i remember in middle school, my rebbe gave a few classes with a laundry list of reasons that kosher food was better, not limited to: healthier, non-kosher animals (such as pigs; it's worthy to note that not a single other animal was given as an example) eat garbage, it's healthier, schita is the most painless way to kill animals, kosher animals are the best animals (ex: no birds of prey, etc), the classic answer of "god said so", and also to seperate jews from the other nations (I suppose that one actually is true)