Is Fasted Cardio Really Optimal for Fat Burning?

Tired of sifting through conflicting information about fasted cardio and its impact on fat burning? I see you. Let’s unravel the truth behind this popular fitness trend and separate fact from fiction.

Cardio is a factor my clients want to know about 110% of the time.

Should I be doing more cardio?
What’s better for fat loss on the machines: the cardio zone or the fat loss zone?
When should I do cardio: morning or night?
Before or after strength training?
Long run or HIIT?
Fasted cardio?!

Fasted cardio, the practice of exercising on an empty stomach, has gained significant attention for its potential to enhance fat burning. Some swear by its effectiveness. Others dismiss it as hype. So, what’s the truth? Is fasted cardio really the key to unlocking optimal fat burning? We will delve into the scientific research, expert opinions, and practical tips to help you make an informed decision. Whether you’re a fitness enthusiast or someone looking to shed those stubborn pounds, this article will provide you with valuable insights and guidance to maximize your fat burning potential.

What is fasted cardio?

Fasted cardio is a form of exercise performed in a fasted state (when you haven’t eaten in 10-12 hours), typically in the morning before breakfast. It involves engaging in cardiovascular activities such as running, cycling, or swimming on an empty stomach.

The idea behind fasted cardio is that when you exercising in a fasted state, your body will have depleted its glycogen stores and will turn to stored fat as its primary source of fuel. Supporters of fasted cardio believe that this can lead to greater fat burning and improved body composition. However, it is important to understand how fasted cardio actually works, the upsides and the downsides, before you decide if fasted cardio is right for you.

Fasted cardio gained popularity due to the belief that exercising in a fasted state would optimize fat burning. The theory goes that without any readily available carbohydrates to burn, the body would be forced to use stored fat as fuel. However, the reality is a bit more complex. While it is true that fasted cardio can increase fat oxidation during exercise, the overall impact on fat loss is influenced by various factors such as diet, intensity of exercise, and individual physiology.

How does it work?

During a typical workout, your body uses a combination of carbohydrates and fat to fuel your muscles. However, when you haven’t eaten for several hours, your glycogen stores are depleted, and your body turns to fat as its primary energy source. This can lead to increased fat oxidation during exercise, which is why fasted cardio is often touted as a fat-burning powerhouse.

In addition to the potential increase in fat burning during exercise, fasted cardio may also have long-term effects on your metabolism. Some studies suggest that performing cardio on an empty stomach can increase insulin sensitivity, which means your body is better able to utilize carbohydrates and store less fat. This can have positive implications for overall body composition and weight management.

Considerations – good and not so good – of fasted cardio

I should be up front: when it comes to optimizing fat loss, cardio is not at the top of the list. More on that to come but if you’re less interested specifically in fasted cardio and more interested in general fat loss strategies…

Fasted cardio offers several potential benefits beyond fat burning. But they come with caveats. While these benefits are appealing, it’s important to consider the potential drawbacks and individual factors before jumping into a fasted cardio routine. Here are some of considerations:

1. Potential for increased fat oxidation: Exercising in a fasted state may enhance the body’s ability to burn fat as fuel, potentially leading to greater fat loss over time.

However, your body does not discriminate where it pulls that fuel from. It could break down fat tissue for energy. Or it could break down muscle tissue. Muscle is a metabolically active tissue. Your body spends more calories maintaining muscle than it does other tissue. A decrease in lean muscle mass means a decrease in metabolism.

2. Improved insulin sensitivity: Fasted cardio has been shown to increase insulin sensitivity, which can help regulate blood sugar levels and prevent insulin resistance.

But fasted cardio increases other hormones too, namely cortisol. Cortisol is a hormone which is responsible for regulating stress. Chronically elevated cortisol levels can have negative implications for muscle growth and overall well-being.

3. Convenience: Performing cardio in the morning before breakfast can be convenient for those who prefer to get their workout out of the way early in the day. Beware, though. What is convenient isn’t always optimal.

Think about it this way:

Scenario 1: you’re well-fueled – 2 balanced meals and 2 bottles of water in. You’re focused and energized. Because you feel so good you push yourself to 100% effort. You run 2 miles with intervals at an average of 10 miles per hour. You burn 250 calories. Some of that energy is from fat, some of that is from carbohydrates. Very little of it is from muscle tissue. Plus, you hit it hard so your body will continue to burn more calories (EPOC) after you head home.

