Simple Carbs Post-Workout For Muscle Protein Synthesis?

If you’ve been following my posts the last month you have noticed a bit of a theme, everything is related to muscle protein synthesis. It has unintentionally in a way become a bit of a series. If you are someone who is trying to maximize muscle gains, increasing protein synthesis is of great benefit to you. As I’ve been promising for a couple of weeks now, this week we are going to look at utilizing carbs along with your protein post-workout and if this does in fact increase protein synthesis. You probably heard that taking simple carbs post-workout will help shuttle the nutrients to your muscles faster, help the recovery process and in turn give you a better anabolic response. I think it’s time to get to the bottom of this mystery.

As we learned last week whey protein and BCAAs are highly anabolic in the recovery stages after anaerobic training. I’m sure you already knew this. What we want to know now is if we can get an even better response if we add carbs to our post-workout drink. A study done in 2011 at McMaster University tested nine men who performed two unilateral knee extension trials followed by consumption of 25 grams of whey protein or 25 grams of whey protein plus 50 grams of maltodextrin. They measured both muscle-protein breakdown and muscle-protein synthesis. The results showed there was no difference between the two groups and thus concluded that insulin is not additive or synergistic to rates of muscle-protein synthesis or muscle-protein breakdown when carbs are co-ingested with a dose of protein that maximally stimulates rates of muscle protein synthesis.

An article published in the American Journal of Physiology showed similar results. 10 healthy men were assigned to three crossover experiments. They resistance trained for an hour and were given either protein only, protein plus low amounts of carbohydrates or protein plus high amounts of carbohydrates. According to their results whole body protein breakdown, oxidation, and synthesis rates did not differ between treatments. They concluded co-ingestion of carbohydrate during recovery does not further stimulate post-exercise muscle protein synthesis when ample protein is ingested.

It sounds pretty cut and dry, adding carbohydrates does not increase muscle-protein synthesis when combined with protein, end of article right? Not so fast. You have to look a little deeper into the research. Researchers may have stated there was no difference, but they concluded that because there was no significant statistical difference. When you look closer, there actually was a difference, though it was small. When you look at the actual results protein synthesis was increased by about five percent when carbs were taken along with protein rather than protein alone after resistance training. So while it may not be a significant difference, it’s worth noting there is a difference. We all know how difficult building muscle can be, so it may make sense to take every advantage you can get, no matter how small it may be. Five percent may sound like a small number, but when you increase protein synthesis by five percent for a year, two years, five years, suddenly you could be talking about a pretty big difference.

Now I want to take a look at insulin and talk about whether or not it is anabolic. Looking at some more research, the University of Illinois did a study where subjects were given either a pure carbohydrate meal, a complete meal of all macros or a placebo. Both the placebo and the carbohydrate meal did not stimulate protein synthesis while the complete meal did. In a different study done at the University of Texas compared two groups, one who took 100 grams of carbohydrates after resistance training and one who took a placebo. Net muscle protein balance between synthesis and breakdown did not change in the placebo group while it did improve slightly in the carbohydrate group. The improved net balance was due primarily to a progressive decrease in muscle-protein breakdown. It was a minor amount, but there was a difference and it was not related to muscle-protein synthesis. From everything I’ve read carbs and insulin on their own do not increase protein synthesis and thus are not anabolic, but they do play a role in minimizing protein breakdown. Since muscle growth occurs when muscle-protein synthesis is greater than muscle-protein breakdown, carbs can still play a role even though they aren’t anabolic.

The topic of insulin being anabolic is a strange one. I can search and find many articles about how anabolic it really is. I even came across one by a certain well-known person in the bodybuilding industry talking about insulin being highly anabolic and he went as far to say “without the help of insulin the protein in your post-workout shake would never get delivered.” Really? That’s not what the research shows, of course that article had no data to back it up. Since the research clearly shows insulin is not anabolic, it makes you wonder where the information about insulin being anabolic came from doesn’t it? Well insulin actually can be anabolic. Do I have your thoroughly confused yet? Don’t worry I’ll clear this all up. It is only anabolic under supraphysiological conditions, much like you hear of with bodybuilders who regularly inject high amounts of insulin that one could never come close to getting from regular feeding no matter how much you ate. Insulin can also be anabolic if you have deficient levels of insulin. Under normal physiological conditions, however, it most certainly is not anabolic.

Okay back to adding carbs in your post-workout shake. Whether you want to add them or not is totally up to you. There is no wrong answer here and it’s all based on your goals and what you are willing to sacrifice for muscle. We know that carbs do not play a major role in assisting with muscle-protein synthesis post-workout but they may aid ever so slightly. Do you want as much muscle as possible? Do you want to lean out as much as possible? Certainly if you add simple carbs you are more likely to gain a little fat as well. There is the hope that your muscles will take up most of the carbs to replenish the glycogen stores they lost from training. Like with everything there is a trade-off.

If you do decide to add carbs post-workout, how much should you add? It’s looking like the high amounts you may have heard about are not necessary either. Glynn et al. (2010) showed that when subjects were given either 30 grams or 70 grams of carbs net protein balance did not differ. In another study out of the University of Texas they gave 30 grams or 90 grams of glucose to subjects post-workout and again the same thing, no difference. Add to that what we already learned about from the American Journal of Physiology I’d say no more than 30 grams are necessary. Any more and you won’t get a greater anabolic response and you are just adding more simple carbs to your diet, which if they aren’t going towards muscle, you know where they’ll probably end up.

I briefly mentioned there is the issue of replenishing your glycogen stores. Surely you need those simple carbs to replenish glycogen stores right? Well, maybe. This is really the only way carbs help make your muscles bigger, by assisting in storing glycogen. To me as long as you are eating carbohydrates throughout the day you aren’t going to have any issues replacing those glycogen levels. You don’t need simple carbs right after your workout to make this happen. Simply eating a normal meal after your workout will easily replenish your glycogen stores. If you happen to be in a muscle-building stage chances are you are taking in a lot of carbs as it is and you aren’t going to need to worry much about topping off those glycogen levels.

There you have it, the choice is yours. If you want my opinion, whether you are adding simple carbs to a shake or simply eating carbs with a meal post-workout you’ll be fine. As someone who is currently in a muscle-building phase, if I’m doing a protein shake post-workout I take in 30 grams of carbs from pure maple syrup as well. If I’m eating a meal I don’t worry about the shake or the simple carbs, I just eat.

Happy Lifting!

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