You can't ever change your looks, unless you get plastic surgery on your face, so you are dealt the hand you are given.
I don't get how being attractive assumes you are smart though, I can name 100 guys/girls with pretty faces who are dumb, and 100 guys/girls who are uggo who are smart.
I guess some people say being fit means your smart, but there are THOUSANDS of dumb muscular guys and some smart fat guys.
But, being fit is SO relative. For me, I'm fit, and I have very little muscle, I only run and swim and quite thin, but stay healthy.