Post-workout carbohydrates: are you drinking tons of sugar for nothing?

There are two kinds of people in the fitness industry: those who advise and motivate you to buy their products, and those who advise you, because you paid them for it.

Well in truth maybe it's just the cynic in me speaking! Cynicism can still be a good thing though - it keeps you objective. And that's exactly what we're going to do in this article. We're going to take an unbiased look at the effects of consuming carbohydrates before and after your workouts.

Should you consume carbohydrates after training?

Suppose you consumed a carbohydrate shake after your workout without any protein. This kind of snacking has been the subject of much research, and low doses (eg 6g) of carbohydrate do not increase the net protein balance after training. Of course, 6g is next to nothing. Maybe it would just take a little more to see an effect? Bürsheim et al. (2004) have therefore tested this hypothesis. In their study, subjects were given either a placebo or a post-workout shake containing 100g of maltodextrin. The result: protein synthesis did not improve, but protein degradation decreased, resulting in a significant increase in protein balance. However, the effect was "minor and delayed" and the protein balance was still negative. In the same vein, Glynn et al. (2010) have shown that 70g of carbohydrate does not affect protein balance more than 30, so if you are going to consume carbohydrates, 30 grams should probably be your upper limit. Glynn et al. also concluded, in their review of the literature, that a high protein balance after consuming a post-workout shake is almost always due to increased protein synthesis caused by protein ingestion "with minor changes in protein breakdown muscle, regardless of carbohydrate dose or circulating insulin level. (Note that they did not look at the casein case.)

But after all, if carbohydrates help reduce even a tiny bit of protein breakdown, it can still be better than nothing… right?

Another review of the workout nutrition literature concluded that studies where only protein was administered found an increase in protein balance "to a similar degree to studies conducted previously that used a combination of acids. essential amino and carbohydrate ”. In addition, "a small dose of amino acids after a weight training session has been shown to stimulate similar changes in protein synthesis and protein balance [...] with or without carbohydrates." (My emphasis here: Kerksick and Leutholtz, 2005 ). In conclusion, carbohydrates can reduce protein breakdown a bit when you only consume the latter, but if you are already consuming protein, the carbohydrates have little or no additional effect.

Now there are two studies ( Miller et al. 2003 ; Bird et al. 2006 ) which show that adding 35g of carbohydrate to 6g of protein increases the net protein balance, suggesting that carbohydrates may have an effect. additional. It's hard to understand why this stupid protocol has been reproduced several times in research, but let's agree here to contemplate the idea for a moment. These studies used the same experimental design as the study by Rasmussen et al. (2000), and the results contradict each other. According to this latest study, "the breakdown of muscle protein has not changed." Protein stimulated protein synthesis, but carbohydrates by no means amplified the effect of protein. In addition, the subjects of the study by Miller et al. were absolutely brutalized and malnourished. After a fast, they had to do 10 sets of 8 reps at 80% of their 1RM on the leg press, then 8 × 8 at 80% of their 1RM on the leg extension. To get an idea of ​​how violent the protocol is, it's like doing a German Volume Training session at a higher intensity and going to muscle failure with each set. Then, in order to “recover”, they received 6 g of protein and 35 g of carbohydrates. If there is a situation in which carbohydrates, or anything that gives you some form of energy, can possibly help you recover, it is this. And even in such a case, only 1 of 2 studies found an additional positive effect of carbohydrates.

Koopman et al. (2007) used a much more relevant study design. They looked at differences in protein balance in groups consuming 0, 0.15, or 0.6 g of carbohydrate per kg of body weight when ingested with about 25 g of protein after resistance training. Their results? “Whole body protein degradation, synthesis and oxidation rates, as well as whole body protein balance, showed no difference between the experiments. […] In conclusion, co-ingestion of carbohydrates during recovery does not further stimulate muscle protein synthesis after exercise when a sufficient amount of protein is ingested.

Staples et al. (2011) wanted to reproduce the above conclusion to end the discussion once and for all. After a weight training session, they gave their subjects either 25g of whey or 25g of whey in combination with 50g of maltodextrin. They found that consuming 50g of maltodextrin with 25g of whey did not stimulate muscle protein synthesis or inhibit protein breakdown more than 25g of whey alone.

