http://www.basrutten.com/dvd/bas-rutten-mma-workout-cds-and-dvd.html#!prettyPhoto
This is my go to workout for when I'm not hitting the gym, don't feel like running, or can't find someone to roll with. Nothing complex, not gimmicky, just works. There's a few different CDs but each one is Bas calling out combinations for you to do either on a heavy bag, with a partner holding pads, or shadowboxing alone. Trust me, even with the shadowboxing you'll be tired. The all around workout cd I like because it mixes in push-ups, jumping squats, ab work, biceps, and a few other things using the rounds of striking as a rest. Each disc has a two minute and three minute round track for when you get more advanced. They all take at most 30 minutes and you will be absolutely drenched in sweat.
I didn't even copypasta that, I just like these discs a lot. You can find them on the usual internet places if you wanted to give them a spin before purchasing.
That and just start eating better. I don't follow a specific diet right now but I try not to eat shitty food very often at all, works out pretty well.