As far as the difference between burning STORED fuel/fat....its negligable. But think of it this way... will eating something before you work out make you able to work for harder/longer? If so, than that equates to an overall larger caloric burn for you. On the other hand, if eating something before you work out means youl get sick and not able to finish.......
Theres all sorts of research to support both sides. Do what works for you.
Especially if you are doing any sort of strength training you need to eat EITHER before OR after your workout. Your body needs the nutrients for a proper recovery. I personally prefer the PRE workout nutrition, but many people opt for POST workout nutrition instead. Either way shoot for a balanced, high protein, high Glycemic workout nutrition....... in a perfect world, we would have both pre and post, but sometimes, especially when dealing with fat loss and caloric deficits, we just dont have anough calories for both

never underestimate the imoprtance of nutirent timing....