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Fasted cardio

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Replies

  • yarwell
    yarwell Posts: 10,477 Member
    zcb94 wrote: »
    However, I've accidentally performed cardio with nothing at all on my stomach before, so was just wondering about the safety and effectiveness of doing so.

    We have fat and glycogen reserves to provide energy for fasted exercise or activity - perhaps "work" or running away from predators, etc. I can't see a safety concern.
  • yesimpson
    yesimpson Posts: 1,372 Member
    I love running first thing on an empty stomach but I doubt it has any extra benefits with regards to fitness or weight.
  • mrcs_jolly
    mrcs_jolly Posts: 25 Member
    I do fasted cardio regularly...every morning before I go into the office. It works! I lost 120lbs and fasted cardio is a significant part of my process, along with diet.
  • rileysowner
    rileysowner Posts: 8,050 Member
    zcb94 wrote: »
    zcb94 wrote: »
    Hm. I'm told that fasted exercise brings more results than having eaten, but that makes me wonder: many proponents say that there is to be nothing on your stomach at the time. That would be NPO cardio, which sounds very dangerous. I would at least need to bring some water with me! Any and all thoughts are welcome.

    Studies would not hold that fasted exercise makes any statistically significant difference. Alan Aragon wrote this about it: http://alanaragon.com/myths-under-the-microscope-part-2-false-hopes-for-fasted-cardio.html

    Not sure what NPO cardio means. Could you define it?
    As you may know, NPO is Latin for "Nothing By Mouth," a state that is usually saved for surgery due to anesthesia needs. However, I've accidentally performed cardio with nothing at all on my stomach before, so was just wondering about the safety and effectiveness of doing so.

    Seeing as a person's last meal takes approximately 8 hours to digest, and the carbs go to first replenishing glycogen stores in the muscles and liver, even not eating in the morning and doing cardio, there is lots of energy available not even considering fat stores. I know of no danger in doing so. In terms of effectiveness, you would need to define what you mean by that?
  • sunnybeaches105
    sunnybeaches105 Posts: 2,831 Member
    The real question is how much woo one can cram into a day
  • stealthq
    stealthq Posts: 4,298 Member
    edited April 2016
    Exercise fasted if it's your preference or if you're training for an endurance sport and need to train to use fat stores preferentially. Otherwise, don't. It won't make a difference for weight loss.

    Keep in mind that while increasing fat oxidation initially is increased, utilizing glycogen means you have to expend energy and building blocks (glucose & tyrosine) to replenish those stores. Glycogen stores, unlike fat stores, are replenished even in a deficit. In the end, it's a wash.

    You can think of it a bit like no-fee, savings-backed checking accounts. Let's say you have $55 in savings (fat), and $5 in checking (glycogen). Two scenarios:

    1) You need $10 and take it out of savings leaving you $45 in savings, and $5 in checking.

    2) You need $10 and take it out of checking. You're overdrawn by $5 and the bank takes $5 from savings to compensate, leaving you $50 in savings, and $0 in checking. But, the bank requires you to have $5 minimum in checking at all times. So, it additionally moves $5 from savings to checking to meet the requirement. You're left with $45 in savings, and $5 in checking just like scenario 1).
  • eyeshinebright
    eyeshinebright Posts: 51 Member
    AlphaCajun wrote: »
    I wake up at around 7 or 7:30 each morning and I often haven't eaten since 6 or 7 the night before. Because of this, I'll wake up pretty hungry and it would hurt to do cardio on a hungry stomach. Breakfast is pretty important for weight loss imo and prolonging when you have it might not be a good thing.

    I'm down nearly 90 pounds and within five of my goal in a little over a year and have yet to eat breakfast before working out.. js

    It depends on the person, but as I was trying to say, a person like me who is hungry as soon as I wake up and saw more results by eating breakfast consistently at the top of the day, then fasted cardio may not work for them. But yeah, if you're ready to go in the morning and feel like you won't faint, by all means knock yourself out.
  • yarwell
    yarwell Posts: 10,477 Member
    stealthq wrote: »
    You can think of it a bit like no-fee, savings-backed checking accounts. Let's say you have $55 in savings (fat), and $5 in checking (glycogen). Two scenarios:

    1) You need $10 and take it out of savings leaving you $45 in savings, and $5 in checking.

    2) You need $10 and take it out of checking. You're overdrawn by $5 and the bank takes $5 from savings to compensate, leaving you $50 in savings, and $0 in checking. But, the bank requires you to have $5 minimum in checking at all times. So, it additionally moves $5 from savings to checking to meet the requirement. You're left with $45 in savings, and $5 in checking just like scenario 1).

    Except when you pay in $10 (eat) and the the overdraft and minimum are replenished from what you pay in, leaving $55 in savings and $5 in checking, which was approximately what the study I linked to demonstrated.

    Scenario 1) would be $45 in savings and $15 in checking after eating. Potentially :-)
  • scottarsenault461
    scottarsenault461 Posts: 2 Member
    Thanks for all the advice much appreciated
  • Serah87
    Serah87 Posts: 5,481 Member
    mkakids wrote: »
    I do almost all of my cardio fasted. Simply because I feel better while running if Im 'empty'. If I eat before I run, I feel sluggish and heavy, regardless of what I eat.

    Me also. ^^^
  • stealthq
    stealthq Posts: 4,298 Member
    yarwell wrote: »
    stealthq wrote: »
    You can think of it a bit like no-fee, savings-backed checking accounts. Let's say you have $55 in savings (fat), and $5 in checking (glycogen). Two scenarios:

    1) You need $10 and take it out of savings leaving you $45 in savings, and $5 in checking.

