Bleary eyed, pre-dawn bouts on the treadmill before your first meal may not sound like a ton of fun—but science is proving the practice effective.
In a study of multiple studies published in the British Journal Of Nutrition in September 2016, researchers gathered data on 27 trials that compared the metabolic effects of aerobic exercise on those in fasted and “fed” states. Based on measures of plasma concentrations of glucose and insulin in 273 adults, significantly higher fat oxidation—the technical term for “fat burning”—took place in those who were doing cardio on an empty stomach when compared to those with food in their system.
If you’re just not a morning person, you can still put these findings to good use by foregoing food a couple of hours before your workout.