BCAAs for Bodybuilders: Just the Science (Part 1)


Though BCAA supplementation is used by several populations with contrasting goals (e.g. bodybuilders and other aesthetic pursuits, strength athletes, the elderly or other individuals with the potential for lean body mass losses), this article will focus purely on the bodybuilder with the objectives of gaining more muscle mass, maintaining muscle mass, or maintaining muscle whilst losing fat.


What are BCAAs?

Branched-chain amino acids (BCAA) are named after their branching chemical structure and consist of the three essential amino acids: leucine, isoleucine and valine. BCAAs are one of the most popular supplements available on the market. Their popularity may rest in some part to the unique role of BCAAs, in particular, leucine, regarding the modulation of protein synthesis via the stimulation of the biochemical sensor, the mammalian target of rapamycin (mTOR). In addition to their commercial use, BCAAs have been extensively studied in a number of roles relevant to athletic performance, including: immune function, central fatigue, sparing lean body mass, attenuating markers muscle damage and promoting muscle protein synthesis (MPS). Unknown to a lot of trainees, probably due to clever marketing, is the fact that BCAAs are found in whole proteins and are often cheaper on a gram per gram basis compared to their isolated counterparts. In addition to their BCAA content, whole foods contain all the additional amino acids and offer other benefits (some potentially anabolic) that go along with them (e.g. generally better satiety, various vitamins & minerals, and therapeutic properties) (Table 1).


Table 1: BCAA and leucine content of foods

Source for data.    *Products from www.myprotein.com


From table 1, you can see that high quality proteins such as animal flesh, eggs and supplements derived from milk, contain quite a high percentage of BCAAs. On a gram per gram basis, you get more than double the amount of BCAAs for your money if you opt for a high quality whey protein isolate than if you were to purchase isolated BCAAs. As such, why would someone not just opt for a whey protein supplement if they were looking to bump up the content of protein or BCAA in their diet? After all, it would offer the same convenience (probably more so if you account for the awful taste of BCAA powders).

Is there a benefit to BCAAs?

As stated earlier, there has been a fair bit of research examining the effects of BCAA supplementation on various aspects relating to performance and body composition. Indeed, several studies have in fact shown BCAA supplementation to positively impact body composition (i.e. improve muscle gain or fat loss), support immune function and reduce markers of muscle damage. All seems good so far? Not quite. With a closer inspection of the data, these outcomes are unsurprising, as it is clear that protein is always insufficient in the first place. So essentially, what these studies are showing is that adding BCAAs to a diet containing inadequate protein (by my standards, at least), their addition may improve the dependent variable/s that the researchers are looking at.

For example, in a study often-quoted by the companies/people looking to sell BCAA supplements, Mourier et al. (1997) examined the effects of 52 g of BCAAs on body composition during three weeks of caloric restriction in a group of competitive wrestlers. In this study, the wrestlers were given a diet consisting of 28 kcal/kg/day with 20% protein. This equated to roughly 80 g of protein per day (or 1.2g/kg) for a 68 kg wrestler. It was found that the supplement group, who ingested an additional 52g of BCAAs, spared more LBM and experienced slightly greater fat losses compared to the control.

In a study published in an Italian journal, the authors compared the effects of 0.2 g/kg of BCAAs with a non-caloric placebo taken 30 minutes before and after training, on bodybuilding progress in a group of experienced drug free bodybuilders (with at least 2 years training experience). The BCAA group showed better gains in body weight, arm and leg circumference, and squat and bench press performance. So essentially, using a 90 kg athlete as an example, this study showed that adding 36 g of BCAA around a workout is better than ingesting nothing. A 'bro' could’ve told you that!

