Fasted Cardio Is Bad - AnabolicMinds.com
    • Fasted Cardio Is Bad


      by Brad Longazel Bodybuilding.com

      It's a common practice for athletes, bodybuilders, and other fat loss die-hards to wake up early, skip breakfast, and jump right on the treadmill with an eye toward obliterating body fat. This strategy has been employed by many great fitness athletes, and has received credit for helping them getting rid of those pesky extra pounds.

      The common rationale for the fasted morning workout is that low glycogen levels cause the body to use fat rather than carbohydrates for fuel. Unfortunately, this flies in the face of basic exercise science and physiology. Let me explain.

      The benefits of food consumption—particularly of glucose and protein—far outweigh any perceived benefits from fasting. Having these substances available as fuel will limit protein loss and thus maintain muscle mass, increase performance, and increase fat oxidation post-exercise. For most of us, these are the goals that cause us to work out in the first place.

      The Fuel Continuum

      Normally, the body will use all fuel sources—including carbohydrates, protein, and fat—during exercise. Depending on the intensity and duration of exercise, one will become the primary fuel, but only for a limited time.

      When using carbohydrates as the fuel source for a workout, the body will shift toward greater usage of fat post-workout. Alternatively, if the body burns fat during cardio, it will use carbohydrates afterward. High intensity levels of training, such as HIIT training, produce a greater dependence on carbohydrates as fuel during workout. Then, following this workout, those who follow HIIT will continue to burn fat for far longer than they were in the gym.

      It's important to remember that this fuel delivery system operates on a continuum—it's not simply one fuel source or the other. Many factors determine which fuel source the body will tap at any given time, and it is better to think of fat-burning goals in a time frame of days rather than minutes. In other words, the fat loss from any one early-morning cardio session isn't going to have a significant effect on body composition or overall fat loss.

      The Fat-Burning Myth

      So basic physiology casts doubt on the effectiveness of the fasted workout. What's more, specific research hasn't been much more supportive.

      In one study at the University of Texas at Austin, moderately trained individuals were divided into two groups. One fasted prior to performing low-intensity cardio, and the other consumed carbohydrates. There was no difference between the groups in the amount of fat oxidation during the exercise until the 80-90-minute mark of exercise, at which point there was slight increase in fat oxidation for the fasted group. In the same study, moderate-intensity cardio produced no difference between the fasted and fed groups.

      Two other studies took the same idea and applied it to endurance athletes. Again, no differences were found between fasted and fed groups. The fasted groups in these studies showed evidence of fat being liberated from adipose tissue, but that fat was never fully oxidized. This means that it was re-established into fatty tissue on the body after the exercise bout. So the technique failed the primary goal of early-morning fasted cardio.

      Eat Up And Still Burn

      From an exercise perspective, there are multiple reasons to eat before working out. First and foremost, attempting to engage in high-intensity training on an empty stomach will undermine your performance. Having a pre-training meal primes the body for performance and provides the fuel needed to satisfy the demands of the session. Training intensely on an empty stomach will demand caloric expenditure that the body cannot fully meet, leading to diminished returns.

      Another benefit of eating before exercise is the thermogenic effect from the digestion of the food, which multiple studies have shown actually improves fat oxidation. The process of digestion causes the body's temperature to rise, leading to a greater use of nutrients during exercise. The high level of oxygen consumption during intense exercise intensifies this effect. Indeed, it has been shown that greater use of both fat and carbohydrates occurs after consuming glucose before low- and high-intensity training when compared to not consuming glucose before exercise.

      If your goal is muscle growth or maintenance, fueling up is doubly important. Going into cardiovascular training hungry puts you at risk of significant loss of protein. When each gram you consume is valuable, fasting isn't your fat-loss friend.

      The Numbers Game
      So what's to explain the success many claim with fasted early-morning workouts? Well, the person is working out, and this burns more calories. The same would hold true if you went from training once per day to twice per day, or if you changed from a sedentary lifestyle to regular exercise. As the caloric demand on your body increases, chances are you'll lose weight.

      That's a positive development—but training in a fasted state sets you up to lose the muscle you have worked so hard to create. Eat before you leave for the gym for a better workout experience and better results. And did we say you get to eat breakfast?

