Did you guess correctly? What a fool!

Also, don't let this happen to you. A new study suggests that you only need to work out for 30 minutes daily to lose weight. They key is to break a sweat.

I've been working out pretty regularly -- five or six days a week -- and have seen great results. And I was only doing it for about 30-45 minutes. However, I always drip sweat after.

Learn more about the study here.