Good news for coffee drinkers: A new study shows drinking coffee or taking caffeine half an hour before aerobic exercise can increase fat-burning. The study, published in the Journal of the International Society of Sports Nutrition, shows that taking a dose of caffeine 30 minutes before an aerobic workout increased fat oxidation, exercise intensity, and maximum oxygen uptake. The researchers did find that the effects of caffeine were greater for afternoon workouts. Coffee, especially on an empty stomach, right before exercise isn’t for everyone. Remember that using it in the afternoon might interfere with your sleep that night.