Zumba is a very fun way to burn calories! Zumba Gold is actually a class for older people, or patrons with physical limitations. (At least that is what it was designed to be.) Often it is simply a Z,ba class with less impact-intensive moves.
I personally love Zumba and have become a major addict. I burn about 600 cals+ and hour, but like all exercise, your burn is only equal to your output!
Like the above posters, I watch my food intake to maintain (and to lose) and exercise is for toning, etc.
Try it out! You may love it.