Consult with your doctor first to make sure you are healthy enough. You're a pretty big guy so you want to take a stress test. After you are cleared, then training in MMA will do wonders for your health. Cardio is great but you should weight train with heavier weight to gain some muscle(assuming 330 is mostly fat) which will help you burn some fat and raise you metabolism. Training in MMA is a great cardio workout on it's own. I think with a good diet some moderate weight lifting, and MMA training should get you in shape in less than a year. Good luck.