Hashem gave the Jewish people the special privilege to keep kashrut. Kashrut is a decree that we just do because God commanded us to; we do not understand why we are doing it. When one keeps kashrut, he only eats pure, fit, and halachically permitted food. Even when one eats non-kosher food unintentionally, the non-kosher food becomes a part of a person and has harmful effects. Hashem is making us keep kashrut because He loves us; Hashem only wants the best for us and our health.