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Work it Out Wednesday: Fasted Cardio


Last week we talked about some good options to eat before a workout.

This week I want to talk about when it might be a good idea not to eat before a workout.

The school of thought on this topic seems to be divided.

In fact, some would call not eating before a workout stupid, while others call it fasted cardio. Haha

Today I want to dive into what fasted cardio is, as well as why it might or might not be right for you.

Keeping in mind I am just a regular gal. I love, love, love fitness and have done plenty of reading and research, but am not certified and by no means an expert. Today’s post is based on my own research and experiences.

Okay, now that the disclaimer is out of the way, let’s go!

What is Fasted Cardio?


The idea behind fasted cardio is that by performing low/moderate intensity cardio in a fasted state before you eat in the morning, you can burn more calories and a greater percentage of fat. This can lead to superior overall fat loss compared to eating beforehand.


Sooo, here are a few reasons fasted cardio might be a good idea.

As mentioned, there’s a school of thought that argues the enhanced fat burning effect behind this technique.

Some believe when cardio is done in a fasted state first thing in the morning, you will have a greater ability to tap into those stubborn fat stores on your body, which include the hips and thighs for women as well as the abs and lower backs for men (

As you might know (I sure do!), these areas of the body can be painstaking in giving up their fat stores and are why these are generally the very last places that you’ll lose fat.


In fact the British Journal of Nutrition found when subjects performed fasted cardio in the morning, they burned 20% more fat than when they had a meal before the cardio.

Similarly, a study published by the Institute of Food Nutrition and Human Health in New Zealand performed a four week test to determine the adaptations to endurance training, comparing those fed carbs before training compared to those coming out of an overnight fasted period.

Results showed the men responded better to the fasted protocol than did the women, however both fasted men and women showed a greater increase in overall VO2 measurements as well as muscle glycogen concentrations.

Bodybuilder and doctor Jim Stoppani, also notes benefits to performing fasted cardio during certain periods of training.

He argues while you sleep, your body conserves carb stores because glucose is the primary fuel for the nervous system ( Sooo during the night, our bodies move toward burning more fat, however, it also moves toward breaking down more muscle protein and converting the amino acids into glucose for fuel (

So when you perform fasted morning cardio, our bodies are forced to burn more fat for fuel. But it is can also mean burning muscle.

Which leads me to some of the cons

Fasted cardio does not guarantee you’re going to be sporting that bikini next week. Keep in mind, diet is so important to fat loss.

If you go into the gym and burn 350 calories from that fasted cardio, but then you go and eat 350 more calories that day than what you’ve burned off over the entire 24-hour period, you are no further ahead. You might burn more fat, but it doesn’t necessarily guarantee a net fat loss.

Another con really depends on your goals.

If you’re looking to build muscle mass, fasted cardio could be a bad idea.

Not only that, but there are probably better exercise options.

For example, high intensity interval training and weight lifting help burn more calories and fat after the workout is over for the rest of the day while you do nothing.

That’s a huge plus for fat loss.

Some studies show HIIT workouts that take less than 50% of the time as slow and steady cardio workouts, and can lead to as much as twice the fat loss as the slow and steady cardio programs.

Something to think about.

Even though you might burn some more calories and fat during low intensity fasted cardio, chance are you’re going to have better results and more fat loss with high intensity cardio programs.

Things to Remember

So there’s definitely some pros and cons to consider, and it really comes down to your current training program and goals.

If you’re going to give fasted cardio a go, I would say (and many reputable sites and fitness experts also say) supplement with a BCAA powder or pill before you hit the gym. That way you can help prevent muscle mass loss. Not only that, but it could be beneficial to sip a protein shake before you start working out.

Do I Perform Fasted Cardio?
I definitely do.


The morning after a cheat meal, you can usually bet I’ll be doing some fasted cardio. 

In my personal experience, I’ve found that helps to burn off the junk from the night before and alleviate any “food baby” remnants.  I always do fasted cardio with a BCAA drink.


With that said, I tend to agree HIIT training is where it’s at for maximum long-term results.

Bottom line, it might be a good option for you occasionally depending on your goals.

And now that this post is over? I’m totally craving a banana and peanut butter.


Go figure.

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brittny I'm B-Love. Lover of God, my husband Will, my doggies, OU football, weight training, plyometrics healthy eating (mostly!), peanut butter, and all things health related. Buckle up and get ready for my constant embarrassing moments, health and fitness tips,and my effort to rely on Christ while living life in the real world. Follow me on Feedly! Sign up for monthly emails at!

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