The best type of fat burning exercise is the simple kind but don't mistake that for the easy type that you see most people doing on cardio machines.
If you really want to burn calories, fat, and boost metabolism try this bodyweight circuit instead:
skaters (lateral leaps)
Try 10-20 reps of each and repeat 5 times or better yet 30-50 seconds of each exercise with only 10 seconds rest between exercises then repeat 2-3 more times. I guarantee this will turbocharge your metabolism, blast tons of fat and calories plus tone your entire body (unlike cardio machines).
I'm filming this workout next week and many other bodyweight cardio workouts like this next month. Remember that transforming your body is all about challenging it with dynamic movement patterns that keep your workout fun and interesting too.