7

votes

Fasting after Strength Training

Answered on August 19, 2014
Created April 13, 2010 at 11:31 AM

Hi guys:

Does anybody know of any ill effects of fasting after strength training? I'm doing a 24 hr fast after a P90X strength training workout; will the fast slow down muscle repair?

Thanks, Chris D.

Ca2c940a1947e6200883908592956680

(8574)

on April 13, 2012
at 02:26 PM

Jenna: leangains.com probably has the most links to papers in regards to this. Exercise does lower insulin and raise human growth hormone (hGH), and not eating insulin raising foods directly after your workout puts you in a better position to utilise HGH and not suppress the uptake by insulin. You are also in a position then to burn fat for longer too.

Ca2c940a1947e6200883908592956680

(8574)

on April 13, 2012
at 02:26 PM

Jeanna: http://leangains.com probably has the most links to papers in regards to this. Exercise does lower insulin and raise human growth hormone (hGH), and not eating insulin raising foods directly after your workout puts you in a better position to utilise HGH and not suppress the uptake by insulin. You are also in a position then to burn fat for longer too.

9f2b5def0bc7fd8ad615637d1ffeb9ec

on December 10, 2010
at 03:58 AM

There is some debate on this, but Charles Poliquin, who has coached Olympic champions in multuple sports, claims that insulin sensitivity is higher post workout. See #8 in this list: http://www.charlespoliquin.com/ArticlesMultimedia/Articles/Article.aspx?ID=33

50637dfd7dc7a7e811d82283f4f5fd10

(5838)

on December 09, 2010
at 09:44 PM

"I play for keeps!" - Ricky Bobby

1a8020e101199de55c1b3b726f342321

(1973)

on December 07, 2010
at 10:09 PM

Most likely, Volek's got a create presentation on the subject. http://www.mediafire.com/?psc5jkeax5bmlhv

1a8020e101199de55c1b3b726f342321

(1973)

on December 07, 2010
at 10:09 PM

Most likely, Volek's got a create presentation on the subject.

1a8020e101199de55c1b3b726f342321

(1973)

on December 07, 2010
at 10:05 PM

LiveForIt: Depleted glycogen needs to be replaced, whether from diet or through GNG which will pull from amino acids. See http://jap.physiology.org/cgi/reprint/96/2/674.pdf

1a8020e101199de55c1b3b726f342321

(1973)

on December 07, 2010
at 09:50 PM

The lower testosterone levels after post workout meal/shake may be due to an increased clearance of testosterone according to this paper, seems unclear if it's a negative thing. http://jap.physiology.org/cgi/content/abstract/76/2/839

Af842c68e3d07fa0e35b4274f3acaeec

on August 01, 2010
at 01:45 AM

I think you're thinking of Mark Sisson, he recommends fasting post workout. There definitely is an increased HGH release by fasting post workout, but I think fasting anymore than 3-4 hours aren't going to get you any more benefit. Robb doesn't recommend it, but he has no problem with it; try it out, see how you look/feel/perform, I think that's his approach.

5de2fffda92c0bf2be7ede10cad55546

(1781)

on April 27, 2010
at 12:41 PM

My understanding from reading Body by Science by Doug McGuff, 24 hours after exercise inflammation sets in, enzymes break down and metabolize the damaged tissue. For several days additional cells aid in the accumulation of lysosomes. This inflamation response brings further damage to the muscles and can continue for several days. After these inflammation responses have been completed signs of tissue remodeling are observed. The fibres build back to their preworkout size and if further time is allowed, will build up to a level greater than before. This can take from 5 days to 6 weeks.

03aeff8d87a3b53a449b5b8e9158da98

(3268)

on April 19, 2010
at 04:19 PM

diswonkdiswill27, I think you are slightly misrepresenting the study that Brad talks about. He doesn't say "protein has hardly any effect." The study seemed to indicate that .7 grams of protein per pound of bodyweight is suffience to elecict a fairly significant hypertrophic response. So, bodybuilders might not need as much protein as they tend to consume. But that's hardly the same as saying that nutrition has NO role in muscular development!

