Coffee, green tea and other caffeinated drinks are a popular way to start the morning. Not only does it give many people a much-needed boost, but caffeine can also help when it comes to fitness. Studies show it can help people exercise harder and for longer, and even perform better. And recently, a study conducted at the University of Granada reported that consuming caffeine half an hour before aerobic exercise can actually help people burn fat.
In the study, 15 men (aged around 32) ingested caffeine powder (about 3mg per kilogram of body mass – the equivalent of a tall brewed filter coffee) or a placebo 30 minutes before exercising. The participants then completed a total of four trials. They alternated between exercising at either 8am or 5pm on separate days. The study used a “triple-blind” experimental design – meaning that the participants, researchers and statistician did not know who had consumed caffeine or not during each trial.
To ensure the participants were exposed to the same conditions as each other, the researchers made sure it had been at least three hours since their last meal before the caffeine or placebo was ingested. No exercise had been performed for 24 hours before the trial. Each participant consumed the same diet the day of each trial.
During the trials, the participants cycled at increasingly higher intensities to determine peak fat oxidation (the process of breaking down fat to produce energy – “fat burning”). The researchers found that compared with the placebo group, consuming caffeine led to more fat being burned during exercise.
Fat burning after caffeine was up to 11% more in the morning, and 29% more in the afternoon. The greater fat burning in the afternoon could be explained by the higher concentration of adrenaline in our bodies which happens as a response to afternoon exercise. But before you get too excited, even with the higher afternoon rate of 0.4 grams of fat burned per minute, in order to lose 1kg of body fat, one would have to exercise for nearly 42 hours.