      Sources
      • Febbraio MA, Chiu A, Angus DJ, Arkinstall MJ, and Hawley JA. Effects of carbohydrate ingestion before and during exercise on glucose kinetics and performance. J Appl Physiol. 2000; 89: 2220-2226.
      • Gibala MJ, Little JP, van Essen M, Wilkin GP, Burgomaster KA, Safdar A, Raha S, and Tarnopolsky MA. Short-term sprint interval versus traditional endurance training: Similar initial adaptations in human skeletal muscle and exercise performance. J Physiol. 200; 615(pt 3): 901-911.
      • Horowitz JF, Mora-Rodriguez R, Byerley LO, and Coyle EF. Lipolytic suppression following carbohydrate ingestion limits fat oxidation during exercise. Am J Physiol Endocrinol Metab. 1997; 273: E768-E775.
      • Horowitz JF, Mora-Rodriguez R, Byerley LO, and Coyle EF. Substrate metabolism when subjects are fed carbohydrate during exercise. Am J Physiol. 1999; 276(5 Pt 1): E828-E835.
      • Lee YS, Ha MS, and Lee YJ. The effects of various intensities and durations of exercise with and without glucose in milk ingestion on post exercise oxygen consumption. J Sports Med Physical Fitness. 1999; 39: 341-347.
      • Lemon PW and Mullin JP. Effect of initial muscle glycogen levels on protein catabolism during exercise. J Appl Physiol. 1980; 48: 624-629.
      • Schoenfeld B. Does cardio after an overnight fast maximize fat loss? Strength and Conditioning Journal. 2011; 33: 23-25.
      • Schabort EJ, Bosch AN, Weltan SM, and Noakes TD. The effect of a preexercise meal on time to fatigue during prolonged cycling exercise. Med Sci Sports Exerc. 1999; 31: 464-471.
      • Wright DA, Sherman WM, and Dernbach AR. Carbohydrate feedings before, during, or in combination improve cycling endurance performance. J Appl Physiol. 1991; 71: 1082-1088.


      Source: http://www.bodybuilding.com/fun/fuel...y-stomach.html
      Comments 16 Comments
      1. compudog's Avatar
        compudog -
        This article is basically asserting that exercise timing doesn't matter in relation to meal timing, but if that's true then the opposite is also true; meal timing doesn't matter in relation to exercise timing. That presents an awkward conclusion that clashes with the premise of the article though; that whether you do cardio fasted or not does not matter. That's what makes sense, and I think the author fudged this when they wrote: "Training intensely on an empty stomach will demand caloric expenditure that the body cannot fully meet, leading to diminished returns." What does "diminished returns" mean? Does it mean you're going to power out & fall down on the treadmill like a rag doll? Because that's not what happens. I've done cardio that lasted for nearly 20 hours (mountaineering) and I didn't power out. So what does it mean? It doesn't mean anything. It's just a statement made up to support the conclusion.
      1. ITW's Avatar
        ITW -
        Originally Posted by compudog View Post
        This article is basically asserting that exercise timing doesn't matter in relation to meal timing, but if that's true then the opposite is also true; meal timing doesn't matter in relation to exercise timing. That presents an awkward conclusion that clashes with the premise of the article though; that whether you do cardio fasted or not does not matter. That's what makes sense, and I think the author fudged this when they wrote: "Training intensely on an empty stomach will demand caloric expenditure that the body cannot fully meet, leading to diminished returns." What does "diminished returns" mean? Does it mean you're going to power out & fall down on the treadmill like a rag doll? Because that's not what happens. I've done cardio that lasted for nearly 20 hours (mountaineering) and I didn't power out. So what does it mean? It doesn't mean anything. It's just a statement made up to support the conclusion.
        ^ insightful
      1. nicoacademia's Avatar
        nicoacademia -
        True what compudog said.... All i know is if your body is using up fat your efficiency at a higher intensity is lowered...the body will make up ways to cope with what the mind wants. If you are doing higher intensity stuff body will try and use up what freely available glycogen. If not in will convert and burn fat/muscle.
      1. jamesm11's Avatar
        jamesm11 -
        A-->B does not mean B-->A but I understand how you came to that your conclusion.



        The assertion in this article has been proved in other studies as well. Also they have dispelled you need to eat within 30 minutes post workout, the anabolic window is quite a bit longer.
      1. aLinux's Avatar
        aLinux -
        Besides fat loss....If I aint primed with fuel before anything in a gym, I cramp up like a bitch. Food is king. One thing I always wondered is how long to wait to hit cardio or the weights after eating... I wait at least an hour or more..maybe I should go sooner to get the thermo or barf effects : )
      1. compudog's Avatar
        compudog -
        Originally Posted by jamesm11 View Post
        A-->B does not mean B-->A but I understand how you came to that your conclusion.



