I'm kind of in the same boat, gained weight when I was laid up from wounds in Afghanistan. High intensity intervals work great for me, weight training is good too but as other have said, you have to watch what you're eating.( and I love to eat so i know) be careful running at first, can be brutal on your joints if you're running on pavement too often. Good luck to you!
Babolat AeroProDrive '12, 62lbs RPM Blast/Vs Gut hybrid