Do you consider coffee to be like some of those fat burners you can buy on the Internet? Why?
Coffee is a stimulant that boosts the heart rate, provides energy (esp. if there’s sugar in the coffee), and increases alertness. I’ve also noticed how it tend to improve one’s mood, too.
If you are doing exercise, perhaps some caffeine would help to increase performance on top class athletes. It might also enable you to do a little more exercise and a little more intensively.
The only downside I can see is that it may also make you hungrier after you finish so you may actually give up any benefits from lost calories!