These studies are often cited as ‘proof’ that you need massive doses of BCAAs, particularly around training. I think otherwise. Firstly, the subjects in the initial study consumed insufficient protein (1.2g/kg per day). In my previous article on protein requirements, I came to the conclusion that 2.5-3 g/kg would be more appropriate for strength/power athletes. Using a 68 kg individual as an example, this would mean a protein intake of 80 g vs. 170-204 g per day, a difference of about 18-25 g of BCAA per day from whole food sources (more so, if whey were to make up a significant proportion of the added protein intake). Though it is unknown whether the wrestlers would’ve still outperformed the control group given a sufficient protein intake in the first place, I have my doubts.

Speaking of protein insufficiency, it is no surprise that a mega dose of BCAAs around training was superior to consuming nothing around training. This study by Cribb & Hayes (2006) perfectly demonstrates the importance of the provision of nutrients around training. Given a sufficient protein intake in the first place, as well as the provision of whole foods around the training bouts, it is also unknown whether the BCAA group would have outperformed the placebo control.  Specifically, since I recommend consuming 40 g of protein within a two-hour window prior to and after training (80 g total), 80 g of protein would provide roughly 15-20g of BCAAs (depending on the source) around the training bout as well as all the other amino acids. For these reasons, I also have my doubts that additional BCAA supplementation on top of my whole protein recommendations, would prove any additional benefit.

Though there is research demonstrating the benefits of BCAA supplementation regarding the promotion of muscle protein synthesis and preventing muscle protein breakdown (MPB), whether this holds true in the presence of sufficient amino acids from whole food sources remains to be properly studied. As such, given that whole protein sources such as whey are more economical than isolated BCAAs, and that the vast majority of people looking to build muscle are already consuming (with many possibly exceeding) a protein intake that I consider adequate(2.5-3 grams per kilogram of body weight), the real question we should be asking is, whether adding BCAAs to an already high protein intake will offer any benefit. Or, an additional question is whether there is something unique about isolated BCAAs. Specifically, will isolated BCAAs offer something that adding more protein from whole foods will not (i.e. does their structure or their caloric economy offer any benefits to body composition)? In the following section and in a future post, I’ll attempt to answer these vital questions.


Is a high protein intake sufficient at optimising muscle gain?

To my knowledge, no published studies have examined the effects of chronic BCAA supplementation on body composition alongside a structured resistance-training program, and in addition to an already high protein intake. Luckily, there is a study that fits these criteria, and is the only one that comes close to answering the question of whether adding BCAA to a pre-existing sufficiency of protein yields any benefit. It isn’t fully published, but is available on the ISSN website in the form of a poster presentation. Stoppani et al. (2009) examined the effects of a supplement (Xtend) containing BCAAs on body composition and strength following an eight-week resistance-training program in 36 strength-trained males with a minimum of two years weight training experience. The participants were assigned to one of three groups and were to receive one of the following, during their eight week program: 14 g BCAAs (BCAA), 28 g whey protein (WHEY) or 28 g of carbohydrate from a sports drink (CHO). The BCAA group gained 4 kg of lean mass whilst the WHEY group gained 2 kg of LBM over the course of eight weeks. For completeness, the CHO group gained 1 kg of LBM in eight weeks. In addition, the BCAA group lost 2% body fat in the eight weeks whilst the WHEY and CHO groups both lost 1% body fat. To top things off, the BCAA group gained a greater amount of 10-RM strength in the bench press (6 vs. 3 kg) and squat (11 vs. 5 kg) compared with the WHEY group.

Interestingly, these results occurred despite a habitual daily protein intake of 2.2-2.4 g/kg. At closer inspection, these results do appear to be too good to be true. Indeed, a gain of 4kg of LBM in just eight weeks, with a concomitant decrease in body fat of 2%, seems a little farfetched, especially when you consider that these subjects were drug-free, experienced weight trainees. In my articles of maximum muscular potentials, I mentioned that a novice could expect to gain about 1kg per month (assuming they get everything right training and nutrition-wise). Achieving double this amount of muscle gain in experienced trainees just doesn’t seem right. When results appear this good, I look to see who funded the study. It was in fact Scivation, the makers of the Xtend product that was tested, who funded the study. While funding does not automatically invalidate study findings (they have to get the funding from somewhere!), it may bias the results somewhat. My thoughts on the matter echo those of Alan Aragon who discussed this trial in the February 2010 issue of his monthly research review:

“The skeptic in me is tempted to chalk up some of the results to not just funding source (Scivation), but also the longstanding friendship [my link] between Jim Stoppani and the Scivation staff. The fact is, there’s no way to quantify the degree of commercial bias inherent in this trial – or any other for that matter.”

