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Carbs Not Required for Your Workout Protein Shake

December 19 2010

The belief that carbs are required in your post workout protein shake is so established that the debate has been more about whether to take high gi or low gi carbs, if waxy maize is better than dextrose. and so on. But this recent study shows that carbs may not be required in the first place.

carbs post workout protein shake

Why carbs were needed in your workout protein shake?

Protein break down: Protein breakdown is increased after workouts. Carbs increase insulin levels and can blunt protein breakdown after your workouts. This is the major reason why carbs are added with protein shakes.

Protein Synthesis: Carbs can increase insulin levels and slightly increase protein synthesis.

Glycogen: Restore glycogen in the muscle. Unless you are doing a lot of high reps, glycogen is not really depleted with weight training.

What was the study design?

  • 9 recreationally active subjects were randomly assigned to a Protein only group and a protein + carbs group.
  • Participants performed 2 trials seperated by 7 days of 4 sets of leg extensions (8-12) for failure after an overnight fast.
  • The protein group consumed 25 gms of whey protein while the protein+carbs group consumed the protein with 50 gms of malto dextrin

What were the results of the study?

  • As predicted, the glucose and insulin levels was significantly greater for the protein+carbs group
  • But, guess what, there was no difference in protein synthesis or protein breakdown between the protein only group and the protein plus carbs group.

Are there other studies to support?

30 gms vs 90 gms: Another recent study looked if 90 gms of carbs +amino acids can decrease protein breakdown compared to 30gms+amino acids after resistance training. But they didn’t find any significant difference between the groups.

Though study lacked a group with only protein to see if there is any difference if only protein was ingested, the results are consistent with this study.

Practical Applications

  • There is no reason to add carbs in your post workout shake to decrease protein breakdown or increase protein synthesis.
  • The protein itself in the shake is enough to increase insulin levels and decrease protein breakdown to the maximum extent

Reference 1
Reference 2


How Much Protein Do You need After Your Workout?
Is Exercise or Cardio Exaggerated in Losing Weight?

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pt30 | Mon December 20, 2010  

I’m interested to see more information on this because this conclusion is based upon the testing of only 9 male subjects.  What other(if any) ratios of Carbs to proteins were tested?  How soon post-workout were these shakes consumed?

I’m not asking these questions to be a pain as I’m glad that you are out there testing your theories.

Anoop | Tue December 21, 2010  

Hi Pt30,

Thanks for the comment.

Good question. First it is a cross over design so the control and treatment group are the same so you need much less subjects than usual.Also this type of design minimizes the external variables like genetics and motivation.

And they did a power analysis and for a 25% difference in mean, 9 subjects were enough. I am surprised they did one considering they didn’t do for the previous studies.

About the ratio: The ratio doesn’t matter. The whole point is to raise your insulin levels and it was significantly raised to around 40% more than the protein group.

They consumed the drink 15min post exercise.

I sometimes don’t go into the details in the article just because not many bother to read it, and it gets too long. I expect someone to ask these like you.

Now if someone comes and does a long term study and shows a difference in muscle and strength, that will trump this one. But it is unlikely.

bj | Thu December 23, 2010  

Remember when it comes to muscles growth that if you go to low in carbs your body will eventually start breaking down protein thus muscle.If I was to supplement I would make my shakes out of whey and milk full fat as this provides a massive dose of protein and carbs perfect after workout snack.

Anoop | Thu December 23, 2010  

Hi Bj,

Thanks for the comment.

It doesn’t mean that you will only grow muscles if you eat carbs after your workout. You can have carbs any other time during the day and still be fine.

This is something so established int he bodybuilding community that people take 50-75 gms of dextrose and stuff after their workouts. There has been debates lasting several pages about whether they should take waxy maize or oats. It seems like carbs are not that important, let alone the type of carbs.

I can see the volume here being less than what most people do. But since they came fasted which is uncommon in real life, it kind of balances it out. If you are bulking for sure, I don’t see any point for further carbs after the workout. And it is better to eat some quality carbs than just drink sugar which no other benefits.

FullDeplex | Thu December 23, 2010  

I think it is fantastic how you question the established “facts”. Keep it up!

bj: I doubt that low carbs will eventually cause the body to break down muscle. It may do this in combination with long term calorie deficit, but I haven’t seen any studies that show that low carbs cause muscle break down. Could you please post some studies that show this effect?

