If you want to know what science says about predicting your genetic potential for gaining muscle and strength, then you want to read this interview with Menno Henselmans.

Key Takeaways

  1. Genetics dictate about 50% of your ability to gain muscle and strength.
  2. No matter how “bad” your genetics are for gaining muscle and strength, everyone can make significant progress with the right diet and training plan.
  3. You can’t predict what your body will look like once you’ve reached your genetic potential, so focus on getting as big and strong as possible and then get lean.

How much muscle can you gain naturally?

How fast can you expect results from your strength training plan?

What can you expect to look like after you’ve put in several years of hard training?

We’ve all asked ourselves these questions, and it’s remarkably hard to find straight answers.

Some people say that no matter what you do, there’s an absolute ceiling to how much muscle you can build, and it’s probably lower than you think.

Others say that’s nonsense—that with enough hard work, you can get as big and strong as you want.

The rising rate of steroid use doesn’t help matters either, because while some guys are so freakishly huge that there’s little question as to whether they’re “natty,” many drug users aren’t so easy to spot and lead people astray in their personal expectations.

To help get to the bottom of all of this, I interviewed bodybuilding coach, writer, and researcher Menno Henselmans of BayesianBodybuilding.com.

If you’ve been wondering about how your genetics influence things like the rate at which you can gain muscle and strength, how big and strong you can ultimately get, how your muscles look as they develop, and more, then you’re going to like this interview.

Here’s Menno breaking it all down …

(Rather listen to this interview instead? Click the play button below.)

Mike Matthews: One of the questions that I get most frequently is, “How much do genetics affect how quickly you can gain muscle and strength?”

And then the kinda follow-up question is usually, “Okay, so what are some realistic expectations for someone just getting into weightlifting in particular?”

I get that from a lot of guys who are new, because, you know, they’re on Instagram and they’re looking at all these different people, and they don’t know what’s drugs, what’s not drugs, and they don’t know what’s real, and what’s not real in terms of time frames and so forth. So I think that’s a good place to start.

Menno Henselmans: Starting with your first question. How big of a role is genetics in how much muscle you can gain? How strong you can get? It’s big.

Now, to quantify how much, researchers, for these kind of questions, they often express something as a hereditary coefficient, which is roughly interpreted as the percentage that your genetics affect your results.

Mike: Okay.

Menno: So, you can think of it as how much your genetics can predict, relative to other factors, like environmental factors. In this case, being your training program, your nutrition, your sleeping, all those things.

Mike: Sure.

Menno: And here, we see that there is a very, very significant influence. We can start with that. It’s so big, in fact, that in research at least, we have people who are deemed nonresponders because on any given training program, they don’t grow any muscle at all, or they don’t gain any strength.

I’m actually not really in favor of the term “nonresponder” because, in all my years of coaching experience, and as a coach you often get the hard gainers, and the people who have tried everything. I have a lot of people who have had 5 different coaches, and they’re like, “Okay, this is basically the last attempt I’m gonna make”.

What I’ve seen is that I’ve had 1 person that really probably couldn’t gain anymore muscle. He could lose fat, he could gain a six pack, he could build some strength at least, but in terms of muscle growth it was just, it was so little that it was already intermediate level, so definitely not –

Mike: Yeah, I was gonna say, cause you just said anymore, so I don’t –

Menno: Yeah. So I’m not really convinced of the presence of there actually being complete “nonresponders,” but at least we see them in research, and that’s probably because they didn’t respond to that given program.

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Mike: Over, y’know, the time period, and also how are the results measured? I mean, they’re …

Menno: Yeah. Exactly, so. And we know that different people react better to different programs. We can get into that as well.

Mike: Yeah, that’s a good point. We should talk about that.

Menno: Yeah. We have these people that, at least through that given program they don’t respond, and other people we see rates of increase in those kind of studies of I think 2, 3 fold.

We have people gaining 250% strength, which is huge, so they’re more than doubling their strength level. Other people, they don’t really gain anything. We have this huge variance. That is a fact.

But if we look at the hereditary coefficient, we see that it’s around 50%, and I think for obesity, the most recent estimates are actually closer to 40%, so your genes would explain 40% of who gets obese and who doesn’t.

That’s actually less, 40% of this, than what we see in most other research, because for people that don’t know, I actually came from a background of Economic Psychology and Statistics, and I made the career switch from Business Consulting to working as an online coach, and so I’m familiar with a lot of other research areas as well.

I know that, in most other areas, 50% is actually the normal. It’s actually just seen as a normal average. Which is kind of, almost, seems too coincidental, right? You have environmental factors and you have genetic factors, and it seems that –

Mike: Yeah, just there’s a balance there.