254093d123868fbc81862e037e96b317

on April 16, 2010
at 12:09 AM

i've read that protein has hardly any effect on muscle growth. look at brad pilon's how much protein link: http://bradpilon.com/healthy-ramblings/how-much-protein-do-you-need-to-build-muscle/ its actually muscle activity that causes your muscle to grow, not nutrition. if you think of it like an arm in a cast, that arm will degrade bc of no activity but its getting the same nutrients as your non casted arm. i think the benefit of fasting post workout would be to just utilize more fatty acids for energy for a longer period of time but make sure not to chronically restrict calories - just acutely

03aeff8d87a3b53a449b5b8e9158da98

(3268)

on April 14, 2010
at 09:27 AM

Pieter, biochemistry is a learning process for a lot of us... especially me! But from what I understand, yes, the process does take a while, so the availability of protein within the first hour post-workout is not going to be totally decisive. (I think glycogen replenishment, if that is what you are looking for, occurs much faster). But the OP was talking about a post-workout fast of 24 hours! That would definitely impair recovery/growth, I believe.

691f120a3e7a1a036845d105d86c99a3

(3641)

on April 13, 2010
at 10:05 PM

i am gonna look through my PT books but I think I just meant recovery and fixed it in an edit. without glycogen your muscles experience fatigue and thus another strenuous workout might be difficult to take on. i will see if glycogen depletion results in hindered muscle repair, although id think it would in some way as i am pretty sure some insulin reaction is needed to protein to be put to use in repairing muscle... (i am not a doctor or even a personal trainer, just an enthusiast.)

03aeff8d87a3b53a449b5b8e9158da98

(3268)

on April 13, 2010
at 08:29 PM

Frankly, I'm surprised by this. I have a lot of respect for Rob, so I am going to have to look into this some more.

1340fe0b7e7b01683ea33042092e05d6

(1693)

on April 13, 2010
at 08:24 PM

Im curious, as I do not know the answer, but how does glycogen aid in repair of muscle tissue?

89e238284ccb95b439edcff9e123671e

(10299)

on April 13, 2010
at 06:52 PM

Sorry Glenn, can't help you further. Maybe check Art De Vany's site, or ask someone who is subscribed to his paying blog. One question I have myself: are muscles really deprived of amino acids if you don't eat? And related: when does the muscle repair/growth occur mostly? In the first few hours after the workout, the day after, or the second day? Sorry, just question, don't know myself...

65125edd5aafad39b3d5b3a8b4a36bb7

(6082)

on April 13, 2010
at 05:51 PM

That makes sense from a reenactment point of view, but some scientific evidence would be nice.

03aeff8d87a3b53a449b5b8e9158da98

(3268)

on April 13, 2010
at 05:11 PM

So... deprive your muscles of the amino acids they need for repair, in order to reduce the (small) insulin spike from protein ingestion, in order to minimize the (small) impact insulin has on growth hormone, because HGH is necessary for (long-term) muscle hypertrophy? I'm confused!

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13 Answers

6
03aeff8d87a3b53a449b5b8e9158da98

(3268)

on April 13, 2010
at 05:05 PM

I always find that trying to answer questions like based on re-enactment theories is just too speculative.
From the point of view of biochemistry, it's quite difficult for the muscles to repair and rebuild themselves if they are deprived of nutrients after your workout. If you've burned up a good part of your glycogen stores and you don't replenish available amino acids, what are the muscles supposed to use for repair? I don't practice pre-workout fasting myself, but I can sort of see the logic. But fasting afterward doesn't really make sense to me.

4
894d4fe323e26e19abb8119899da07bd

on December 07, 2010
at 08:01 PM

I was researching this exact same things a few days ago and came across a "IF 101" post that breaks down the various methoodologies from the Warrior Diet and Leangains (Daily Fasting) and the 1-3x a week fasts that Eat Stop Eats recommends. It does a great job of explaining the benefits and downsides to each option and gives you enough information to determine which is the best route to go.

http://www.fitnessspotlight.com/2008/02/27/intermittent-fasting-101-how-to-start-part-i/

I got to this from a great blog - http://eatsleepfast.blogspot.com/

Hopefully this helps, I can't begin to espouse the benefits as I am just starting to toy with with this.

