USING graded exercise tests in active men, scientists examined the effect of caffeine on the oxidation of fat in morning and afternoon workout sessions.
The investigators found evidence to suggest that ingesting the amount of caffeine equivalent to a strong cup of coffee 30 minutes before aerobic exercise led to increased fat burn, especially if the activity occurred in the afternoon.
Caffeine is a stimulant that occurs naturally in coffee beans, tea leaves, and cocoa beans.
Commercial energy drinks, snacks, and many other foods also have added caffeine.
Moderate consumption of this stimulant may increase alertness, cognitive function, and weight loss.
The Food and Drug Administration (FDA) recommend that healthy adults consume no more than 400 milligrams (mg)Trusted Source of caffeine a day, which is equivalent to about 4 or 5 cups of coffee.
However, some people metabolize caffeine differently and experience negative effects at lower intake levels.
A 2019 review of 21 published meta-analyses suggests that caffeine can increase exercise performance by enhancing anaerobic power, aerobic endurance, and muscle endurance and strength.
Data also show that caffeine’s positive effect on these performance markers is more pronounced during aerobic exercise sessions than during anaerobic exercise.
Despite the evidence showing that caffeine assists in exercise performance, there is limited research on whether it helps the body burn fat.
To investigate caffeine’s ability to enhance fat-burning capabilities, scientists from the Department of Physiology of the University of Granada (UGR) in Spain examined the effect of caffeine intake on the maximal fat oxidation rate (MFO) of active men during a graded exercise test.
The study took place between June and November 2019, and the results appear in the Journal of the International Society of Sports Nutrition.
The researchers recruited 15 active men with an average age of 32 years. All of these participants were nonsmokers who had no health conditions that could worsen with exercise and were taking no medications or drugs.
They also all had previous experience with endurance training and consumed less than 50 mg of caffeine a day.
In this triple-blind, placebo-controlled study, each participant completed an exercise test four times — twice in the morning and twice in the afternoon — using a bicycle ergometer.