Fasted Cardio
Most people have heard that fasted cardio is one of the best ways to get in shape, drop body fat and reach a new level of leanness. But are these claims rooted in reality?
I will answer those questions in this article. First, let us discuss some of the basics of this type of cardio.
What is Fasted Cardio?
Fasted cardio refers to any aerobic workouts done without eating first.
Most people who do this type of cardio do it first thing in the morning, after an overnight fast.
Any type of cardio including walking, using an elliptical or stair climber, swimming, jogging or running done without food prior can count as fasted cardio.
Benefits
What are the benefits of fasted cardio? This type of exercise helps you oxidize more fat because your body has already burned through stored carbohydrates during the fasting period.
However, keep in mind that greater fat oxidation does not mean greater fat loss.
Maybe you do not have time to eat before your cardio workouts. In this case, doing your cardio workouts without eating first may boost your workout adherance. Some people only have time to do cardio first thing in the morning. In that case, this type of cardio may boost consistency.
Fasted cardio may also boost your mood, especially if you do it first thing in the morning.
Starting off the day with exercise can help boost mood and productivity and help set the tone for a productive day.
Despite these benefits, fasted cardio also has some drawbacks.
Disadvantages
Not eating prior to cardio can actually limit the effectiveness of your cardio workouts.
Because you will be running on low energy, you might not be able to push yourself as hard during the cardio workout.
If you cannot push yourself as hard, you won’t improve your fitness or burn as many calories during the workout. You might actually burn less fat than during a fed workout.
This type of cardio can also cause you to feel light headed or low blood sugar. It could even be unsafe for people with diabetes or hypoglycemia.
Additionally, failing to eat before exercise could also lower your focus and concentration, increasing the chances of injury.
Interestingly, cardio done in a fasted state could also increase muscle loss. Because you are working out without food in your tank, you will be more likely to burn through muscle stores than fed cardio. This means performing aerobic workouts without eating first may actually be worse for your fat loss and body composition.
Does Fasted Cardio Actually Work?
Sure, cardio done in a fasted state can work to improve your heart health and aerobic fitness, but it might not be any better than fed cardio for body composition or fitness.
According to a 2014 study in the Journal of the International Society of Sports Nutrition, body composition changes from fasted cardio are similar to those from cardio performed in a fed state. Performing aerobics in a fasted state does not improve body composition more than fed cardio.
Additionally, Febbraio et. al found no evidence of impaired fat oxidation after test subjects consumed carbs either before or during cycling workouts. Eating before the workouts did not cause the cyclists to lose less fat.
Fasting before a workout might also limit the number of calories you burn after training. Lee et. al found that eating before a workout increased post-exercise oxygen consumption and energy expenditure in ten college-age males.
Finally, Lemon and Mullin found greater nitrogen losses in those who trained in a fasted versus fed state. This suggest performing workouts while fasted may cause more muscle loss.
For the best workout results, you should eat before training. Using good nutrition before and after your workouts increases your progress.
Still, if you choose to do cardio without eating first, here are some recommendations to minimize the drawbacks.
How to Perform Fasted Cardio
If you choose to perform this type of cardio despite the numerous drawbacks, you should follow a few guidelines. First of all, you should stick to low intensity cardio like walking. You should also make sure the workouts do not require a lot of skill or coordination. This limits the risk of injury.
Secondly, you should only do short durations of cardio to limit muscle breakdown. Your fasted cardio sessions should last no longer than 30 minutes.
Thirdly, you should separate fasted cardio from weight training sessions so that you can refuel before lifting weights.
Finally, you should eat protein plus carbohydrates after this type of cardio to help replenish your muscles.
Fasted Cardio Workouts at Home
Here are some sample cardio workouts you can do at home. These workouts take less than 30 minutes to complete.
- Easy Cycling for 20 minutes
- Walking for 20 minutes
- Easy Elliptical Training for 20 minutes
- Yoga Flow for 20 minutes
These workouts also limit muscle loss and injury risk.
Final Thoughts
Despite its popularity, fasted cardio may not be ideal for most people. It limits your exercise intensity, increases the chances of muscle loss, and does not burn any more fat than fed cardio. In fact, it probably burns less fat than fed cardio.
Still, some people may find that cardio in a fasted state works best for their goals and lifestyle.
What do you think? Do you do this type of cardio or not? Let me know in the comment section below.
