Hitting the treadmill or stairclimber before breakfast has long been thought to be the best way to force the body to burn more fat than carbs for fuel since you’re exercising on an empty stomach. But while it makes sense in theory, science finds the concept comes up short. One study recruited 20 active young women to perform cardio in either a fed or fasted state for one hour, three days a week, and found no greater difference in the amount of fat lost after one month between the two groups. “Your body adjusts fat utilization over time, so whether you are doing cardio in a fasted state or not, it ultimately will not make a meaningful difference for fat loss,” explains Brad Schoenfeld, Ph.D., the director of the Human Performance Lab at CUNY Lehman College in the Bronx, NY.

Bottom line: If you need a quick snack to get your workout going in the a.m., don’t be afraid to eat up. 

SEE ALSO: The Facts On Fasted Cardio