Post-Workout Carbs – Crucial or Counter-Productive?

by Mark McManus on June 23, 2008

I’m ditching post-workout carbs.

Taking in carbohydrates in the post-workout period has long been seen as an essential component of your muscle building regimen. The more I research though, the more likely it seems that post-workout carbohydrates will have no impact or may even be counter-productive.

Please note that this advice does not apply to a higher carb diet like the 40/30/30 GLAD approach. For that diet, work out the amount of post-workout carbs needed and stick to it.

First we’ll look at the reasons why I’ve made this decision and then the logical implications following it.

Reasons For Ditching Post-Workout Carbs

(1) Study shows inclusion of carbohydrate in post-workout shake does not increase protein synthesis.

The following study took place in the Netherlands, the subjects being healthy young men. What was great about this study was that it was truly scientific in that it split the men into 3 groups, each ingesting different combinations of protein & carbohydrates. Therefore the only variable was the level of carbohydrate.
Each group performed resistance training for 60 minutes and was given either protein or a combination of protein and carbohydrate each hour for 6 hours after training. The amount of protein for all the groups was 0.3g per kg of bodyweight. The protein and carbs varied as follows:

Group 1 – Just Protein, no carbs
Group 2 – Protein with 0.15 g per kg of body weight of carbohydrate
Group 3 – Protein with 0.6 g per kg of body weight of carbohydrate

Protein synthesis rates were then measured for 6 hours after training. The results?

The intake of protein after training increases protein synthesis
The addition of carbohydrate (whether in small or large amounts) to this protein did not further increase protein synthesis at all. That may be surprising but in my opinion it’s great news, especially for carb-cycling MuscleHackers

study: Am J Physiol Endocrinol Metab. 2007 Sep;293:E833-E842

(2) The Impact of Carbs on Growth Hormone

Growth Hormone levels are elevated after resistance training. It’s well known that as insulin levels increase in the body, growth hormone decreases. A large spike in insulin will occur with the ingestion of high GI post workout carbs. Therefore, it would seem that carb intake after resistance training may be counter-productive.

(I’m still searching for a study in respect to the above point. The only study I could find suggested that carbs AND protein post workout did not blunt growth hormone release. What is needed is an approach similar to the study above which isolates the variables e.g. would protein ingestion alone have a more favorable impact on growth hormone levels?) Therefore, at the moment, this is intuitive.

(3) Impact of Post-Workout Carbs on Fat-Oxidation

Obviously if you are taking time to refill your muscle glycogen stores with carbohydrate after a workout, you are reducing the amount of fatty acids your body will use to provide the energy it needs.

In order to keep fat-oxidation (using fat for energy, whether from body-fat or food) at maximum levels, it would make sense to leave the carbs out of your post-workout shake. In doing so you encourage the body to tap into it’s stored fat.

So, what are the implications of this information?

(1) It makes the MANS diet easier to follow. Let’s say that your daily carb intake Monday – Friday is 40 grams. You now won’t lose 5 – 15 grams in a post-workout shake. You can spread those extra carbs throughout the day or have in one meal e.g. you may feel you benefit from more carbs in you pre-workout meal.

(2) Increased fat-burning. For the whole of the low-carb period, you now encourage the use of fatty acids for energy.

(3) Possibly increased growth hormone levels throughout the low-carb period of the MANS bodybuilding diet.

The exclusion of post-workout carbs seems to be a very positive move indeed. If you are worried about depleted glycogen levels, remember that you re-fill these ‘storage tanks’ at the weekend, and you are always free to have a mid-week carb spike if you feel your workouts are beginning to suffer towards the end of the working week.

Onwards & Upwards Friends!

Mark McManus

{ 13 comments }

1 justin June 23, 2008 at 7:37 pm: Mark,

From what I’ve read, using post-workout carbs greatly increases the effectiveness of creatine monohydrate as a post-workout supplement. What are your thoughts on this?
2 Mark McManus June 23, 2008 at 8:05 pm: Hi Justin.
This is based on the fact that insulin aids the transport of creatine into skeletal muscle.
Actually, whey protein and/or amino acids can perform this job well enough on their own without the carbs. Because of the impact whey can have on insulin, I keep my shakes to 1 per day (post-workout) with the odd exception of a pre-workout shake from time to time.
It is actually preferable to use whey as the means of increasing insulin at this time as the carbs would reduce growth hormone and IGF-1 levels, whereas protein actually works to increase these at the same time as elevating protein synthesis. You therefore get a more pronounced anabolic effect with the protein and creatine combo.
Hope that helps,
Mark
3 Gazo June 23, 2008 at 9:04 pm: Hi mark
Will a post work out help repair muscle if requird because my body is feeling rather shredded . I dont want to miss a training session because secondary muscles are still sore I been eating heaps of fish, meat cheese not so much eggs cooked but I blitz a couple in a blender with a shake in the morning things like that, but i feel my body still needs more so any advise would be great cheers mate.
Gazo
4 Mark McManus June 23, 2008 at 9:10 pm: Yes a post-workout shake starts the repair process straight away Gazo.
Mark
5 Gazo June 23, 2008 at 9:17 pm: Ill have one now then thanks Mark keep up the brilliant work.
Gazo
6 Dusty June 24, 2008 at 1:16 am: I have also read a study that showed regular whey protein alone, post workout, has been proven to be more effective than whey protein with sucrose or dextrose added. I dropped PWO carbs a while ago. I feel better since I’ve stopped taking them PWO as well.

Dusty
7 Adam June 24, 2008 at 2:48 am: So final decision is to ditch the workout carbs? And also, should I shift around my meal plan so that the carbs are still split 50/50 for before/after the workout?
8 Mark McManus July 6, 2008 at 9:48 pm: Adam, yes. Suit yourself on this, it’s completely up to what works best for you.
Mark
9 Nozza July 11, 2008 at 8:37 am: Since the study, as described, has no control group NOT taking post-workout protein. How does the author come to the conclusion that specific post-workout protein aids muscle synthesis?
10 Chas August 5, 2008 at 7:13 pm: Mark,
In regards to Post workout Carbs on Friday which would be the day to start the Carb up period. How long after the workout should I wait to start the carb up period?
11 Alex February 5, 2009 at 10:39 pm: “In 2001, Folch N. Peronnet F, Massicotte D Dulcos M, Lavoie C, and Hillaire-Marcel C. (9) showed that proficient consumption of carbohydrate sources post-workout can actually increase fat-burning and simultaneously increase recovery rates. ”
There’s quite a few more studies similar to this out their, but saying that carbohydrate consumption post workout will dramatically decrease fat oxidation is a statement based on little factual evidence.
12 Karan April 25, 2009 at 1:38 am: Hey Mark,

This looks and sounds great. But what ensures that without carbs throughout the week, that there will be enough energy? I’m a vegetarian on top of that so I am not sure how good MANS will be for me
13 troy June 11, 2009 at 9:08 pm: were you a skinny guy who wanted to build muscle? or an out-of-shape fat guy who lost weight AND built muscle at the same time. do you have “before” pictures?