4
0d2dec01a5ed9363a9915e111ae13f7e

on April 13, 2010
at 01:00 PM

Aaah, but then, our paleo ancestors may have worked their butts off and missed the beast, going all out to get food and failing! Then a fast was forced upon them!

I like the randomness of paleo, so I mix up fasting pre- and post- workouts.

3
1340fe0b7e7b01683ea33042092e05d6

on April 13, 2010
at 07:59 PM

Rob Wolff talks a bit about this subject in his last few pod casts. If I quote him wrong, someone correct me.

-He is a fan of fasting, no more than 14-15 hours though during sessions. -He also mentions fasting after strength training maximizes HGH, testosterone levels. And I remember him saying that the body has plenty of "unused proteins" that can be easily recycled through various pathways to help regenerate muscle tissue after workouts.

I do forget though how long he advocated to fast after workouts, I want to say 1 or 2 hours? I could be getting him and Mark Sisson's view points confused to be honest. Will have to take some more time to organize those..

03aeff8d87a3b53a449b5b8e9158da98

(3268)

on April 13, 2010
at 08:29 PM

Frankly, I'm surprised by this. I have a lot of respect for Rob, so I am going to have to look into this some more.

Af842c68e3d07fa0e35b4274f3acaeec

on August 01, 2010
at 01:45 AM

I think you're thinking of Mark Sisson, he recommends fasting post workout. There definitely is an increased HGH release by fasting post workout, but I think fasting anymore than 3-4 hours aren't going to get you any more benefit. Robb doesn't recommend it, but he has no problem with it; try it out, see how you look/feel/perform, I think that's his approach.

1a8020e101199de55c1b3b726f342321

(1973)

on December 07, 2010
at 09:50 PM

The lower testosterone levels after post workout meal/shake may be due to an increased clearance of testosterone according to this paper, seems unclear if it's a negative thing. http://jap.physiology.org/cgi/content/abstract/76/2/839

2
0fb8b3d6dcfb279b0f7e050d2d22510f

(4645)

on April 13, 2010
at 08:15 PM

Yes, Art talks about this- but I take much of what he says lately with a grain of salt. He talks about waiting a FEW hours before protein to allow this hormone to kick in...but I thought I got better results with raw milk and whey after a SERIOUS workout. Its the only time I drink any milk is after this type of workout, its what milk does best.

2
89e238284ccb95b439edcff9e123671e

(10299)

on April 13, 2010
at 01:20 PM

I think Arthur De Vany talks about this. And if I'm correct, one of the main reasons to fast after the workout has to do with insulin (protein also causing an insulin spike), and insulin causing growth hormone levels to drop.

EDIT Just an addition: Mark Sisson has a post on post-workout fasting here http://www.marksdailyapple.com/post-workout-fasting/

hope this helps

254093d123868fbc81862e037e96b317

on April 16, 2010
at 12:09 AM

i've read that protein has hardly any effect on muscle growth. look at brad pilon's how much protein link: http://bradpilon.com/healthy-ramblings/how-much-protein-do-you-need-to-build-muscle/ its actually muscle activity that causes your muscle to grow, not nutrition. if you think of it like an arm in a cast, that arm will degrade bc of no activity but its getting the same nutrients as your non casted arm. i think the benefit of fasting post workout would be to just utilize more fatty acids for energy for a longer period of time but make sure not to chronically restrict calories - just acutely

03aeff8d87a3b53a449b5b8e9158da98

(3268)

on April 14, 2010
at 09:27 AM

Pieter, biochemistry is a learning process for a lot of us... especially me! But from what I understand, yes, the process does take a while, so the availability of protein within the first hour post-workout is not going to be totally decisive. (I think glycogen replenishment, if that is what you are looking for, occurs much faster). But the OP was talking about a post-workout fast of 24 hours! That would definitely impair recovery/growth, I believe.

