Scientists from the Department of Physiology at the University of Granada (UGR) studied 15 men, who each completed an exercise test at four different times per week.
Subjects ingested either 3 mg/kg of caffeine (the equivalent of a strong coffee) or a placebo at 8am and 5pm respectively, and fat oxidation during exercise was calculated accordingly.
Lead author of the study Dr Francisco José Amaro-Gahet says the results showed “acute caffeine ingestion 30 minutes before performing an aerobic exercise test increased maximum fat oxidation during exercise regardless of the time of day”.
The research is also deemed as important as it shows the old adage of working out on an empty stomach to increase fat burn may in fact be false.
“The recommendation to exercise on an empty stomach in the morning to increase fat oxidation is commonplace. However, this recommendation may be lacking a scientific basis, as it is unknown whether this increase is due to exercising in the morning or due to going without food for a longer period of time,” added Amaro-Gahet.
Instead, a combination of coffee and aerobic exercise performed at moderate intensity in the afternoon provides the optimal scenario for people seeking to increase fat-burning during physical exercise.