What is Fasted Cardio and Does it Really Work for Weight Loss?

Doing Fasted Cardio
02 Sep

Last Updated on May 21, 2023 by Michael Brockbank

Any cardio activity is exceptionally beneficial whether you’re trying to lose weight or simply want to live longer. But how good is fasted cardio when you’re trying to shed the pounds?

Today, we’ll look at a few facts and why you might want to work up a bit of a sweat first thing in the morning.

What is Cardio Exercise?

The term, “cardio,” is actually an informal derivative of “cardiovascular exercise.” It is the physical movements that result in a higher heart rate. The premise is to strengthen your heart as well as blood circulation.

Cardio activity prevents a myriad of conditions including heart disease, which kills one person every 34 seconds in the United States. Of course, a lack of exercise isn’t the only culprit for heart disease and cardiovascular issues. Foods also play a major role in these deaths.

Essentially, it comes down to efficiently using the foods you eat as energy throughout any given day. The more active you are, the more “fuel” you’ll need.

The quality of fuel you consume also plays a role, though. You can’t expect to be healthy if you maintain a 2,000-calorie diet of eating nothing but cupcakes all day.

There is a lot more that comes from cardio exercise than just burning fat. It’s also a way to increase the strength of your heart, muscle tone, improve endurance, and will affect your mental health.

What is Fasted Cardio Exercise?

Fasted cardio is the activity that you perform on an empty stomach. Perhaps the easiest method for this is to exercise first thing in the morning. This is because most people will have an empty stomach shortly after waking up.

Though, you can exercise during the day if you’re doing an intermittent fasting diet.

The idea of fasted cardio is to force your body to utilize fat stores for energy instead of carbohydrates. This means you might be a bit sluggish at first until your body gets used to the conversion.

Unfortunately, there is contrasting evidence to whether this form of exercise is viable or not. For example, in one study, there was no discernable change in body composition.

However, another study demonstrated how training in a fasted state may contribute to boosting endurance.

The bottom line is that there really isn’t enough scientific evidence to support fasted cardio one way or the other. So, it really boils down to the individual and a specific diet plan.

Benefits of Fasted Cardio

The most obvious benefit of cardio while fasting is the reduction in body fat. In one case, men who fasted while exercising saw as much as a 6.2% reduction in body fat over those who were fed.

Unfortunately, I can’t access this particular study as it is locked behind a paywall. So, take it with a grain of salt.

Still, the same principles for fasted workouts apply as they do for the Keto diet. You’re forcing your body to use fat for energy instead of consuming carbohydrates.

In fact, I’ve found that simply keeping carbs below a certain point helps me drop fat relatively quickly. But, it also depends on the quality of the food I eat that day.

Drawbacks of Fasted Cardio

Perhaps the most notable drawback of anything related to fasting (diets or exercise) is being in a catabolic state.

This is when your body will break down fat AND proteins to keep itself alive and functioning. In other words, you’ll start to lose muscle mass quicker over time.

For those who are working on creating a muscle-rich physique, fasted workouts could be ultimately counterproductive. You may still gain muscle, but it may also take much longer than someone who isn’t fasting.

Until there is more evidence available, results are pretty much up to the individual and the intensity of the workout. Remember that everyone has a unique physiology.

How to Safely Do Fasted Cardio

Performing exercises while fasted isn’t the best option for many people. For instance, women who are pregnant or those who have severe issues with hypoglycemia might want to find an alternative.

It’s always best to consult your physician before making major changes to your exercise or diet routines.

With that being said, there are some ways you can safely perform fasted cardio without putting yourself at risk.

The best way to do fasted cardio is by focusing on low-intensity steady-state cardio for 30 to 45 minutes. This includes cardio activities such as walking, a light jog, or cycling.

Even a leisurely swim in a small pool can be enough first thing in the morning. This is aside from the overall benefits of swimming.

Also, remember to keep yourself hydrated. Of course, this is true no matter what kind of workout routine you decide to perform. You run the risk of dehydration when you exert yourself in any manner.

What Has Been My Experience with Fasted Workouts?

I started doing fasted workouts by accident. I found that eating before exercising made me very nauseous. Once I removed a meal before doing cardio activity or hitting the weights, I felt a lot better overall.

However, I also found that my blood sugar dropped incredibly low extremely quickly. This meant I had to find a balance of not making myself nauseous, but making sure I wasn’t passing out.

Luckily, a lot of these problems seemed to have corrected themselves after losing 80 pounds. Although I still get a bit queasy if I eat before working out, I’m no longer plagued by hypoglycemia while exerting myself.

In any case, fasted cardio has been beneficial for me over the years.

Now, when I go to the gym, I’ll have a serving of Emerge and a protein shake. This is because I often focus on both cardio and weight training. Keep in mind, though, that this is what works best for me.

As for fat loss, I notice a big difference with fasted cardio on days that I actually stick to my diet plan. Like any other workout, it means very little if you still eat a bunch of junk in the afternoon.

So, What Does This All Mean?

The problem with a lot of health and fitness information is that there is quite a bit of contradicting evidence. Or, the sample of subjects is so absurdly small that you can’t really get a viable result anyway.

Still, there are a lot of people who seem to get something out of fasted cardio. And in the end, that’s all that really matters.

The perfect combination for dieting and exercise is whatever works best for you. I know that sounds like a cop-out, but it’s true. This is why some people love Keto while others will become vegan.

Everyone’s physiology is different enough that what works for one person, may not work for you.

This is primarily why I keep track of everything in a spreadsheet. That way, I can see the results of things I try and determine what method is the best for me.

As for fasted cardio, it’s definitely something worth trying, especially as it helps by burning fat for energy. Just don’t push yourself into a catabolic state.

Sure, the scale will say you weigh less. But that’s because you’re eliminating fat and muscle.

What kind of Cardio Exercise Do You Enjoy Most?

I’m not simply into cardio activities to burn fat. I do them to keep my heart beating as I would really like to live longer. For me, anything that works me up into a sweaty mess is ideal. Though, I’m quite partial to walking, riding, swimming, and playing the Xbox Kinect.

And yes, most of these cardio activities are done in a fasted state.

What’s your favorite cardio exercise?

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