I have heard that caffeine before exercise can encourage lipolysis, but before I advise any of my clients about this, I would like to know a little about how this works and what dosage of caffeine they should take.
Research has shown that consuming caffeine about 60 minutes or so before endurance exercise may enhance fat oxidation, thus sparing glycogen. However, the disadvantages outweight the benefits of intaking large amounts of coffee. Studies have used anywhere from 300 to 500 mg of caffeine usually on a pill form (2.5 cups of percolated coffee = approximately 300 mg). The side effects would include headaches, increased heart rate and a potent diuretic effect that could be detrimental during the activity. Caffeine should definitely not be used as an ergogenic aid.