Fasted Cardio

Fasted Cardio It means that you have not eaten before an activity. Whoa…. that is crazy talk! You gotta have your Pops, I know.

Well, it’s not really crazy. I’m a true “For the Love of Breakfast Kind of Person,” and here to tell you that Fasted Cardio is totally possible. 

It’s typically is done in the morning because it’s hard to have a true fasted workout if it’s not first thing upon waking. Once we have our first meal we are in the process of digestion kind of all day long. Don’t we all just love to eat?

Is the goal of Fasted Cardio different from regular cardio? Sort of.

The goals here are to use fat stores for fuel instead of food in the belly. Why is that important? It means more calories from fat are going to be burned than if you had eaten before the activity.riseandshine

Can you burn more total calories with high intensity cardio activities anytime of day and still achieve the same desired end game without committing to a fasted cardio routine?

Yes, most likely. But every road looks different and each body responds differently.

Here’s the information: Do it for 1-2 weeks – See what it does for your composition. (and let’s be clear that is what we are talking about: Nothing about fasted cardio pertains to training your heart. It is about playing with energy sources.)

Let’s talk for a moment about calories so this whole thing makes a bit more sense. If you burn more calories than you take in, your body goes into caloric deficit. 

  • caloric deficit inevitably brings about weight loss as that stored fat and glycogen that you once were saving is getting used faster than you can replenish it.  

IPSO FACTO: Only 2- 3K calories of carbohydrates can be stored as glycogen in the liver and muscle. The liver and muscle glycogen are what you use when you move, particularly high intensity, anaerobically, and/or when moving heavy loads. 

HOWEVER, Even a lean person can store up to 75K cal of fat in triglycerides all over the body. Fat has no home.. she’s more of a squatter but not in the leg exercise squatter  =)

PERSPECTIVE on what calories mean for activity: A ten- minute mile burns around 130-150 calories depending on how much a person weighs.

There are four main factors that contribute to the efficacy of a Fasted Cardio:

  • Diet/Genetics (How much you eat, when you eat,etc)

  • Hormones

  • Intensity

  • Conditioning


  • Low Blood Sugar: From the 7-8 hours you were sleeping and not eating, two things were happening. Your blood sugar (glucose) dropped as well as your insulin. Your blood glucose dropped because your body needed that sugar to continue functioning: ie. breathing, organ function, all the basal metabolic needs. An average person can burn 80 calories a minute while they are sleeping. But your individual diet and level of conditioning can take you further from these averages. Some people think low blood sugar impairs cardio performance, however low blood sugar forces the body to use stored fats for energy.        


  • Low Insulin Levels: When insulin levels are very low, your body is better able to release and transport fatty acids into the mitochondria. Right about now, we are all seeing our elementary science teacher shout out, “The Powerhouse of the Cell,” but honestly what in the hell does a mitochondria have to do with fat burning? Don’t worry it’s just literally the site in the cell where we convert nutrients into energy- so everything. The Mitochondria is everything.

Hormonal Interaction:

  • Growth Hormone and insulin are antagonistic, meaning they have an inverse relationship. Growth Hormone is secreted while you sleep for muscle repair, memory consolidation and regulating growth and appetite.

Intensity: (The most important : it makes a world of a difference – Duh)

  • Lower Intensity (50 % VO2 Max) = using stored fatty acids to get to that 50%VO2 Max and then the amount decreases. 

  • Mid-Grade intensity or intervals so that your avg is (75%VO2 M) is the sweet spot for a sustained pulling and burning from fat stores.

  • Higher Intensity Exercises inhibits stored fats from being primary energy source. As the body wants to use glycogen. 


  • A trained person will have increased fat oxidation and decreased carbohydrate oxidation than an untrained individual.

Meaning as a beast who stays in beast mode, you burn more fat, more of the time. You’re also in need of more calories because there’s a good chance you’re more active than the un-trained individual and that your body composition has more muscle. 


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