Is Empty Stomach Cardio Better For Fat Loss?

February 23rd, 2010 by

Does it matter if you do cardio in the am on an empty stomach? I get up at 4am and do my cardio at 6:30am so i’ve been eating my first meal of the day at 4am. Am i defeating the purpose of burning fat?

No, it does not have to be done fasted. Can it be if it’s more convenient for you? Sure. But it’s not something that must be done. That said, intervals and other high intensity modes should not be done fasted.

What matters isn’t so much where the energy is coming from (ie. fat vs glycogen), but rather, how much you’re burning (overall caloric expenditure). 300 calories is still 300 calories at the end of the day, whether it’s coming from fat or glycogen/carbohydrate. At the end of the day, it’s still helping to create a deficit.

That said, empty stomach cardio will rely on more fat to fuel the workout given the overnight fast. However, again, it’s not an issue of what fuel is being used during your cardio – it’s the overall calories burned! You don’t burn MORE calories doing exercise fasted. Add to that the fact that tuel utlization is more tied to exercise INTENSITY, not exercise timing.

These articles by Alan Aragon explain it far better than I could do justice here:

Myths Under the Microscope Part 1: The Low Intensity Fat Burning Zone
Myths Under the Microscope Part 2: False Hopes for Fasted Cardio
Myths Under the Microscope Part 3: Discussion & Afterthoughts

Take the time to give those three articles a read. There’s little argument to be made for the necessity of fasted cardio for fat loss after you’ve been through them.