You Are What You Eat:
If you eat healthy food, your body will be healthy and vice versa.
If you wanna eat all that junk food, fine, but you are what you eat.
You Shouldn't Judge a Book By Its Cover (Don’t Judge..):
Don’t judge (decide) about someone based on the way they look.
You shouldn’t judge a book by its cover. People look really different, but they all want love and happiness.
Your Guess Is As Good As Mine:
To have no idea.
I really have no clue. Your guess is as good as mine.