        The assertion in this article has been proved in other studies as well. Also they have dispelled you need to eat within 30 minutes post workout, the anabolic window is quite a bit longer.
        Simple, if your body is going to "choose" fuels regardless of when you ate last, then it doesn't matter when you ate last in relation to when you do your cardio. In other words, whether you do cardio fasted or not doesn't make any difference. Regarding meal timing in general, I agree with you, 30 minutes is a ridiculously short window. Personally I think if a person eats twice or even once a day it's about the same effect as eating 6 or 12 times a day for that matter, but that's just my opinion. YMMV.
      1. Lutztenways's Avatar
        Lutztenways -
        completely agree with compudog
      1. saggy321's Avatar
        saggy321 -
        Originally Posted by Lutztenways View Post
        completely agree with compudog
        Up to a point. But the article on mentions fat oxidation in relation to low intensity and moderate intensity cardio. Can the same be said for HIIT or weight training, ie timing and profile of nutrition has no bearing upon type of fuel oxidised during exercise. Speaking for myself I notice no difference when doing moderate cardio on an empty stomach but notice a difference when I'm training with weights.
      1. mr.cooper69's Avatar
        mr.cooper69 -
        What a terrible article.
      1. soontobbeast's Avatar
        soontobbeast -
        see below
      1. soontobbeast's Avatar
        soontobbeast -
        If we're going to talk about what has the best net outcome, where is the mention of autophagy?

        By far, the greatest benefit of fasted cardio is the enhancement of the autophagic process. Forget about the issue of burning fat or glycogen, what about life extension and disease prevention? Autophagy is an integral part of keeping us healthy. It is our body's way of cleaning house.

        When nutrients aren't readily available as with fasting, the autophagic process is most active. What's more, when you don't have nutrients AND you are exercising, autophagy is accelerated.

        If we're going to talk about what ''goals that cause us to work out in the first place'', I would say it is to be healthier. Fasting is one of the most effective life extending tools we have.

        Oh, and by the way, empirical evidence supports the fact that protein metabolism is negligible in instances of fasted training. Ask anyone who does intermittent fasting. Personally, I have GAINED muscle AND strength while fasting 20 hours a day, several days of the week, without the use of hormone enhancing 'supplements'.

        When will the myth of 6 meals a day and pre-workout meals just die already?
      1. asdfvtn's Avatar
        asdfvtn -
        There's a few solid points in the author's understanding of exercise physiology, but as compudog points out, he's getting confused at some things. I'm only hitting a couple of the bigger things, but,
        The "fuel continuum" he's talking about is true only to a certain extent. Unless you're doing fairly low intensity workouts all the time or your body is condition to use the fat oxidation cycle more (high endurance athletes) carbohydrates are almost always relied on primarily. Whenever you work out, your RER values shoot up. The RER values range from 0.7 (fat use) to 1.0 (carbohydrate use). It can be greater than 1.0, but that's due to buffering on your H+ ions.
        Additionally, HIIT isn't effective because of it's "greater dependence on carbohydrates", it's effective because it allows you to work at a higher intensity for a longer period of time by having rest intervals. It burns more energy after the workout has ended due to more muscle fiber repairs it has to do as well as the accumulated oxygen deficit it's built up.
        Another point includes the thermogenic effect of food. Yes, food does have a thermogenic effect. The problem is, your body doesn't digest much food while you're working out. The majority of your blood from your digestive organs are diverted to your skeletal muscles to provide more oxygen.

        Breakfast, as more and more people are starting to know, isn't as important as it once was thought. I do love eggs though.
        One important thing people need to remember out of this article though, is that you do start to breakdown muscle as a fuel when your body isn't fed and isn't able to keep up with the energy demands. (Berkhan suggests having some BCAA's before this to get around this problem).
      1. ballerj63's Avatar
        ballerj63 -
        4-6 meals all day, everyday baby! I tried that IF BS and felts weak as crap on my lifts. There ain't no shortcuts to a good physique period. It takes time, dedication, a smart routine, and most importantly nutrition.

        Those that are IF'ing saying that this is how we used to eat is just a bunch of crap. Have you ever seen the early man diced to the socks like competitive natural bodybuilders? I think not!!!! They look more like cachetic Marathon runners.
      1. DelaRone's Avatar
        DelaRone -
        People, don't believe everything you read...this is garbage, how can you say there's a point of diminished returns? Fat is stored energy, no energy from foods means.....it's fat burning time!
      1. Facetoface's Avatar
        Facetoface -
        As anecdotal evidence against this article; When I started training in the morning instead of the afternoon, I took advantage of the fact that I could now train fasted (I wake up and all I have is a preworkout and bcaas) and within a month or two I had a 6 pack out of the blue, my wife said something when I was getting ready one day.. I looked down and was like "whoa, wtf".. needless to say I've trained fasted ever since, and made pretty good strength and size gains too.. (I drink down lots of protein and high glycemic carbs right after working out)..
      1. alexoc949's Avatar
        alexoc949 -
        Originally Posted by ballerj63 View Post
        4-6 meals all day, everyday baby! I tried that IF BS and felts weak as crap on my lifts. There ain't no shortcuts to a good physique period. It takes time, dedication, a smart routine, and most importantly nutrition.

        Those that are IF'ing saying that this is how we used to eat is just a bunch of crap. Have you ever seen the early man diced to the socks like competitive natural bodybuilders? I think not!!!! They look more like cachetic Marathon runners.
        you likely weren't doing it right.