Interval training is a great way of burning fat, according to a study in the Journal of Applied Physiology.  It also improved the overall times of the participants 10k runs.  In the study participants did 30 sec sprints and rested for 30 sec, instead of running until exhaustion.  This cut training volume by 25%.  The theory behind this is that running at speed for long periods will cause potassium build-up in the muscles which will the cause fatigue.

Source: Journal of Applied Physiology