What About Fasted Cardio?


When you do your cardio is really a matter of available time. For many people, that’s first thing in the morning. This leads to the question, what about fasted cardio? If you’re doing your session right after you wake up, is it best to eat something first, or just jump right in? What about being in a state of positive protein balance? We will answer these questions and more in this article.

Types Of Cardio

Regardless of the specific machine or exercise you do, there are two primary types of cardio: steady-state and HIIT. Let’s look at each.

Steady State - This is performing the cardio exercise of your choice for a predetermined time period. A good example is jogging on a treadmill for 20 minutes using the same speed and resistance level.

HIIT (High-Intensity Interval Training) - This involves doing intervals of short bursts of high-intensity cardio followed by even shorter “rest” periods. 

Example HIIT Session

Usually in a HIIT routine, you are aiming for a set time, say 20 minutes. Since you are using high-intensity bursts, you may have to work up to your time goal. 

  • After warm-ups, perform your choice of cardio exercise, let’s say the treadmill. Sprint for 20 seconds. 
  • Walk moderately for ten seconds 
  • Repeat until you’ve reached your time goal. 

If you aren’t used to sprinting, you may only be able to do 5 minutes, adding time every session until you reach your time goal. 

The Difference Between Fed Cardio And Fasted Cardio

Fed cardio is as you might think, cardio performed not long after eating. You can do fed cardio anytime, which means you may have already eaten 3-4  times. An example would be doing your cardio session 2 hours after dinner. 

In contrast, fasted cardio is performed on an empty stomach, usually not long after waking up in the morning. 

Fasted Cardio Benefits

  • Convenient - No doubt it’s convenient to get your cardio out of the way first thing. Get it done and get on with your day.
  • May Support Greater Fat Loss - The thinking here is that in the morning after sleeping for 7-10 hours, you’ve basically “fasted” since your last meal. This suggests that your body won’t have much glycogen for energy. It will therefore use stored fat for energy. (1, 2)
  • Works Well With Intermittent Fasting - If you follow an intermittent fasting program, doing your cardio during this period may promote greater fat loss. (3)

Have A Serving Of Protein First!

The major drawback of fasted cardio is that you’re doing it in the morning, likely before ingesting anything. That means you have eaten anything since before you went to sleep, maybe 7-10 hours ago. This puts you in a catabolic state by the time you wake up. Logically, if you do 30 minutes of fasted cardio, you’re risking muscle protein breakdown. Of course, that’s not a good thing to any bodybuilder or other athlete. 

There are a few solutions. First, you could have a small protein serving before your cardio. With 26g of protein per serving, Shake Time is great for this. Drink your Shake Time about 30 minutes beforehand to avoid any nausea. Another option is to sip a serving of All Day You May Caffeinated or All Day You Shred while you’re doing your cardio. Finally, drink a serving of Shake Time an hour or so before bed, followed up with Drink Sleep Grow right before bed. This will significantly limit the time your body is in a catabolic state. In fact, potential catabolic exposure will depend on how long you sleep. For example, sleeping 5-6 hours, not so much, 8-10 hours, most likely. 

The best solution is to use a combination of these strategies to avoid catabolism and optimize protein synthesis during the night. Further, protein or the ADYM of your choice during your cardio session guarantees you stay in a metabolically positive state. 

5% Nutrition Always Has The Answer!

It’s clear that 5% Nutrition has what you need for your physique. No wonder what you’re trying to achieve, 5% has supplements that fit. In this case, besides the protein sources we talked about, you can use any of our weight loss supplements to help speed up the process of weight loss. These products include Shred Time, All Day You Shred, and Liquid L-Carnitine 3150. Got a show coming up? Be sure to add Stage Ready diuretic to your program. 


Cardio is one key to looking your best. Ultimately, the approach you take is your choice. Regardless, you can avoid catabolism, hang on to your hard-earned mass, and take big steps  toward achieving the chiseled physique of your dreams by following the tips presented here. 5% Nutrition always has your back!


  1. (PDF) Fasted Versus Nonfasted Aerobic Exercise on Body Composition: Considerations for Physique Athletes (researchgate.net)
  2. Vieira, A., Costa, R., Macedo, R., Coconcelli, L., & Kruel, L. (2016). Effects of aerobic exercise performed in fasted v. fed state on fat and carbohydrate metabolism in adults: A systematic review and meta-analysis. British Journal of Nutrition, 116(7), 1153-1164. doi:10.1017/S0007114516003160
  3. Welton, S., Minty, R., O'Driscoll, T., Willms, H., Poirier, D., Madden, S., & Kelly, L. (2020). Intermittent fasting and weight loss: Systematic review. Canadian family physician Medecin de famille canadien, 66(2), 117–125.
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