With all things considered in this trial, I find it highly unlikely that the provision of an extra 7 g of BCAA per day in the BCAA group would have outperformed the WHEY group to such an extent. As such, I would like to see similar trials conducted before recommending the addition of BCAA on top of an already sufficient protein intake.


Conclusion (for now)

To summarise so far, we have learned what BCAAs are, their unique role in protein synthesis, as well as what foods they are contained in and in what percentages (table 1). At first glance, the extravagant marketing claims and suggested protocols of usage seem to be backed by scientific research. However, as we dig a little deeper, it seems unlikely that these benefits would exist in the presence of a sufficient protein intake. Though additional BCAAs might be beneficial to bodybuilding goals (i.e. more muscle and less fat), the research has yet to show these effects. If such effects do exist, they are likely to be miniscule. Because of this, they would only be something worth considering for the elite physique athletes who are looking for that extra 1-2% to gain an advantage over their competitors. For the majority of people just looking to improve their body composition, I see them as an unnecessary expense; focusing more on what delivers (i.e. progressive strength gains in the main compound lifts in addition to a well-structured nutrition protocol) will allow them to reach their desired goals (and more). In the absence of sufficient scientific evidence, from my experiences both personally, as well as client feedback, adding BCAAs to a diet of adequate protein consumed appropriately around training, has failed to produce any noticeable benefits, despite the potential for placebo effects.

To give this topic appropriate justice, I will be splitting it into two or more parts. In subsequent posts, I will examine the research behind between-meal dosing of BCAAs (popularised by Dr. Layne Norton) and the rationale for their use whilst dieting. I will end the topic of BCAA supplementation by tying things up with an overall summary and offer my practical recommendations.

Click here for part 2.

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What is my natural muscular potential? Part 2

In part 1 of “what is my natural muscular potential?” I introduced two models of natural muscular development, which were both derived from natural bodybuilders. In this second and final part, I’ll use a real-world example and see how my stats measure up to both models. I’ll also talk about limitations to these formulae, as well as giving a brief outline of what it takes for someone to reach their muscular potential.

A real-world example

To give you an idea of what these numbers actually mean, I’ll run my own stats through both models to see how close to my genetic potential I am.

My stats:

Stature – 181 cm (5’111/3”)

Body mass – 76.5 kg (168.3 lbs.)

Body fat percentage – 8% (ish)

Lean body mass – 70.4 kg (154.8 lbs.)

Ankle circumference – 8.25”

Wrist Circumference – 6.7”

Bicep circumference – 15”

Using my stature, wrist and ankle circumferences the Casey Butt model predicted my maximal natural lean body mass to be 75.9 kg (167 lbs.).

Since my current lean body mass is roughly 70.4 kg (155 lbs.), this equates to 92-93% of my genetic potential based on this equation.

Using the Martin Berkhan model, my predicted maximal natural body mass at 4-6% is 81 kg (178.2 lbs.). When body fat is taken into account, this equates to a lean body mass of between 76.1 kg (167.5 lbs.) and 77.8 kg (171 lbs.).

Again, since my current lean body mass is roughly 70.4 kg (155 lbs.), this put me at 90-93% of my genetic potential based on this equation, which is remarkably similar to that of the previous equation.

