Waste of money. These sorts of things are just commerce. You really don't need them. I think they are often high in caffeine. Check out what's really in them at the very least before getting sucked in.
http://www.brown.edu/Student_Service...rgy_drinks.php
Even if your drink isn't exactly like one of these, i think you can bet its somewhat along the same lines. i.e. even if it is safe for use when exercising, if you need energy, you are better off getting it from real food. And the drink will no doubt likely have some other dubious substance in it.
It says there are 43 calories in advocate. You could get those from a peppermint sweet if you needed the extra glucose i.e. quick energy boost.