One of the most popular myths is that it is critical to eat non-fiber carbohydrates following a strength training workout in order to elevate insulin to maximize muscle growth. Non-fiber carbs consist of sugars and starches and definitely do increase insulin levels, but is this really necessary to build muscle? The answer seems to be no. A recent study* showed that there was no difference in protein synthesis in muscle when 25 grams of whey protein or the same amount of whey protein with 50 grams of carbs where ingested after strength training.
Increasing insulin (which drives storage in muscle AND fat cells) does have a protective effect on muscle degradation, but this can be achieved without the extra insulin from carbs! This is really significant if you are trying to gain muscle WITHOUT increasing bodyfat.
Now if you are serious athlete training multiple times a day, taking in more non-fiber carbs will enhance glycogen levels in the muscles (glycogen is simply multiple units of glucose linked together). Glucose is a key energy source for muscles, and for athletes that train intensely and frequently it can be the difference between success and failure.
For the rest of us mere mortals ingesting higher levels of carbs simply drives more fat production and is not a good idea even post workout. So the bottom line is that there is no need to take in carbs post workout to build muscle mass, and if you want increased muscle mass without increased bodyfat 20 grams of whey protein post exercise along with a normal diet will provide all your muscles need to grow!
· * http://www.ncbi.nlm.nih.gov/pubmed/21131864