Not eating and training is not recommended. Not all people are the same. Find out what body type you are (mesomorpth, ectomorpth or endomorth) first. This will give you an indication of how hard you have to train to loose fat.

I find the best way is to do HIIT in the morning after having a protein shake and eating smaller meals throughout the day (Ideally 5 meals a day). Believe it or not eating more does makes you burn fat!