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Scenario 2: you’re headed to the gym in the morning on a fasted stomach. You feel sluggish because you haven’t eaten since last night. 2 miles of anything feels like a chose so you hope on the elliptical and kind of just get through it. You finish up having burned 150 calories. Some of that energy is from fat. Some of it is probably from muscle. It wasn’t an inspiring workout and you didn’t work hard enough for your body to need anymore recovery time. You still feel drained.

Exercising on an empty stomach may lead to decreased energy levels and performance. Low fuel levels do that. If you find that your workouts suffer as a result of fasted cardio, it may be more beneficial to consume a light meal or snack before exercising.

4. Mental clarity: Some individuals report feeling more mentally focused and alert after fasted cardio workouts, possibly due to increased blood flow to the brain.

Keep in mind that the response to fasted cardio can vary among individuals. Some people may thrive on fasted workouts, while others may experience negative effects such as low energy levels or muscle breakdown.

Common myths about fasted cardio

Like any popular fitness trend, fasted cardio has its fair share of myths and misconceptions. Let’s debunk some of the common myths surrounding fasted cardio to separate fact from fiction:

Myth 1: it’s the only way to burn fat effectively.

While fasted cardio can be an effective fat-burning strategy, it is not the only way to achieve fat loss. The overall calorie balance, diet quality, and exercise intensity are equally important factors to consider.

If you’ve been around JHF for a while, you know that cardio in any form isn’t my first choice for optimal or effective fat loss. For that, my heart belongs to strength training.

Myth 2: it’s suitable for everyone.

Fasted cardio may not be suitable for everyone, especially individuals with certain medical conditions or those who experience dizziness or low blood sugar when exercising on an empty stomach. It’s important to listen to your body and consult with a healthcare professional before starting a new exercise regimen.

To help decide whether or not fasted cardio is right for you, consider you’re current fitness level and health conditions. What’s your goal? Most importantly, what do you enjoy doing?

Myth 3: it means fast results, guaranteed.

While this strategy can be an effective tool for fat burning, it does not guarantee results on its own. Consistency, proper nutrition, and a well-rounded exercise routine are essential for long-term success.

Tips for optimizing your fasted cardio workouts

If you do decide to take fasted cardio for a spin (I’m sorry I cannot help myself when it comes to making fitness puns) here are some tips to help you optimize your workouts and maximize fat burning:

1. Stay hydrated: even though you’re exercising on an empty stomach, it’s crucial to stay hydrated. Drink water before, during, and after your fasted cardio workouts to ensure proper hydration and performance.

2. Start gradually: if you’re new to fasted cardio, start gradually by incorporating shorter sessions and gradually increasing the duration and intensity over time. This allows your body to adapt and reduces the risk of overexertion.

3. Listen to your body: pay attention to how you feel during your workouts. If you experience dizziness, lightheadedness, or any other discomfort, it’s important to stop and refuel.

4. Fuel properly after your workout: while fasted cardio can be an effective fat-burning strategy, it’s essential to refuel your body with a balanced meal or snack after your workout to aid in recovery and muscle repair.

Examples of effective fasted cardio workouts

Interested in giving it a shot? Here are a few examples of effective workouts to try:

• Brisk morning walk: start with a 30-minute brisk walk in the morning before breakfast. Focus on maintaining a steady pace and incorporating inclines or stairs for an added challenge.
• Cycling session: hop on your stationary bike, find an early morning spin class or hit the road for a 45-minute cycling session. Keep your intensity moderate to high and vary the resistance or terrain for a more challenging workout.
• Interval running: warm up with a 5-minute jog, then alternate between 1 minute of sprinting and 1 minute of jogging for a total of 20 minutes. Finish with a 5-minute cool-down jog.

Remember to adjust the duration and intensity of these workouts based on your fitness level and individual preferences.

Conclusion

While this can be an effective strategy for fat burning, but it’s important to understand the science behind it and consider individual factors. While fasted cardio may increase fat oxidation during exercise, the overall impact on fat loss is influenced by various factors such as diet, intensity of exercise, and individual physiology. Combining fasted cardio with other fat-burning strategies such as resistance training, HIIT, and a balanced diet can maximize your results. Remember to listen to your body, monitor your progress, and make adjustments as needed. With the right approach, fasted cardio can be a valuable tool in your fitness journey towards optimal fat burning and body composition.

If you’re thinking you might want a little bit of extra help figuring how to make all of this work for your goals, in your life specifically, hit me up – that’s exactly what I’m here for!