When you’re looking to get shredded and cut body fat, it’s common knowledge that getting in cardio is the way to go, due to its ability to tap into your fat stores and start the burning process!

However, there’s another trendy player in the fat loss and cardio game: fasted cardio. 

As you can probably guess from the name, fasted cardio involves doing your cardio sessions on an empty stomach. 

Many claim that it’s a better way to tap into your fat stores, faster … but does it really work?

Here we’ll dive into fasted cardio: what it is, how it works, and whether it’s worth trying.

WHAT IS FASTED CARDIO?

The idea behind fasted cardio is simple: cardio workouts are scheduled for when your body is in a “fasted” state, which is typically before breakfast in the morning.

Cardio activities like running, biking, and HIIT workouts each require a lot of energy (aka: calories) to work your muscles and keep your heart pumping harder to circulate oxygen and nutrients throughout your body. So cardio can be a really efficient way to burn more calories, which is key for losing weight. 

Your body needs a certain number of calories every day to carry out its normal functions while you’re at rest, which is known as your basal metabolic rate (BMR). If you eat more calories than your BMR every day, your body stores that excess energy in your fat tissue, leading to more body fat. On the other hand, if you are in a caloric deficit, your body needs to burn your stored fuel to power your workouts, which can lead to weight loss. 

Your two main sources of stored energy are carbohydrates, which are stored as glycogen in your body, and fat tissue. Glycogen is the most easily accessible form of energy your body can use, and when you’re in a “fed” state and have more glycogen stores available, your body will use this fuel first before it starts to break down your fat. 

However,  when you are in a fasted state, you have less glycogen stored, so your body has to switch to burning your fat stores for energy more quickly. [*]  So, this is where you can see why many people say fasted cardio is superior for fat loss!

WHAT ARE THE BENEFITS OF FASTED CARDIO? 

• Studies are showing that it’s an efficient way to cut your body fat. There are plenty of studies to support the idea that doing your cardio in a fasted state is a good way to lose weight. One review of several studies exploring this issue found that, when comparing fasted vs. fed cardio, those who did their cardio in a fasted state showed a significant increase in how much fat they were able to burn. [*] 
• Responsible fasting can help with weight loss as well.  Fasted cardio can go hand-in-hand with intermittent fasting, which is a pattern of scheduled eating that requires an extended fasting period and a shortened eating period. You don’t need to be following intermittent fasting in order to do fasted cardio, though, since fasted cardio can be as simple as getting your workout done first thing in the morning after hours of not eating during the night. 

ARE THERE ANY DOWNSIDES TO FASTED CARDIO?

While it might be a great solution for some, fasted cardio isn’t right for everyone. If you experience symptoms from low blood sugar, you might want to save your cardio for later on in the day after you’ve had something to eat. 

It might not be the right choice for super-intense cardiovascular workouts, either. While you might burn more fat if you’re doing longer, moderate-intensity cardio workouts like biking and jogging, you’ll want to have more fuel in the tank (aka more glycogen stores) if you want to sustain the energy for more high-intensity cardio workouts like serious sessions of high-intensity interval training (HIIT).  

IS FASTED CARDIO WORTH DOING?

We’ve seen from the research that fasted cardio is definitely an efficient way to lose fat if you do it correctly. If you’re a fan of moderate-intensity cardio like running, there’s plenty of evidence that doing your exercise in a fasted state is going to get you better results and help you get to your goal weight a little sooner. 

The bottom line is that fasted cardio is worth doing if it fits with what your fitness goals are. If your primary goal is to lose weight and fat, fasted cardio is definitely worth giving a try. But if you’re also looking to maintain or build your muscle size and strength, it might serve you better to do some HIIT workouts with the proper fuel in your system instead. 

CONCLUSION 

There’s definitely plenty of evidence that fasted cardio is more than just a passing fad. If your goal is to lose some excess body fat, the science says that it’s worth trying, so go ahead and schedule those runs and bike rides first thing in the morning.