A study suggests that taking caffeine supplements may promote weight loss in people who exercise.

In the study, 14 recreationally active subjects with a mean body mass index of 22.7 kg/m2 completed a resting control trial, a placebo exercise trial and a caffeine supplemented exercise trial.  Caffeine was used twice a day and 3 mg/kg a time 90 minutes before and 30 minutes after exercise. Trials lasted four hours with one hour of resting, one hour of cycling at about 65% power at VO2max or rest and two hours of recovering.  Two hours after exercise, subjects were offered a meal and allowed to eat ad libitum.

Exercise together with caffeine supplementation caused significantly greater energy expenditure and fat oxidation, compared to exercise only and control.  Caffeine supplementation along with exercise also cut energy and fat intake. (David Liu, PHD)

Schubert MM, Hall S, Leveritt M, Grant G, Sabapathy S, Desbrow B.  Caffeine consumption around an exercise bout: effects on energy expenditure, energy intake, and exercise enjoyment.  J Appl Physiol (1985). 2014 Aug 14.