Is Fasted Cardio Good For You?

is fasted cardio good for you?

Fasted cardio is cardio that is done first thing in the morning on an empty stomach. So is this good for you or not? I will explain, but first we need to cover a few technical details.


Your body uses two main pathways for energy.


One is known as the anaerobic pathway, and your body uses this for high intensity exercise such as HIIT, weights and short interval training. The main fuel for this type of exercise is glycogen (which comes from carbs) and creatine phosphate.


The other pathway is known as the aerobic pathway, and your body uses this for low to moderate intensity exercise such as power walking. The main fuel for this type of exercise is glycogen and fat.

When you start any type of exercise, you will be in this aerobic / fat burning zone. As your exercise intensity increases, you will switch over to the anaerobic pathway at a certain point. The fitter you are, the longer you can stay in this fat burning zone.

When you do cardio at a low to moderate intensity, the body’s preferred fuel is glycogen (carbohydrate) first, and then fats. However, the longer you exercise, the more fat your body will burn.



So to finally answer the question – it IS beneficial to do fasted cardio. This is because you have not eaten anything for a fairly long period of time, so there is not much glycogen (carbs) stored in your body, and as a result, you will end up burning more fat. Fasted cardio works better if you haven’t had a lot of carbs to eat for dinner.

It is best to do low to moderate intensity cardio in the morning. If you tried to high intensity exercise, your body would not have as much energy for it. Therefore you would not be able to do as well during your workout. If you are fit, you would likely still burn more fat doing higher intensity fasted cardio, but it is generally not recommended.

Long, slow cardio is not the most effective way of losing weight. However it IS beneficial to lean out your legs. You will not gain muscle doing this type of exercise, but you won’t necessarily lose muscle either. Read more about how to use fasted cardio to lean out your legs here.

Find out more about my workout and nutrition program that is tailored to slim down and tone your legs here xx

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Rachael is an Australian born certified personal trainer and nutritionist who holds a Bachelor degree in Science.

After struggling for years to find an exercise and diet program that is tailored to women striving for lean and toned body with no bulk she designed her Lean Legs Program. This program is tailored to each body type and focused on helping women get toned but feminine bodies, without getting bulky.

Her mission is to empower women and help them stay in shape in a healthy and balanced way.

25 comments on “Is Fasted Cardio Good For You?”

    Vicky says:

    Hi Marina,
    Thank you for your feedback! So are you saying doing power walk after resistance training is MORE effective for fat loss than fasted power walk? Id rather choose one or the other. Thanks again! =)

      Ana - Lean Legs Support says:

      Both are totally effective! :)

      Feel free to try out both versions and you will see what works out for you better!


    Vicky says:

    Hello, i love your blog!! Thank you for sharing your knowledge :) So since carbs are used first then fat, would it be ok if I start with fasted power walk then run after? would that give me more chance to burn more fat? I know it would be tiring but I’m a beginner runner so i can only go a few mins anyway lol! Definitely hoping to be an avid runner some day.

      Marina - Lean Legs Support says:

      Hey lovely,

      If you want to speed up your fat loss process, you could try power walking after your resistance training sessions :)

      This is what Rachael usually recommends.

      Let me know if you have any other questions! xx


    Michelle says:

    Hi again,

    Will I plateau doing 10k walks 3-5 times a week? I can’t swim very well and I don’t like jogging, so walking works well for me. I know a plateau can happen with other workouts, but is LISS exempt from this or should I try to change it up somehow?

    Also, with regards to my full weekly workout routine, is it ok to do the exact same workout routines every week and change it up after 4-6 weeks to avoid a plateau? I see people talking about this on the internet and saying we need to change our exercises after a few weeks. I am am endomorph and I do the same glute work, cardio and Pilates routine twice a week and HIIT once a week and my upper body and stomach twice a week. I do the exact same routines for each area, twice a week, so that I can maximise the muscle growth where I want it and lose the fat and muscle from where I don’t want it. But instead of this, should I be doing two DIFFERENT stomach/legs/arms routines, etc, every week, instead of the exact same ones?

    Thank you

      Tijana - Lean Legs Support says:

      Hi lovely <3

      As with any exercises, after some time, if you notice that you don't get the same results, you need to spice it up a bit - this goes both for cardio and resistance exercises. You can increase the number of steps (or the time you spend walking), increase the number of repetitions or change your regime - the choice is yours (and your body's, of course) :)

      The only thing that Rachael doesn't recommend for endomorphs is HIIT - I would avoid it entirely if I were you. You can read more about recommendations for endomorphs here.

      I hope this helps! xx


    Michelle says:

    Hi Rachael,

    So glad to have finally found someone who speaks for endomorphs.

    I have started walking as my LISS, but I’m concerned about shin splints. I keep getting the pain and obviously I can’t walk when the pain is still there. Will I stop getting shin splints the more my body gets used to walking? Online it says you have to strengthen calf muscles to combat shin splints, but I was born with big calves and thighs, so I’m weary of doing that in case my calves get any bigger. Having said that, if that’s what I need to do, is there any particular exercise/stretch you can recommend that will help prevent shin splints. Obviously the least bulking, the better, especially due to the fact that I have cankles as well as big calves. 😩

    Thank you.

      Ana - Lean Legs Support says:

      Hi lovely,

      Sometimes repeating the same muscle movements over and over can cause problems like shin splints or tendinitis.
      Try walking slower if you are doing it aggressively, stretch well and have rest days!

      Your legs should get used to walking pretty soon, but if your pain is unbearable visit your doctor or specialist, just in case. :)

      Hope I helped! xx


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