Marks Daily Apple
Serving up health and fitness insights (daily, of course) with a side of irreverence.
17 Nov

Dear Mark: Post-Workout Fasting

Empty BowlBefore I jump into this week’s Dear Mark post I wanted to direct everyone’s attention to Andrew Rubalcava’s site, Go Healthy Go Fit. Andrew just published an interview with me. Here are just a few of the questions I answered:

Who have been your top 3 favorite bloggers over the years?

How did you get involved in physical competition such as your experience as a triathlete?

If you could give a few words of advice for those who are just beginning to enter a world of health and fitness, what would you say?

Check out the interview here, and check back on Thursday when I’ll be publishing Andrew’s guest post on how to stay healthy no matter what type of lifestyle you lead.


For this week’s Dear Mark I thought I’d follow up on the issue of post-workout nutrition from a couple of weeks ago. I mentioned in Dear Mark: Muscle Building and Carbs that I fast once in awhile after a workout. I’ve gotten a lot of comments and messages about this point since that post. So, here’s my take on PWO fasting as promised!

As I mentioned in the earlier Dear Mark, after a workout is prime opportunity for protein synthesis. For that reason I usually do a high protein snack in the first 30-60 minutes to capitalize on that benefit. (Carbs, as you recall, aren’t necessary for the enhanced synthesis, and I don’t recommend them in any form after a workout that’s under an hour’s time.) However, I also occasionally choose to fast after a workout to maximize another physiological benefit – the rise in human growth hormone (HGH), which critically influences everything from bone density to muscle mass and organ reserve to general cell reproduction in the body’s systems.

As I’ve mentioned before in relation to intermittent fasting (IF), fasting is known to significantly increase HGH secretion. (Grok’s survival depended on the ability to hormonally kick start efficiency and preservation modes during the lean days.) Research has also consistently confirmed that intense exercise, particularly resistance training, also triggers a rise in HGH. While I can (and do) take advantage of each individual method, combining the two opportunities can maximize my body’s HGH release.

Furthermore, insulin suppresses HGH. Skipping the carb snack and subsequent insulin upsurge goes a long way post-workout. But skipping anything that might even mildly raise insulin levels (that heightened sensitivity in the muscles, you know!) can be better yet.

And I should add that I do this without worrying about a blow to muscle mass. Fasting occasionally post-workout, provided I maintain a high protein diet the rest of the time, doesn’t negatively impact nitrogen retention and protein synthesis. Just as I mentioned last week that the body won’t suffer if you don’t force reloading of glycogen stores with a shot of glucose after a workout, I’ll go out on a limb and say that you’re unlikely to waste away if you don’t fuel muscles immediately with protein as well. The fact is HGH has its own protein conservation potential. And, while the post-workout period is an optimum opportunity for protein synthesis, it’s not the sole time your body is able to use protein and provide for the muscles’ needs.

While I’m not suggesting fasting after every workout, I think it’s worth doing occasionally. (After all, Grok probably wasn’t successful with every hunt.) In the spirit of IF and recreating patterns of our primal ancestors’ lives, varying your eating/exercising/fasting practices ultimately allows for maximizing the hormonal and upregulating benefits of different physiological scenarios.

Finally, yet another means of naturally encouraging HGH release is getting a good night’s sleep. After a good fast (and a great workout), I find this part comes the easiest. Honestly, it’s the best sleep I get.

As always, thanks for your questions and comments. Keep ‘em coming!

DeathByBokeh Flickr Photo (CC)

Further Reading:

The Hype Over Human Growth Hormone

1 Meal vs. 3 Meals

How To: Intermittent Fasting

You want comments? We got comments:

Imagine you’re George Clooney. Take a moment to admire your grooming and wit. Okay, now imagine someone walks up to you and asks, “What’s your name?” You say, “I’m George Clooney.” Or maybe you say, “I’m the Clooninator!” You don’t say “I’m George of George Clooney Sells Movies Blog” and you certainly don’t say, “I’m Clooney Weight Loss Plan”. So while spam is technically meat, it ain’t anywhere near Primal. Please nickname yourself something your friends would call you.

  1. The occasional IF does wonders for fat loss.

    Jeff wrote on November 10th, 2010
  2. One thing I wonder about regarding post work out carbs…doesn’t elevated insulin suppress cortisol? How does one factor that in as a mitigator to the catabolic effects of the elevated cortisol? As of now, I still have a banana as part. I have wondered about whether to ditch it or not.

    Phil wrote on February 17th, 2011
  3. Hey Mark,

    I read different approaches to preworkout nutrition while fasting. Some say your first meal after fasting should be the preworkout meal while others say the first meal should be post workout meal. What do you think ?