Taken together, these predictions sound about right, as I’ve been weight training for about eight years; the last three or four of which have specifically been aimed at muscular development. Given the extremely slow rate of muscle gain following years of dedicated weight training, I don’t expect to be gaining the predicted 5-7 kg (12-16 lbs.) anytime soon. Assuming I could gain on average 3-4 lbs. per year (if I’m very lucky!) this would take me at least another four to five years or so to reach my apparent genetic limit (unless I turn to steroids, then it would be within a year).

Are there exceptions?

Like any predictive measure, there are always outliers. However, these genetic freaks are few and far between and were purposefully left out of Casey’s model since their drug-free status cannot be verified. Furthermore, as stated in part one, these equations were developed using data collected from elite drug-free bodybuilders (i.e. the people who have won the genetic lottery to begin with and have been training extremely hard and consistently for a decade or more). So, if it were possible to surpass these predictions, it would no doubt be a natural bodybuilder and it would hardly be by a meaningful degree. The average gym-goer going through the motions a few times per week can forget about reaching such stats, at least without drugs. That’s not to say these individuals cannot attain visually impressive physiques.

So, for all intents and purposes, these predictions cannot be surpassed. As such, any individual that can be verified to exceed such stats, and isn’t a pro natural bodybuilder with at least eight years of training behind them, is clearly using drugs (whether they admit to it or not). While I have nothing against people who take steroids, I dislike people who claim to be natural when they’re clearly not.

Aside from the dishonesties of some steroid users, some people are genuinely drug-free and “appear” to surpass such predictions. For example, people are notorious for severely underestimating their true body fat percentage. As such, these individuals may think they surpass the predictions (particularly Martin Berkhan’s due to the fixed body fat reference point), whereas in fact, the extra fat that they are not accounting for is assumed to be muscle. Therefore, if this individual actually reduced their body fat to the 4-6% body fat range, they would notice a substantial loss in body fat, which will no doubt put them within their predicted muscular potential.

I should mention that this might not be due to the person lying about their body fat measurement; rather, it is more often than not due to the inaccuracies of the various body composition techniques. For example, after measuring skinfold thickness (assuming the measurements are taken by a competent person), these skinfold measurements are entered into one or more of many equations available for predicting body fat percentage. Such equations are only as valid as the sample they originated from, so it is not uncommon to see body fat estimates for lean individuals deviate by as much as 5% or more, depending on which equation is used, despite using the same skinfold measurements.

So, using a fictional example, say that a person is 6” tall and weighs 87 kg (191 lbs.) and their chosen skinfold equation incorrectly puts them at 6%, this would equate to a lean body mass of 81.8 kg (180 lbs.), which surpasses their predicted natural potential. In reality, their true body fat percentage could easily be 10% due to the lack of validity of the chosen skinfold equation. 87 kg (191 lbs.) at 10% body fat would then equate to a lean body mass of 78.3 kg (172.3 lbs.), putting them within their predicted genetic potential.

Leigh Peele wrote an excellent article about this, which allows people to verify their body composition results via real-life examples of a range of body fat percentages. For example, a bodybuilder at contest condition should set the benchmark for minimum attainable body fat percentages (3-5%), which should make for a more accurate estimation of their own body fat percentage in spite of what the skinfold equation spits out. The picture to the right shows what a minimum attainable level of body fat actually looks like on a natural bodybuilder.

 Limitations of the formulae

These equations were developed using males, for males. As far as I’m aware no such predictions exist for women. However, if they did, they would be WAY below the values outlined here.

Martin Berkhan highlights a limitation to his formula in that it only “assumes average genetics” (which is also the case for Casey’s equation). There are true cases of non-responders to weight training meaning that the notion of a “hard gainer” is indeed correct. As the term hard gainer implies, these individuals have a more difficult time gaining muscle mass, despite appropriate training and nutrition. Because of this, these people may not ever come close to the limits of the predictions outlined in part 1.

This sparks the question, “if there are hard gainers, surely there are easy gainers?”. While there are genetically gifted individuals, in Martin Berkhan’s experience, “high-responders simply gain muscle mass faster than someone of average genetics; the cap for maximum muscular potential (height - 100) does not seem to be raised by much”.

