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Post Workout Nutrition: Carbohydrate Intake

September 1, 2011

The long awaited part 2 of the Post-Workout Nutrition article has finally arrived !!!! Check out Part 1 on Post-Workout Protein Intake

Carbohydrate Intake

*Something important to consider when reading is that this specific article is designed for carbohydrate intake following resistance training. Different factors need to be considered before/during/after sporting events, endurance exercise, and low intensity exercise (yoga, zoomba and the like). Another important fact to note is this is designed for healthy individuals, and those with health concerns, especially when blood sugar needs to be monitored, may not want to follow these guidelines.

Busting the Myths of Post-Workout Carbohydrates

As you may have noticed, one of my favorite things to do, is bash on the people at the gym who spit tons of false information. As I understand this may be offensive to some, so I will refrain from this type of bludgeoning  . . . AFTER this article. Muahahaha. Carbohydrate intake is another area where LOADS of false information is spewed day in and day out in not only gyms, and websites, but trusted magazine articles as well. The general stipulation is that mass amounts of carbohydrates should be consumed directly after workouts to promote muscle growth. As with all good false information, there is some truth behind the concept. Carbohydrate ingestion, especially high glycemic index carbodydrats [link]The Glycemic Index[/link], causes a rise in blood sugar levels. The body in turn responds by releasing insulin out of the beta cells of the pancreas, which bring blood sugar back down to normal levels. Insulin has also been shown to have an anabolic (muscle building) effect in tissues.  Following this line of thinking, you can see why so many blindly believe that mass loads of carbohydrates after a workout is needed to promote the best muscle growth.

Is there evidence? Possibly …

Several studies have shown that carbohydrate ingestion after a workout reduces protein breakdown. (Miller 2003) Remember that ultimate muscle growth is an equation: (protein synthesis minus protein breakdown = muscle growth) So, in theory we consume protein to enhance muscle protein synthesis, and carbohydrates to reduce breakdown. That would yield the greatest muscle growth. However, it appears that may not be the case.

A study by Glynn et al in 2010 offers insight into the possible benefits of different levels of carbohydrate consumption after resistance training. Utilizing 13 male subjects the study design involved a resistance training session followed by 2 difference nutrient formulas. One group received an protein along with a low carbohydrate content (30 grams), and the other received the same protein, but with a high carbohydrate content (90 grams). The study looked to measure rates of muscle protein breakdown (MPB-muscle loss) and muscle protein synthesis (MPS-muscle growth)

Basic Overview

– 2 groups: 1 gets a protein and low carb drink, 1 gets a protein and high carb drink

– Measuring both aspects of muscle growth: breakdown and synthesis

– Looking to increase synthesis and reduce breakdown for best muscle growth

The main findings in the study were that no difference in protein synthesis was seen between the low carbohydrate and high carbohydrate groups. Just looking at this aspect we can see that small and large amounts of carbohydrates provide the same muscle growth benefits as long as protein is taken. Beyond NO enhanced protein synthesis, NO difference was seen in reducing protein breakdown among the groups. Again, there seems to be no additional muscle growth benefit between small and large amounts of carbohydrates after a workout. Now this begs the question …

Do We Need Post-Workout Carbs at All?

Staples and colleagues recently completed a study comparing the effects of 2 drinks on rates of protein synthesis and breakdown both after workouts and while resting. The drinks used contained either 25 grams protein, or 25 grams protein and 50 grams carbohydrates. Interestingly, the results, both for after workouts and resting, showed there was NO difference in the rates of protein breakdown or synthesis between the groups. (Staples 2010)

It appears that the previously documented benefits of carbohydrates after workout are NOT additive to the effects of proper protein ingestion. This may be due to the fact that protein ingestion has the ability to stimulate insulin release enough to maximize protein synthesis independently from carbohydrate ingestion. Although carbohydrates seem to provide no benefit in terms of muscle growth after exercise, proper daily carbohydrate ingestion is necessary for best performance in the gym, and carbohydrate consumption after workouts certainly will not inhibit your muscle growth goals. Look forward to future articles on carbohydrates for various people, training, and goals, as carbohydrate ingestion is a complex topic with no one universal answer.

Piece of Cake … Nutrition:

– Carbohydrate ingestion after workouts provides no additional muscle growth benefits as long as proper amounts of protein are consumed.

– However, carbohydrates may offer other benefits and should not be removed from your post workout routine if you have goals other than lean muscle growth.

References:

Glynn Et Al. “Muscle Protein Breakdown Has a Minor Role in the Protein Anabolic Response to Essential Amino Acid and Carbohydrate Intake following Resistance Exercise.” Am J Physiol Regul Integr Comp Physiol 299 (2010): 533-40. PubMed. Web. Fall 2010.

Miller, Sharon L., Kevin D. Tipton, David L. Chinkes, Steven E. Wolf, and Robert R. Wolfe. “Independent and Combined Effects of Amino Acids and Glucose after Resistance Exercise.” Medicine & Science in Sports & Exercise 35.3 (2003): 449-55. Web.

Staples, Aaron W., Nicholas A. Burd, Daniel W.D. West, Katharine D. Currie, Philip J. Atherton, Daniel R. Moore, Michael J. Rennie, Maureen J. MacDonald, Steven K. Baker, and Stuart M. Phillips. “Carbohydrate Does Not Augment Exercise-Induced Protein Accretion versus Protein Alone.” Medicine & Science in Sports & Exercise(2011): 1. Cleveland Clinic Libraries. Web.

One Comment leave one →
  1. Mey Rick permalink
    September 2, 2011 7:03 AM

    Nice one, guess I can quit eating the entire pizza after my work-outs now!

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