Caffeine does not significantly burn fat, unless you’re doing a lot of intensive, long duration exercise, which can be a dangerous combination which we do not recommend for most individuals.
Caffeine has been used by endurance athletes as a performance enhancer, though its effect has been a controversial subject for several years. Caffeine works at different levels in the body to cause its effects. Studies indicate that it acts as a stimulant to the central nervous system, increases reaction time in sports requiring quick reflexes (martial arts, boxing, wrestling), and increases the utilization of free fatty acids in the bloodstream.
Research has determined that caffeine will increase endurance during such activities as long-distance running and cycling, but is not beneficial for strength-training athletes. During endurance events, the muscles use both fat and glycogen (blood sugar) as fuel. The natural tendency of our bodies is to use mostly glycogen during the first 90 minutes of running, cycling, and similar activities. After the 90 minutes, the glycogen stores become depleted, causing the body to slow down as it switches to fat as a primary fuel. Studies indicate that caffeine will increase the use of fat as fuel in place of muscle glycogen. This delaying of the use of muscle glycogen will allow a person to maintain a given pace longer before fatigue sets in. This would be especially important to anyone attempting to lose weight or body fat because he/she will be able to exercise for longer periods of time, resulting in more calories burned and an increase in basal metabolism.
The following chart can give you an idea of exactly how much caffeine you’re consuming:
Coffee, 8 oz. cup:
Regular brewed, drip method = 184 mg.
Decaffeinated, brewed = 5 mg.
Instant = 104 mg.
Tea, 8 oz. cup:
Brewed, U.S. brands = 64 mg.
Brewed, imported brands = 96 mg.
Other:
Chocolate milk, 8 oz. glass = 5 mg.
Diet Soda, 8 oz glass:
Diet Mountain Dew=55 mg
Diet Coke=45.6 mg
Diet Dr. Pepper= 41.0 mg