Is carb loading or carb-refeeding necessary for big muscles?

In every circle of body builders and body science experts there are folks trying to find shortcuts for getting bigger and stronger in less time. Protein timing, meal timing, workout timing, carbo-loading, etc, it’s all scrutinized and debated into the ground.

One of the most common things you’ll hear is that carbohydrates after exercise is “absolutely necessary for protein synthesis”, or that “carbohydrates increase protein synthesis beyond what can be achieved with protein supplementation alone”.

What’s the reason for this belief? I think a lot of it stems from conventional wisdom. You know, that driving force that keeps everyone following the USDA dietary guidelines, stuffing themselves with cheap sugar calories in the form of bagels, pasta, and “hearthealthywholegrains” (they do form the base of the food pyramid, by the way).

Another driving force is the fitness and health industry, people who are licensed to parrot that conventional wisdom to anyone who is willing to pay for their “training advice”. Most of the things that are taught through personal trainer licensing programs and dietitian programs, etc, teach these people basic weighing and measuring of carbs-protein-fats. They even teach them formulas to calculate the exact amount of carbs you will need for your given activity level. This, again, makes carbs appear to be a necessary part of our lives.

The final and possibly most influential force in the belief that carbs are needed for big muscles? The big-muscle guys themselves. Again, it’s merely conventional wisdom rearing its ugly head. Something so basic and incorrect can be repeated a million times by huge influential dudes in the community, and that thing suddenly becomes truth, because it’s been repeated over and over. But where’s the proof?

I think one thing that drives people to accept this theory lies in the fact that carbs (and sugar) cause a spike in insulin secretion. Insulin is a growth hormone that forces nutrients into cells (as long as you aren’t insulin resistant like most Americans). Forcing nutrients into cells is what body builders want, because it initiates growth and repair of damaged muscle tissue. That’s exactly how you get bigger muscles, faster.

But wait, is that all there is to it?

Did you know that protein initiates an equal, if not larger amount of insulin to be secreted compared to carbohydrates? That’s pretty interesting to know, because that fact by itself disproves the idea that carbs are required because of the insulin effect. Given enough protein ingestion, there will be plenty of insulin response to get your tissues growing.

Now, what about replenishing those lost glycogen stores after our brutal workout?

Well, if you are already eating a Paleo type diet, high in vegetables, starchy tubers, and some fruit, your daily diet will supply enough “carbs” to easily refuel your lost glycogen. It can even be replenished across a few days. Your liver even takes care of this via gluconeogenesis if you are on a very low carb diet.

And, if you are sticking to a fairly moderate exercise plan, about 3 times per week and no longer than an hour each, there is no need to “carb up” so rapidly, since you really aren’t draining your glycogen stores that much. If you are doing lots of HIIT (more than once or twice a week) or you are an endurance athlete, this changes a bit, as you may want to have more carbs in your diet, but I’m not talking to you marathoners right now.

There is one caveat to all this carb loading stuff. If you are doing occasional carb-refeeds or some sort of other carb-cycling protocol like Leangains to get rid of that last few percentages of stubborn body fat. There is a time and a place for that, but it really does not relate to the purpose of this discussion (which is whether or not carbs are required for protein synthesis or increased protein synthesis).

Bottom line, carb-refeeding or cab-loading is not necessary, and carbs are not required, for normal or increased protein synthesis.

Let’s look at the proof.

Here is a study that looked at just that. They compared protein synthesis post workout after ingestion of 20 grams of protein. They then compared it with the same amount of protein+some carbohydrates. The outcome? Nada. None. No difference in protein synthesis.

This study looked at the difference in protein synthesis and growth hormones after consumption of protein OR carbohydrate, and strangely enough, found no difference in protein synthesis versus consumption of just protein or just carbs. They did not state whether or not the subjects had fasted before hand, so they very well could have already eaten and had some amount of amino acids already floating around in their blood, waiting to be used. This seems to suggest that had you eaten at all that day, eating anything at all after workout will stimulate a similar amount of growth. Huh!

This last study can be confusing because of their wording. They tried to make it appear that carbs were necessary to facilitate increased protein synthesis. The problem is, they were comparing Protein+Carbs to Carbs only. The protein+carbs group had a higher myofibrillar, but not mitochondrial protein synthesis. And the amount of carbs in both groups was small at 25g. Having more grams total in the P+C group is likely the major contributing component.

Edit 4/18/12: Also, another reason that carbs are not required to fuel muscle building!Branched chain amino acids, which are found natrually in the protein of animal products and also as a workout supplement off the shelf, can convert to glucose as your body demands. This is great for those of us who do fasted training, because taking BCAA’s pre workout will stop our bodies from breaking down precious muscle mass to produce glucose for fuel. It’s the isoleucine and valine that convert to glucose, while leucine converts to ketones. So there is absolutely no need to consume “carbs” before or after workout to prevent muscle breakdown!

So there you have it. Carbs necessary for protein synthesis or body building? Nope! Just get plenty of protein and nutrients, and you’re golden!

Like this post? Leave a comment!

Want to find out more about how to get in shape fast? Check out these articles about getting in shape, feeling great, and controlling your genes!

Lower bodyfat setpoint.

Lose stubborn body fat. (Intermittent fasting)

Control your gene expression.



Why you should avoid too many polyunsaturated fats.

What is chronic inflammation. What to eat to avoid it.

The final word on grains and legumes: AVOID them.

The final word on Saturated fat and Cholesterol: EAT them


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