Does fasted cardio burn more fat

Hi does fasted cardio eg walking for 45 minutes burn more fat??


  • bubus05
    bubus05 Posts: 121 Member
    I think one has to be careful doing any kind of exercise while being in a 'fasting state' if the fasting lasts over 24 hours. In that state you might lose more weight but the body might start burning muscle tissue. Though a low intensity training probably won't hurt you. I never noticed any difference in weight loss during a longer fasting whether I did some walking or just sat on my *kitten* all day. If what you mean is exercise during IF a shorter fasting IMHO the more you train the more fat you will burn obviously within one's limit, but you can go for it. Walking is great for fat loss though I personally prefer a higher intensity training, each to their own.
  • MaltedTea
    MaltedTea Posts: 6,286 Member
    Another "no" here. Please read the human studies.

    That said, if you personally like to train fasted then go for it! 🙌🏿
  • riffraff2112
    riffraff2112 Posts: 1,757 Member
    My records are pretty meticulous (and may not be true for others) but I noticed no difference in rate when I did cardio fasted or not. Mind you my cardio is mostly steady state, perhaps results are different at higher intensity levels?
    Personally, I just don't enjoy working out fasted, so whatever benefits might exist, would be outweighed by my lack of effort.
  • sflano1783
    sflano1783 Posts: 117 Member
    Maby yous ate carbs on your last meal from the day before cause when there's no carbs in system you start burning up fat in a fasted state
  • SnifterPug
    SnifterPug Posts: 746 Member
    I have trained fasted every morning ever since I figured out that breakfast is not the holy grail of meals for me. It doesn't seem to have made a blind bit of difference as far as losing weight is concerned, except when combined with a calorie deficit. And I credit my resistance training for keeping my muscle levels and dropping fat, not the fasted state training.
  • 33gail33
    33gail33 Posts: 1,155 Member
    I always look to peer reviewed journals for these questions - because anecdotes are usually all over the place and unreliable. This meta analysis does seem to suggest that fasted cardio does increase fat oxidation - but for the average person I'm not sure how much of an impact it would make.

    This systematic review with meta-analysis suggests that aerobic exercise at low-to-moderate intensity, performed in the fasted state, induces an increase in fat oxidation, when compared with exercise performed following consumption of a carbohydrate-containing meal. Despite high heterogeneity of the data, no difference appears to exist between exercising in the fasted or fed states in relation to variations in NEFA concentrations before and after exercise. In contrast, variation in relation to glucose and insulin concentrations appears to be higher in the fed states. Future meta-analyses and randomised clinical trials, inclusive of an evaluation of the long-term effects of aerobic exercise on fat and carbohydrate metabolism in the fasted and fed states, will be necessary to confirm the findings of the present review, as well as to identify their real benefits or consequences for long-term health."
  • MaltedTea
    MaltedTea Posts: 6,286 Member
    sijomial wrote: »
    sflano1783 wrote: »
    Maby yous ate carbs on your last meal from the day before cause when there's no carbs in system you start burning up fat in a fasted state

    No that's not how bodies work - you are burning fat 24 x 7 and completely using up of your glycogen is called hitting the wall (running, triathlon) or bonking (cycling). If you do manage that after hours of hard exercise you basically lose the ability to exercise or even think straight.
    Heard of the Brownlee brothers? This video is what using all your carbs up actually does to you.....

    Read through the responses again, it's not carbs first and then fat second. It's both fuels all of the time in varying ratios. Even people like me with high carb diets are burning fat 24 x 7.
    I don't know where you have got your ideas from but I'd suggest changing your sources of information - that this thread is remarkably consistent in the advice from many different people should tell you something.

    The video is so beautiful! I'm literally crying 😭

    And also bonking sucks! 😭
  • FitAgainBy55
    FitAgainBy55 Posts: 179 Member
    In addition to all of the other data provided here I can provide some empirical evidence that it doesn't matter in the end. I used to run Marathons and during training ran 40 - 50 miles per week. At that stage I was tracking my food intake and weight religiously. For a couple of years I ran all but my once per week long run in a morning fasted state. I then changed my routine to eat breakfast first and followed that routine for roughly 1 year. My weight and calorie intake was consistent -- bottom line your body sometimes uses fat, sometimes uses glycogen, sometimes uses muscle etc.. for fuel and at the end of the data it all works out to calories in vs calories out.
  • heybales
    heybales Posts: 18,842 Member
    sflano1783 wrote: »
    Hi does fasted cardio eg walking for 45 minutes burn more fat??

    Unless you are very unfit aerobically, and gasping for breath during that walk - your main source of fuel is probably going to be 80-85% fat anyway.

    Unless you literally just ate and insulin is still elevated in which case you burn whatever you ate for fats and carbs until insulin drops then back to normal fat burn.

    But your overall day for fuel source amounts didn't change.

    If you were doing some cardio pretty intense, the fasted state could actually have you doing it less intense compared to fed at some point before the workout - and less intense means less calorie burn overall, so less fat and carbs burned overall. Even though the ratio of fat to carbs might be a few % higher burning less calories.

    If you are that marathon trainee with hours of running you may initially benefit training the body to use better ratio of fat to carbs right from the start, so as to preserve those limited carbs, but it'll eventually learn that anyway.

    For your walk though - no.
  • lgfrie
    lgfrie Posts: 1,449 Member
    I'll throw out a semi-interesting data point here just for the hell of it. I monitor my HR every day for my 75 minute cardio workout. Normally, this is an 85-100 watt workout on an exercise bike. My HR if in a fasted state is usually 101-103. However, if I eat lunch first, it can range from 106 - 112, normally around 109. I have often wondered what the significance is, if any, or what it says about weight loss, exercise, and meal timing. My uninformed hypothesis is that it takes a bit of extra effort on top of the cardio to digest the food, hence the bump up in HR. Not sure what that means for the overall net caloric day, though - probably nothing.
  • LoveyChar
    LoveyChar Posts: 4,335 Member
    I would encourage you to do your own research on this. Many to most people will share their experiences and that's great! But it's just that...a nonmedical opinion. Research has suggested that there may be as much as a 6% increase in fat burning due to fasted cardio. Again, it's research in medical journals that could best answer your question.

    Inevitably it is eating at a deficit over time that will create weight loss. With that being said, I like fasted cardio. I will usually prefer a fasted run to any other one. Big fat however, if I were to run fasted and come home and overeat then no matter how great the run was the fasted cardio wouldn't have made a difference and would have been done in vain.

    Also and most importantly if you enjoy doing cardio fasted as opposed to not doing cardio in a fasted state, then ultimately, that is what matters most!
  • lemurcat2
    lemurcat2 Posts: 7,885 Member
    lgfrie wrote: »
    sflano1783 wrote: »
    Hi does fasted cardio eg walking for 45 minutes burn more fat??

    Not really. Big deals have been made in diet literature about small differences in fat burning processes that may exist at the very outer margins of what matters for weight loss, if they exist at all.

    If you eat 2,000 calories and do 400 cals worth of cardio, you are going to have a net of 1600 cals for the day, no matter when you eat the food and do the exercise. If it's 1595 or 1605, it isn't going to affect your weight loss in any material way.

    I prefer to do cardio fasted but I don't think it's giving me any extra weight loss.

    This. I prefer to run fasted, so do, but I walk at any time of the day and there's no reason to think walking after eating is somehow sub par.