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