The relationship between caffeine and exercise is a strange one. You may have heard a range of confusing advice about the merits of this pairing — that your morning brew dehydrates you before a workout, that caffeine boosts your performance, and a whole host of spurious claims and anecdotes in between.
But there is some evidence to support the claim that caffeine before a workout does actually help with fat-burning — technically called “fat oxidation” — and that the time of day you drink your cup matters, too.
A study out in the Journal of the International Society of Sports Nutrition found that in a small group of active men aged 32 years old on average, imbibing caffeine 30 minutes before a workout boosted their “maximal fat oxidation” during workouts. The study also suggests the effects of caffeine on exercise were greatest if taken during the afternoon or early evening.
Excerpted from Inverse