03aeff8d87a3b53a449b5b8e9158da98

(3268)

on April 19, 2010
at 04:19 PM

diswonkdiswill27, I think you are slightly misrepresenting the study that Brad talks about. He doesn't say "protein has hardly any effect." The study seemed to indicate that .7 grams of protein per pound of bodyweight is suffience to elecict a fairly significant hypertrophic response. So, bodybuilders might not need as much protein as they tend to consume. But that's hardly the same as saying that nutrition has NO role in muscular development!

5de2fffda92c0bf2be7ede10cad55546

(1781)

on April 27, 2010
at 12:41 PM

My understanding from reading Body by Science by Doug McGuff, 24 hours after exercise inflammation sets in, enzymes break down and metabolize the damaged tissue. For several days additional cells aid in the accumulation of lysosomes. This inflamation response brings further damage to the muscles and can continue for several days. After these inflammation responses have been completed signs of tissue remodeling are observed. The fibres build back to their preworkout size and if further time is allowed, will build up to a level greater than before. This can take from 5 days to 6 weeks.

03aeff8d87a3b53a449b5b8e9158da98

(3268)

on April 13, 2010
at 05:11 PM

So... deprive your muscles of the amino acids they need for repair, in order to reduce the (small) insulin spike from protein ingestion, in order to minimize the (small) impact insulin has on growth hormone, because HGH is necessary for (long-term) muscle hypertrophy? I'm confused!

89e238284ccb95b439edcff9e123671e

(10299)

on April 13, 2010
at 06:52 PM

Sorry Glenn, can't help you further. Maybe check Art De Vany's site, or ask someone who is subscribed to his paying blog. One question I have myself: are muscles really deprived of amino acids if you don't eat? And related: when does the muscle repair/growth occur mostly? In the first few hours after the workout, the day after, or the second day? Sorry, just question, don't know myself...

2
D5369279b7a9603265376dc70e6fb50c

(30)

on April 13, 2010
at 12:01 PM

from a paleo perspective it seems awkward. If our paleo ancestors just completed some major work either in the hunt or some sort of heavy lifting for construction it seems they would have either eaten their kill or had some sort of food after their trial.

65125edd5aafad39b3d5b3a8b4a36bb7

(6082)

on April 13, 2010
at 05:51 PM

That makes sense from a reenactment point of view, but some scientific evidence would be nice.

0
6cf3281bc8e574207c61429d5ae795ab

on April 13, 2012
at 02:14 PM

While I am uncertain as to benefits of fasting either prior to or subsequent to workouts - I think the scientific evidence is not yet substantial enough to make a firm call on this - I find the idea that paleolithic man fasted on hunts has no scientific credibility -still less that this should be accepted as having any sort of long-term benefits to modern exercisers.

Ca2c940a1947e6200883908592956680

(8574)

on April 13, 2012
at 02:26 PM

Jeanna: http://leangains.com probably has the most links to papers in regards to this. Exercise does lower insulin and raise human growth hormone (hGH), and not eating insulin raising foods directly after your workout puts you in a better position to utilise HGH and not suppress the uptake by insulin. You are also in a position then to burn fat for longer too.

Ca2c940a1947e6200883908592956680

(8574)

on April 13, 2012
at 02:26 PM

Jenna: leangains.com probably has the most links to papers in regards to this. Exercise does lower insulin and raise human growth hormone (hGH), and not eating insulin raising foods directly after your workout puts you in a better position to utilise HGH and not suppress the uptake by insulin. You are also in a position then to burn fat for longer too.

