The 5:2 diet is really awesome, it's super easy to get good results from it if you stick to it, have a read about it online.
You basically eat 500 calories two days a week, the rest of the week you still need to be healthy but don't need to be as strict.
So what I do is, on Tuesdays and Thursdays I'll eat nothing all day, then around 5-6pm I'll have a meal of about 400-500 calories. It isn't actually as difficult as you'd expect. I have lost quite a lot of weight from doing this, as have many of my friends in the past.
As for fitness, HIT is a good form of exercise for loosing weight and getting fit, have a read up about this online too.
