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Bakersfield Woman doing Cardio

Article Author: Jerry Teixeira

Jerry Teixeira Bakersfield Sports Nutrition

Is Fasted Cardio Best for Fat Loss?


      This is one of the questions that clients ask most often, and it is an excellent question to address due to the fact that (like most questions pertaining to fitness) there is so much conflicting information out there.  

To make matters worse, the answer can be either yes it is better than, or no, it is not better than cardio in a fed state depending upon who is doing the cardio.  

So which is it for you? Is Fasted Cardio best for you, or should you eat?  Read on to find out…

Bakersfield Woman doing Cardio
Image Credit: Viktor Hanacek

    In order to see who fasted cardio works best for, we first need to have a small biology lesson. (oh boy!)  

To keep this as simple as possible, let’s look at what has to happen for the body to burn fat…

The 3 things that need to happen in order to “burn” fat:  

First, fat (specifically fatty acids) need to be mobilized ( released from  the fat cell ).  

Second,  fat needs to be transported.

Third, once transported, fatty acids are then burned (oxidized)

All cardio that is done will increase all three of these prerequisites for fat loss, however recent studies have shown that:

  1. Fatty acid oxidation (actual fat “burning”) is highest after 6 or more hours of fasting.
  2. Even small elevations in insulin pre exercise appeared to limit fat oxidation during exercise
  3. Endurance training done in a fasted state leads to metabolic adaptations to increase energy production from fat oxidation ( your body gets better at using fat for fuel)


As we can see, cardio done in a fasted state provides an ideal environment for fat burning, but beyond that it has also been shown to increase fat burning in hard to  reach “stubborn” areas (think lower back and Abdominals for men, hips, thighs and butt for women)  

Fat loss is difficult in stubborn areas partly because these areas suffer from poor blood flow, and lack of blood flow means lack of fat burning hormones getting into the fat cells in these areas.

Fasted cardio has been shown to increase the flow of blood to these “stubborn” areas and therefore is great for helping an individual target the last 10 to 15 pounds of fat loss that often seems so elusive.


Based on what we have learned so far, fasted cardio may seem like the way to go for everyone all the time, but there are a few things to consider first.


Thing 1.) some people suffer from lack of energy and ultimately, training intensity when training in a fasted state.  Any benefit that you would get in terms of fat loss from a fasted state may be negated by the lower number of calories burned from performing cardio with less intensity than you would have in a fed state

Thing 2.) Duration of cardio.  Fasted cardio for a prolonged period may produce an environment where you are actually losing lean tissue.  Gains in muscle do not come easy, so lean mass preservation is very important, especially because muscle is quite active metabolically and the more muscle you carry the better your metabolism will be.  

Thing 3.) What is your current bodyfat level?  Fasted cardio will have the biggest benefit over cardio in a fed state for people who are at the lower end of the bodyfat spectrum and are trying to lose “stubborn” fat.  ( the last 10 to 15 lbs or less sub 12 to 15 %bodyfat for guys and sub 16 to 18 percent for girls)


Takeaway: The most important factor to consider when assessing whether to do your cardio fasted or not is this- The most important cardio is the cardio you will actually do consistently.  If the only time you are fasted is when you first wake up and  you can’t get the cardio in at that point, just do it at whatever time your schedule permits.

However, if you are looking to burn that last 15 pounds or less, fasted cardio is likely the ticket.  Just be sure that your cardio is truly fasted (no food for 6 or more hours pre cardio).

So the next question you may be asking yourself is: “What exactly is the best type of cardio to do in a fasted state?”  I will answer that next week.  

What other questions do you have about cardio? Post your questions and comments below, I will answer every one of them.