In the meanwhile…

Here is a study you guys might find interesting too about this subject: http://jcem.endojournals.org/cgi/reprint/90/9/5175

Too bad this was only a 9 day study and they did not workout. The effect may have been only temporarily.

Anoop | Fri December 24, 2010  

Thanks FullDeplex!

In the exercise field, most of the evidence is anecdotal or theoretical. And more often than not, they are wrong when tested experimentally.

And it is not conclusive that carbs will not make a difference unless there is a long term study.But the evidence is heavily leaning towards no effect. There is a long term study which shows better results with carbs+amino’s, but they didn’t control the calories for the groups which will show up in long term.

Karky | Fri December 24, 2010  

“Thanks Karky!” I haven’t even commented on this :p
I’ll just consider it a thanks for being generally awesome :D

Anoop | Sat December 25, 2010  

Since it is Christmas, you can keep it and you are awesome.

Karky | Sun December 26, 2010  

You’re awesome too, and this is an awesome site!

Dale | Thu March 31, 2011  

Now the next question is, is the protein necessary ? I’ve known folks who’ve grown and gotten stronger with it and plenty who’ve grown and gotten stronger without it.

Anoop | Thu March 31, 2011  

Hi Dale,

That is just a correlation. I know many black people who are bigger even without lifting you know.

I think we have some biological plausibility and acute and long term studies showing that protein is useful after your workouts. How useful? Depends on the population and what your goals and such.

Does it make sense, Dale?

Dale | Thu March 31, 2011  

Hi Anoop -

Of course it does. Unfortunately, I know my fair share of protein cultists. They might agree with this recent finding on the carbs. But they’d storm the gate if you tried to take their protein away!

Hey, I tell them to take their protein. What’s the harm ? But their prescriptions are often ridiculous, often 2g per pound of bodyweight and two shakes per day, even when attempting to reduce weight!

Kathleen | Sun August 14, 2011  

Hi Anoop,

But are there reasons other than blunting protein breakdown and increasing protein synthesis to take carbs post-workout? Isn’t cortisol high after a workout, and wouldn’t carbs+protein bring down cortisol faster than protein alone? Cortisol is catabolic, no? So wouldn’t addressing this and possibly other hormonal issues, eg, carbs’ effects on testosterone, be worth considering?


Anoop | Sun August 14, 2011  

Hi Kathleen,

Good question, and yes. Lowering cortsiol and refueling glycogen reserves are the other reasons. One of the main reasons was decreasing protein breakdown though. In the recent NSCA conference, Dr. Jeffery Stout recommends a 2:1 ration than the usual 4:1 ration of carb to protein ratio mainly because of this study.

highstandards | Sun November 27, 2011  

But do we really need to refuel our glycogen reserves after a 60 minutes strength training workout?

Anoop | Mon November 28, 2011  

Depends on your carb intake and your workout. If you do not consume too much carbs, if you are doing a high volume workout, carbs after weight training may be good. The ratio was 1:4 for post workout which was too much carbs. 1:2 may be enough

Carbs also help lower cortisol and increase glycogen, but I am not sure how much it will help in muscle growth. We didn’t see it as increased protein synthesis or decreased breakdown anyhow.

highstandards | Mon November 28, 2011  

Since I take carbs at most of my meals during the day and train in the evening, I should have enough to go through the workouts. I’m going to only add some dextrose to my shake when I add creatine to it.

Sunil | Fri March 16, 2012  

Dear Anoop,

Very nice article where he says consume whey protein every 3hrs and also recommend to consume carbo..

Which expert to listen,we are confuse….


Anoop | Fri March 16, 2012  

Hi Sunil,

What is your question?

It is probably good to have some carbs because the muscles are primed to take up carbs after exercise. But there is no reason to add large amount of carbs carbs to inhibit protein breakdown or increase protein synthesis as we thought.

That interview was done in 2009. this study was done in 2010. Make sense?

Stu | Mon October 08, 2012  

I think this is a pretty accurate assessment with the excess of carbohydrates when doing a strength based workout (lifting weights).

From reading the article alone it sounds like you’re recommending no carbohydrates at all but from your comments it sounds like you’re a proponent of adding in carbohydrates, just not as much as some people do.

With the sports nutrition out there, it seems like they are actually doing a 2 protein to 1 carbohydrate post workout shake which I don’t necessarily agree with. I’m more for a 1:1 after strength training and a 3:1 after glycogen depleting work.

Thanks for the article—it was a good read and good discussion!

What do you think?



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