    One more thing, right now I follow the traditional 6 small meals per day and do my cardio on empty stomach in the morning. How would you place the cardio if I do IF and if my eating period is between 17.00 – 24.00 *


    Haluk wrote on July 26th, 2011
  4. Post-workout nutrition is grossly over-hyped pseudoscience. Scientifically, there is no magic nutrition window for muscle growth, which actually continues 3+ days after each workout. Plus, the body has more than enough protein available to recycle for muscle needs for an hour or two (actually, much longer than that).

    The notion of a “magic window” for post-workout nutrition is just based on misunderstanding a small portion of research taken grossly out of context.

    Steve wrote on January 1st, 2012
  5. Hello Mark,

    I was wondering, if I were to fast PWO when I did eventually eat does it really matter too much what level of protein I eat? Should I strive for a fast digesting protein as I would PWO or just go with a high quality protein regardless of the pace of digestion? And also after that fasting period are you still a fan of hardly any carbs or none at all?

    Brandon Adams wrote on February 23rd, 2012
  6. Hey, when you fast post-workout, are you being in the ‘fed’ state the first half of the day? Or do we fast, workout and continue fasting?

    Edwin wrote on September 7th, 2012
  7. Hi,

    Sometimes if I skip a meal I get a bit light headed – last night I did an hours resistance intense workout class and came home at 9 and wanted something to eat – I get a bit grouchy if I don’t eat! So I just had some steamed veggies and some yoghurt after, and I woke up the next morning feeling really hungry. My question is, would this have had any benefits like IF if I did eat something last night?

    sarah wrote on March 12th, 2013
  8. Hi,

    Sometimes if I skip a meal I get a bit light headed – last night I did an hours resistance intense workout class and came home at 9 and wanted something to eat – I get a bit grouchy if I don’t eat! So I just had some steamed veggies and some yoghurt after, and I woke up the next morning feeling really hungry. My question is, would this have had any benefits like IF if I did eat something last night?

    Read more:

    sarah wrote on March 12th, 2013
  9. Whether it is ok to fast PWO or not depends on many factors.

    1) How long are you working out ?

    2) How many calories are you consuming daily ?

    3) What is your Body Fat % ?


    If your goal is to build muscle, then you want to be eating on a surplus and not on a deficit, so you will have to get proper nutrition, proper macros and supplements if necessary to assure muscle health and growth.

    If your goal is to slim down, tone muscle/maintain muscle, then you have adding some heavy lifts to your workout, no more than about 20-30 minutes, low rep but heavy. Combined with proper protein and fat, for those who are on keto type diets. You can’t have your cake and eat it. If you want to lose weight, you can’t also want to body build muscles 😀

    If you are a newbie you might get away with it,by what’s called newbie gains.

    One thing to keep in mind never go on a too high calorie deficit (VLC Very low calorie diet) combined with long workouts, cardio, etc….. Muscle loss is the least of your concern but other bigger problems like screwing your metabolism and immune system. If your body fat % is on the low side and have stubborn fat to lose (few pounds) then I don’t recommend working out and fasting. Remember that if you work out and expand more calories than you ingest, combined with a VLC and low body fat %, you are going to have your body hold on to your fat and your weight loss will STALL you might even gain weight, and you will lose muscle mass… If you want to maintain muscle / tone,whilst keeping slim you can use the CKD (Cyclic Keto) whereas you go intermittent low carb days followed by carb days, etc…..cycling your glycogen stores preventing overspill and gaining fat. But you won’t build muscles on any diet,
    on ANY deficit. Fasting PWO on occasion won’t hurt you,
    providing the rest of the day you eat well, you eat enough calories, and get proper supply of proteins based on your LBM, you should preserve lean mass. Otherwise you are asking for inevitable lean muscle loss.

    For optimal recovery and growth it is advised to have a PWO meal, ideally both carbs and protein, but if you don’t want the carbs, at least the protein ! If by fasting you mean working out evening and fasting over night until breakfast (which is probably around 12-14 hour fast) that’s not too good, hinders recovery and in the long run muscle loss.

    Rimmer66 wrote on March 10th, 2014
  10. Mark sorry bad writing, do not speak English, I have a doubt, weight only 57 pounds and I’m 1.82 meters tall, my body fat percentage is very low even then I do not eat carbs after training?

    Felipe wrote on July 30th, 2014
  11. Jurors who’re also filmmakers could submit work, however solely during months during which they aren’t seerving as a
    juror for the competition.

    online video contest websites wrote on February 12th, 2016

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