I read a book called fit for life, it claims that beef and milk require two..thats TWO different stomach acids to digest them, the two happen to cancel each other out the result is rotted food in the stomach. after it rots it can go down. It claims milk is not fit for human consumption and beef either for that matter. I like both. Any rule of thumb here, in combining different foods together. Im sure some combos are great while others are combustiable.