0
77877f762c40637911396daa19b53094

(78467)

on December 09, 2010
at 09:02 PM

my understanding from what i've read is following: strenuous exercise uses muscle glycogen stores as a substrate to raise blood glucose levels and thus leads to a temporary physiological insulin resistance (body kind of feeds on itself), so therefore consuming anything right after work out is counterproductive or even deleterious (bg is already high so anything else that makes it even higher screws things up); besides, i don't about others' experience but if i had a really challenging work out, eating immediately afterward is the last thing i would think of - at least for an hour or two food seems even repulsive - and if you don't feel that way perhaps you should have tried harder, though

9f2b5def0bc7fd8ad615637d1ffeb9ec

on December 10, 2010
at 03:58 AM

There is some debate on this, but Charles Poliquin, who has coached Olympic champions in multuple sports, claims that insulin sensitivity is higher post workout. See #8 in this list: http://www.charlespoliquin.com/ArticlesMultimedia/Articles/Article.aspx?ID=33

0
9f2b5def0bc7fd8ad615637d1ffeb9ec

on December 09, 2010
at 02:04 AM

I experimented with fasting pre and post workout. I burned off fat like nobody's business, but I also lost more muscle than I would like. Now I usually fast pre, but always take whey post-workout and I feel and look much better.

Although realistically a hunter would sometimes miss a meal after a hard but fruitless hunt, I think it better to train as if you always get the prize.

50637dfd7dc7a7e811d82283f4f5fd10

(5838)

on December 09, 2010
at 09:44 PM

"I play for keeps!" - Ricky Bobby

0
5e36f73c3f95eb4ea13a009f4936449f

(8280)

on December 09, 2010
at 12:50 AM

My question is, what exactly is your goal? You're doing strength exercises (build muscle) but are fasting after (lose weight?). If it is to build muscle, I think you'd be sabotaging your efforts.

The general rule for bodybuilders is to get protein/carbs before and after workout to provide an abundant amount of resources to lift heavy and repair the damaged muscles as fast/optimally as possible.

Will you grow fasting after hard exercise? It's possible, although the general concern is after strenuous exercise, you're in a catabolic state and your body would break down your muscles to provide the amino acids to repair (counterproductive wouldn't you think?).

However, the general rule doesn't apply to everyone. People are different, and what I've seen from Robb Wolf and others is basically, get everything working right first with the standard methods that everyone understands. THEN start playing around with fasting and the like to see if you're body reacts positively to it. You need to stick with one method and understand how it works for you before you can compare other methods.

0
16846467115e18d283565a19c374ee07

(323)

on December 07, 2010
at 08:25 PM

Try it and see how you feel. I, when the schedule doesn't allow or I just plain ol' forget, don't eat after a work out. Go to crossfit, shower, get to work, BAM, all of a sudden I remember I didn't eat anything. I'll usually try to work in some protein at that point, but I never feel fatigue or ill in the few hours after a WOD. Would I say there is a definite improvement or a definite drawback to not eating after a workout? Not in my personal experience, no.

Like I said, if you're curious about it, try it. That's what I like about Paleo and Crossfit, you get to test out what works best for YOU

0
691f120a3e7a1a036845d105d86c99a3

(3641)

on April 13, 2010
at 07:59 PM

I believe muscle recovery would be affected and would lead to poor performance on your next PX90 work out. You could help your recovery by having a bit of readily available protein like a whey shake right after (~30 min) your PX90 workout to help get some fuel in your body that could be converted to glycogen and aid in recovery... then i guess go on your fast from there. I probably would avoid another stressful workout till i was eating again or accept that I wont be doing max effort.

691f120a3e7a1a036845d105d86c99a3

(3641)

on April 13, 2010
at 10:05 PM

i am gonna look through my PT books but I think I just meant recovery and fixed it in an edit. without glycogen your muscles experience fatigue and thus another strenuous workout might be difficult to take on. i will see if glycogen depletion results in hindered muscle repair, although id think it would in some way as i am pretty sure some insulin reaction is needed to protein to be put to use in repairing muscle... (i am not a doctor or even a personal trainer, just an enthusiast.)

1340fe0b7e7b01683ea33042092e05d6

(1693)

on April 13, 2010
at 08:24 PM

Im curious, as I do not know the answer, but how does glycogen aid in repair of muscle tissue?

1a8020e101199de55c1b3b726f342321

(1973)

on December 07, 2010
at 10:05 PM

LiveForIt: Depleted glycogen needs to be replaced, whether from diet or through GNG which will pull from amino acids. See http://jap.physiology.org/cgi/reprint/96/2/674.pdf

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