The laws of what animals, birds and fish are permitted are given this week as part of the Book of Vayikra which deals with issue of personal purity. Purity in Biblical Hebrew has nothing to do with cleanliness as we understand it. Quite the contrary, no matter how clean a person might be, certain actions and states placed them in a category of what we would call secularism. And the contrary state would be what we call spirituality.
But after all the chapters about priesthood and their purity, the Torah expands it to include all of Israel as a Kingdom of priests. We are not expected to take all the restrictions and limitations of the priesthood. But at least at a simple level of eating, an activity we all must do, we are invited to add a dimension of holiness.
It is common to hear people say, “You are what you eat.” So, if you are a carnivore, this is supposed to say something about your character. If that were so, Hitler who was a vegetarian, must have been a very spiritual man! But there are some Jews who believe that if you eat forbidden foods, this degrades your body. This is illogical. First of all, we see that you can be perfectly healthy physically on a diet of forbidden foods. Secondly you can make yourself sick purely by eating kosher food if you eat too much or do not have a balanced diet. Meat and wine like many foods have therapeutic qualities but they also carry within them the possibility of gluttony, alcoholism and hardening the arteries. And by over indulging, sickness and disease.
Really the issue is not WHAT you eat but HOW you eat. Do you control, discipline your intake or do you simply indulge? Animals eat and excrete. Human animals do too. But what makes a person rise to a higher level is HOW he or she eats and whether they think before they eat and exercise thought and self-control. And this according to Maimonides is what lies behind the laws in the Torah, governing food.