All knitting through the back loop does IS twist the stitch. It's often done intentionally as a decorative stitch and sometimes it's done to tighten a stitch. As long as the stitch is removed properly the knitting won't fall apart. There is a method called 'combination knitting' that some people do in which you knit through the back loop (ktbl) and you untwist the knit on the other side by wrapping the purl under instead of over.
It's good to know the standard method of knitting though, it makes following patterns easier. It doesn't matter one bit whether you continental or English. They both work and both can be fast. It's also handy to know.