    2) You need $10 and take it out of checking. You're overdrawn by $5 and the bank takes $5 from savings to compensate, leaving you $50 in savings, and $0 in checking. But, the bank requires you to have $5 minimum in checking at all times. So, it additionally moves $5 from savings to checking to meet the requirement. You're left with $45 in savings, and $5 in checking just like scenario 1).

    Except when you pay in $10 (eat) and the the overdraft and minimum are replenished from what you pay in, leaving $55 in savings and $5 in checking, which was approximately what the study I linked to demonstrated.

    Scenario 1) would be $45 in savings and $15 in checking after eating. Potentially :-)

    Well, if you want to get precise about it, replenishing glycogen stores in a deficit takes a while - up to 48 hrs depending on intake. And the minimum $5 in checking would really be coming from the pay in and not from the bank moving money from savings to checking. Fat doesn't get utilized to create glycogen, after all - it just covers for the energy that would have been available if glycogen didn't need replenishment (glycogen synthesis & potential energy in the glucose and tyrosine). I was trying to simplify by skipping the re-feed portion of the scenarios.

    Again, on the time scale OP is talking about, it's a wash.
  • abtriboy
    abtriboy Posts: 144 Member
    I prefer fasted. Workout feels better. As long as no too dpletes
  • Azdak
    Azdak Posts: 8,281 Member
    yarwell wrote: »
    Doesn't matter. Keep eating at a deficit it will come off. There is no benefit to fasted vs non fasted. CO is CO be it in the morning, afternoon or evening.

    http://jap.physiology.org/content/jap/118/1/80.full.pdf expresses a different view, that the transient energy deficit can lead to greater oxidation of fat with pre-breakfast exercise compared to later in the day after meals.
    In conclusion, even in energy-balanced condition, 24-h fat
    oxidation is increased if exercise-induced transient energy
    deficit is significant, which is likely to be observed during
    exercise performed before breakfast.

    Didn't get a chance to read the whole thing, but thanks for the link. Always good to have science to debate rather than opinions. Off the top of my head, I can think of two factors that might be involved: 1) I believe this study just looked at a 24 HR period. It's one thing to look at fat oxidation under tightly controlled conditions, another to look at actual fat loss over a period of time. The recent study by Schoenfeld et al (http://www.lookgreatnaked.com/blog/my-new-study-on-fasted-cardio-and-fat-loss-take-home-points/) looked at actual changes in body composition between fasted and non-fasted groups and found no differences. 2) The subjects in the study you reported had an average body fat % between 11%-12%. It has been thought/speculated that the one group who might benefit from fasted cardio are people with low body fat levels, because the fasted state does increase fat mobilization, which becomes an issue at those levels.

    But a good challenge to reconcile the two different results.
  • RoxieDawn
    RoxieDawn Posts: 15,488 Member
    edited April 2016
    Fasted cardio for me too. I am a runner, so if I am running longer than 60 to 70 minutes I start running low (to avoid the wall), I do eat carbs (about 150 - 160 calories) during the run.. But anything less than 60 minutes, I prefer fasted... This is totally a personal preference and your basic needs to train well.
  • Springfield1970
    Springfield1970 Posts: 1,945 Member
    If fasted means 2/3 hours after a good carby meal then, yes I'm fasted.
    I wouldn't dream of doing high heart rate zone stuff if I hadn't eaten for more than that amount of time before.
    Why run a sports car on low octane fuel? Body fat can only burn so fast, ie not fast enough for a proper anaerobic workout.
    Aerobic is different though. As long as you keep it under lactate threshold.
  • yarwell
    yarwell Posts: 10,477 Member
    Azdak wrote: »
    yarwell wrote: »
    Doesn't matter. Keep eating at a deficit it will come off. There is no benefit to fasted vs non fasted. CO is CO be it in the morning, afternoon or evening.

    http://jap.physiology.org/content/jap/118/1/80.full.pdf expresses a different view, that the transient energy deficit can lead to greater oxidation of fat with pre-breakfast exercise compared to later in the day after meals.
    In conclusion, even in energy-balanced condition, 24-h fat
    oxidation is increased if exercise-induced transient energy
    deficit is significant, which is likely to be observed during
    exercise performed before breakfast.

    Didn't get a chance to read the whole thing, but thanks for the link. Always good to have science to debate rather than opinions. Off the top of my head, I can think of two factors that might be involved: 1) I believe this study just looked at a 24 HR period. It's one thing to look at fat oxidation under tightly controlled conditions, another to look at actual fat loss over a period of time. The recent study by Schoenfeld et al (http://www.lookgreatnaked.com/blog/my-new-study-on-fasted-cardio-and-fat-loss-take-home-points/) looked at actual changes in body composition between fasted and non-fasted groups and found no differences. 2) The subjects in the study you reported had an average body fat % between 11%-12%. It has been thought/speculated that the one group who might benefit from fasted cardio are people with low body fat levels, because the fasted state does increase fat mobilization, which becomes an issue at those levels.

    But a good challenge to reconcile the two different results.

    Indeed, the Schoenefeld study was at a calorie deficit with 23 BMI women, so the calorie deficit probably drowns out any effect of exercise timing vs eating especially as they used Bodpod to assess difference in fat.

    When you see 1.6 vs 1.0 kg of weight loss against a +/- 6 kg SEM there's not going to be any statistical significance in a small group either, it would be interesting to see a much bigger group run for longer so that any significance could emerge.