This is a great article about how we're pretty bad at guessing how much oversized soda cups actually hold. Mayor Bloomberg is right when he asks you think twice before you buy the BIG drink. And don't forget your body doesn't register liquid calories like it does solid food so it won't recognise that you've just had a huge feed and signal you to stop. It'll do the opposite and you'll eat, eat, eat.
Take the quiz and see how good you are at guessing how much is in each cup. I got none right. I way underestimated each one.