Menno: Yeah, it’s about one to one. It’s about 50/50. It seems too coincidental, but it’s true for a ton of things, including, for example, your personality.

In that line, you can get screwed over by your genetics more in terms of strength training, than you can get through it for your intelligence, or your personality, or your height. Any other such factor.

In that line, you know, it’s not that bad. But we do just see these huge variants, and I think that people maybe a bit, thinking about it too gloomy, because they look at the extreme outliers, right?

They hear about these nonresponders, and then they think of stories like, the most famous I think that has actually been verified, is Andy Bolton. I often use him as an example in my PT course, as an example of the most extreme outlier, cause I think he squatted, I think it was 500 pounds.

The first session, he was in the gym or something like the first session, and with that 600 pound deadlift soon to follow. That’s just –

Mike: I know one person that is, I mean, he’s not that much of a freak, but his first deadlift ever was, like, 405, and now a year and a half later he’s pulling 600+. What is that?

Menno: That’s good.

Mike: You would look at him, he just looks like a normal guy. Now he looks a bit more muscular, but he’s not some … he’s not the short, super stocky dude.

He’s actually like 6’4″, and looks pretty muscular, fairly muscular, but you would never guess. I told him he should go into gyms and just make bets, he can just make money that way.

Menno: Yeah. That’s actually another interesting aspect of genetics, is how much can you predict based on what you see, right? Strength, we know that the variance is a lot bigger.

It’s actually really straightforward as to why this is, why we see more variance for strength than for muscle growth, and that is because everything that affects muscle growth, basically also affects your strength, because given any sort of neural level, I often use the analogy of your brain being the driver and your muscles being the race car.

So, given any level of neural development, a bigger muscle means more total force production. Specifically, a scientist would say a larger cross-sectional area, always being equal, always increases total potential force output of that muscle tissue.

Therefore, we see that we have this variance in muscle growth, how much muscle you can gain, but the variance in strength is even bigger. Because not only do we have these morphological factors, as they’re called, such as muscle size that affect your strength. We also have other, morphological factors like biomechanical factors.

For example, the angle at which a muscle inserts on the tendon. Even a very minor difference in this angle … or pennation angle of the muscle, for example, which you cannot see at all, visually, looking at degrees, this being internal … your body can make a huge difference, because we’re talking about these tiny angles, that you can have a slight difference in angle, that basically doubles the leverage the muscle has on a particular bone or joint.

That basically means that it can also double the force output, so you can have these two people, that have the exact same amount of muscle mass, and they also have the exact same amount of neuro development, but one of them simply has the insertion points of the muscles and the tendons on bones that make that person a lot more suitable for heavy lifting.

They are actually producing the same amount of internal force, and the muscles do the same kind of work, but it can be a twofold difference in external force output. Meaning, they can lift twice as much weight, while they only have to do half the work.

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menno henselmans muscle growth genetics

Mike: Right, and I guess a simple analogy could be like the lever and fulcrum type of … you know, depending on how it’s set up, the amount of force that can goes in can be disproportionately larger in terms of what goes out.

Menno: Yeah, that’s exactly right. So you can also have with cable pulleys in the gym, for example. A lot of my clients are surprised, they have at a certain exercise. They’re using a certain cable pulley, and then the next session they use a different cable pulley, but couldn’t lift nearly as much weight.

But, if you’re just changing the amount of pulleys that can double the resistance. That’s also why, machine work, a lot of people ask, “What is an impressive lat press?” And my answer is, “There’s no such thing,” because the different lat press machines can have such incredibly different leverage and –

Mike: That’s very true.

Menno: – rates, that you know, one machine you can barely press more than you can squat, and on a different machine it’s just, several fold. You can just put obscene amounts of weight on there.

Then you have these guys looking around, and they have someone else step on the lat press, and then they do the quarter lat presses, and they’re like, “Oh yeah, I lat press a thousand pounds,” and they can barely squat three plates at that.

Mike: Right.

Menno: It’s biomechanics, it’s not really strength.

The other fact that we have that also explains how strong you are is the speed. You can group that together as neural factors.

It’s like, how advanced the driver is? How well the driver can control the car? Meaning, how well can the brain control your muscles? There are also more peripheral factors like, your neurons, how fast can the signal transduce through your neurons and reach your muscles, but it’s largely analogous to the driver and the car.

Or you can think of it as hardware and software. How well can the software control the hardware? If you have, for the computer people, I’m not even sure if this analogy is right because I’m not that good with computers.

