other 10 amino acids the human body desperately needs. This makes me wonder why would God want humans (and animals) to be herbivores alone when animal meat is the best source of protein for our bodies. Why can carnivory not be the nature that God intended for an animal?

Lewis also writes that because animals fell when Satan fell, the animals began to devour each other, which caused God to instill an excessive sexual impulse into the animals to keep up with their carnivory, but why is this impulse connected with animal corruption? Did God not make humans have an impulse to reproduce as well?