I can't help but think that you'll

up your joints and spine with hours and hours of jumping up and down like that.
Proper running technique, on the other hand, eases your body into each stride (why they teach you to roll from the heel to the ball of your foot). If you've seen how awkward and painful it looks to see someone run flatfoot, you may understand my hesitation about DDR. Try running a mile or two (start with only one if that's all you can do) each day.
The key is to develop a pattern. Make working out a habit, and that's a large majority of the problem sovled (the other large majority being diet). DON'T make excuses for yourself to skip working out, and DON'T make excuses for yourself as you why it's ok to eat food/drink item ____ on a day you shouldn't.
Plan for a cheat day. a righteous, knock down drag out gorge fest. Deny yourself for six days, and feast on the sixth. It really (1) helps the diet part, (2) helps financially, and (3) really makes shitty foods seem like rewards rather than soul-reducing compensations for low self-esteem (like

ing "Cathy" comic strips).
Best of luck to you, whatever you may choose.