It burns calories, and therefore fat?
Also boosts metabolism for longer post workout to burn more calories than the calories burned during the exercise?
Or is that all bollocks?
Probably not as good at burning fat as 2 hours at zone 2, but I would have thought it is slightly more time efficient.
If you want to burn fat in a few spare hours a week get a smart trainer and do some nasty intervals. HIIT and the like