How do I go about reaching this potential?

Now that the limits of natural muscular development are understood, I will briefly outline the steps someone should take in order to get there, or as close as possible.

Perhaps the most important factor in realising this potential is consistency. Despite all the ridiculous marketing claims, the only way to gain muscle quickly is through the use of drugs. It is possible for naturals to gain weight quickly with the use of weight gainers etc. but the majority of this mass will be fat. Any natural who has achieved such stats has been training consistently week in week out, month in month out, year after year, for at least a decade, or close to it. Given the diminishing rate of muscle growth over a training career, a year’s worth of hard work in the gym can bring about a 1-2 lb. gain in muscle tissue after five or so years of training, which can be disheartening even to the most dedicated trainees. Nutrition and training author, Lyle McDonald of bodyrecomposition.com has estimated the potential for muscle gain on a yearly basis in table 3 to give people realistic expectations of rates of muscle growth in order to set appropriate training goals.

Table 3. Potential rate of muscle gain per year

Years of proper training Potential rate of muscle gain per year Per month
1 9-11 kg (20-25 lbs.) 1 kg (2 lbs.)
2 4.5-5.5 kg (10-12 lbs.) 0.5 kg (1 lb.)
3 2.3-2.7 kg (5-6 lbs.) 0.25 kg (0.5 lb.)
4 0.9-1.2 kg (2-3 lbs.) Not worth calculating
5+ 0.45 kg (1 lb.) Not worth calculating

Speaking of training goals, a good way to plan for progress is to keep a training log. That way, you can objectively track your progress as opposed to just going in the gym and lifting based on how you feel that day. Following the FITT principle, this progression can be in the form of frequency (how many times per week), intensity (typically the load lifted), type (addition or rearrangement of exercises) and time (volume; set and rep schemes). The concept of tracking progress can also instil a degree of motivation, especially when you see your lifting numbers going up on a consistent basis.

Regardless of the other points above, you can never come close to your predicted muscular potential unless you have a solid training and nutrition regime in place.

Nutrition sets the potential for muscle growth. If adequate calories and protein are insufficient, you can forget about gaining muscle optimally. Calories should be set at just above maintenance for optimally gaining muscle, whereas protein should be a minimum of 2 g per kg of bodyweight, ideally more (e.g. 2.5–3 g/kg). In this article I discussed protein requirements in more depth.

In terms of training, the focus should be on gaining strength in the following lifts and/or their variations at least once per week (preferably in the 6-8 rep range, on average): deadlifts, squats, bench press, press, barbell row and chin-ups; muscle gains will follow. Some direct calf work wouldn’t hurt either. Isolation exercises such as bicep and wrist curls, made popular by drug-fuelled bodybuilders (and what most people seem to do in the gym!), aren’t necessary for the first one or two years of training; the focus should be on the outlined exercises which give the trainee the biggest reward for their time invested in weight training. Isolation exercises may be introduced after this period in order to bring up lagging body parts, but they shouldn’t interfere with progress in the main lifts; they should enhance it, if used correctly.

There is obviously much more to it than this (e.g. optimal set and rep schemes, training frequency, volume, periodisation etc), but this is a good start for beginner/intermediate trainees (and the vast majority of gym-goers) in order to develop good strength and muscle gains.

To conclude, I’ll reiterate that the point of this article is not to appear negative and state what someone will or will not achieve, rather, it aims to provide a realistic expectation of what actually is achievable without the use of drugs. Casey summarised his findings rather nicely, “The equations presented in this text accurately and precisely estimate the weights and muscular measurements of practically every elite-level drug-free bodybuilding champion of the past 61 years…. If the equations were not valid, for any theoretical reason, this simply would not be true. Considering bone structure size and muscle belly lengths they also apply to the average aspiring bodybuilder. It is not my intention to imply that no one will ever surpass the predictions of this text. It is, however, my intention to put what such an accomplishment would represent into proper context and likelihood”.