The most important aspect of the above two studies compared to previous studies was the presence of at least a semi-respectable dose of protein. So to conclude, carbohydrates potentially inhibit protein breakdown only in extreme circumstances where insufficient amount of protein is ingested. Unless you destroy a muscle with 18 sets pushed to failure after a long fast and consume no more than 6g of protein, carbohydrates add nothing to the effect of protein.

Now, you might be reluctant to believe all of this. Of course, it's no fun to find out that you've intentionally added tons of sugar to your post-workout shakes for no good reason. The classic theory of bodybuilders (read: broscience) is that carbohydrates trigger an insulin spike, which then helps transport all the protein inside your muscles. Translated into statistical terms, this would mean that there is a positive interaction effect between protein and carbohydrate on net protein synthesis. This hypothesis is not supported by any research, and is found to be explicitly denied by the research of Miller et al . and Staples et al. As with many theories in the fitness industry, things can often seem plausible, but there is enough empirical evidence to show that this is wrong. Such simplistic theories ignore the many complexities of the human body. Your body doesn't need carbohydrates to process protein. In fact, your body doesn't really need carbohydrates for anything.

Of course, there are certain scenarios in which carbs can be useful, such as a carb refill (eg as part of pre-competition / water manipulation). However, during a classic mass gain, carbohydrates do not add anything to the effect of proteins. Plus, the best diet is always the one that maximizes the amount of beneficial nutrients you take in, given your calorie constraints. Since dextrose, maltodextrin and other stews like Waxy Maize Starch are virtually devoid of nutrients and moreover very caloric, they have no place in an optimal diet for health. Instead, your carbs should come from vegetables, fruits, and foods like quinoa,

But then, what about glycogen resynthesis?

Even though the classic carbohydrates used in bodybuilding circles don't increase protein balance or provide quality nutrients, they might still be needed to preserve or replenish glycogen stores, right? ?

First, you have to achieve a literally absurd amount of work volume to truly deplete your glycogen stores during a weight training session. A full body workout consisting of 3 sets of 9 exercises each at 80% 1RM only depletes about a third of the body's glycogen stores and 9 sets on a specific muscle group results in only 36% exhaustion in that group. muscle ( Roy et al. 2000 ). After performing sets of 6 at the leg extension at 70% of 1RM until absolute failure occurred (one of the strangest protocols I know of) and consuming nothing afterwards, 75% of Glycogen stocks in the subjects of this study were restored after 6h ( Pascoe et al. 1993). In addition, the body regulates itself adequately. The more you deplete glycogen, the faster the glycogen resynthesis. The higher the intensity of the effort, the faster the resynthesis. The greater the exhaustion, the more glycogen the body stores for the next time. Even in endurance athletes, glycogen resynthesis is often complete after 24 hours. You would have to train a muscle twice a day with a volume that you cannot recover in order to need the carbs to replenish your glycogen stores in time for the next workout. And if you ever had to completely deplete your glycogen stores, you would know it, because endurance athletes say it's like suddenly being absolutely unable to move.

Origin of the post-workout carbohydrate myth

So how come the myth that you need carbs in your post-workout shakes is so common? There are several reasons for this:

• The manufacturers of dietary supplements want you to believe that you need carbohydrates because carbohydrates are extremely cheap to produce. For example, virtually all "gainers" are in fact made mostly of sugar sold at a ridiculous price.
• Many people only read research that only looks at carbohydrates, not realizing that protein makes carbohydrates completely redundant for protein synthesis.
• The literature advocating carbohydrates for endurance athletes can easily be misinterpreted by people who only read the summaries.
• Many myths are perpetuated for no logical reason, each spreading the word simply because everyone else is spreading it as well. * insert a sheep bleat here *
• Many professional bodybuilders inject themselves with insulin after training. This requires the consumption of a large amount of carbohydrates to avoid falling into true hypoglycemia. But without exogenous insulin and steroids, unnecessary excess carbohydrates are more likely to turn into fat than muscle.

Verdict on post-workout carbohydrates

So you don't need to consume carbohydrates after your workouts. When enough protein is ingested, carbohydrates have no additional effect on protein balance. You don't have to avoid carbs at all costs, but adding sugar to your post-workout shakes is like adding sugar to any of your other meals. Not necessarily the best idea for optimizing your nutrition.

Adding that to your post-workout shaker won't double your biceps.

Related research and references:

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1. Bayesian France training / MennoHenselmans.com