But I know that certain pieces of hardware, you can overprop them, depending on how well the software functions. So you can have the same kind of graphics card, like physical material, but if you have better software it can make more use of that same card.

Mike: Right. Yeah, that makes a good analogy.

Menno: With these 3 factors you basically have the variance in strength, and it includes muscle, so much bigger variance there.

Mike: Yeah, so just to summarize then.

You’re gonna have people who are just mechanically set up to be stronger, and you’re gonna have people whose muscles can contract more forcefully, where, like you were saying, the software, it just better uses what’s available.

Then, what about in terms of just potential for high speed, potential for size? I think you had mentioned a little about that earlier, but that’s really where I get asked. I mean, this is mainly guys asking, because they’re concerned that they’re never gonna be able to look like, you know, so and so. I mean, you had touched on it with nonresponders versus hyper responders, I guess you could say.

What are some realistic, if you looked at it in terms of pounds, and let’s say the first … if it plays out over, let’s say 5 years … so, for muscle growth, for guys and then also girls. I mean, I don’t get asked very frequently by girls, but there are women out there who are concerned with it.

Based on your experience and research, what do you say are some realistic expectations?

Assuming that they’re following at least a well-designed training program, and they know what they’re doing with their nutrition, and they’re not under eating, or eating too little protein, or doing anything obviously wrong.

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Menno: Let me pull up the exact figures I have of this from my PT course.

First thing, you should generally think of this as percentage of body weight increased, because if you think of it as pounds it can be useful, you have a pretty common rule that novices, like novice men, most men gain about 2 pounds a month, purely in tissue, I’m talking about, when they start training. So, novices.

Beyond that, it gets very tricky because you have one guy that weighs 200 pounds, another guy that weighs 60 pounds, and obviously they’re gonna have a very big difference in how many pounds of muscle they can add.

I generally like to express everything in terms of percentage increase in body weight gain. The nice thing about that is then, you also take the gender difference into account.

Because, contrary to popular belief, men and women actually have the same muscular potential. Given the same starting muscle mass, say baseline muscle mass, they can actually grow the same amount.

I have a very adept article on my website about that, “The natural muscular potential of women,” I think it’s called? And you can check that out –

Mike: I read that article, I liked it.

Menno: Yeah, you can check that for all the references, or listeners can. But yeah, there’s a lot of research from protein synthesis, from training studies that actually looked at muscle growth, and also from elite athletes cross-sectionally. It all points in the same direction, that muscular potential is actually the same.

Although, they do respond differently to different training programs. Men and women should not generally train exactly the same, but that’s a different topic. To the actual figures.

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menno henselmans genetics women

Mike: And just to not leave people in the mystery, so then what’s the big difference there? It’s where women start, right? So the big difference between men and women in terms of muscle, is that women start with so much less, right? The average woman –

Menno: Yeah, exactly. They just weigh a lot less, and they have higher body fat percentage naturally, because boobs, and well, other factors as well.

Mike: Hips and, you know, gotta rear children and stuff …

Menno: It’s all these factors. They start with a lot lower baseline level of fat free mass, but given the same starting point of fat free mass in terms of pounds or kilograms, the muscle potential is the same.

Given the same starting weights, the potential is also very similar. If you have 170 lb male, and 170 lb woman, there’s very little difference in what they’re going to be able to accomplish in terms of strength and muscle growth. In power men perform –

Mike: Interesting.

Menno: – better, which is why, in most sports, men do dominate, but it’s also cultural differences there, so, anyway –

Yeah. So, the actual rates that I think are realistic based on the research, my experience that I have in my PT course.

Novice individuals can expect to gain about 1% of body weight per week. That’s basically cut in half as soon as you’re at the intermediate level. Intermediate here means seriously trained.

Mike: 1% per week? Not, per month.

Menno: Yeah, per week. That’s like –

Mike: Well that’d be, somebody at 200 pounds, then you’re talking about 2 pounds? Cause then that scales down in time, then, right?

Menno: Yeah, it scales down very rapidly.

Mike: But like, okay good, I just wanted to make sure, because guys are gonna be like, “What? I can gain -“

Menno: For my first year I can gain, if I’m starting at 150 pounds, I can gain, whatever –

Mike: 50 pounds in the first year?

Menno: That’s the other thing. Remind me in a second what the time frame we attached was.

Mike: Okay, sure.

Menno: But yeah, for a novice, which basically means starting with untrained, right?

Mike: Right.

Menno: Completely unchecked.

Mike: Right.

Menno: At 1%. So yeah, that’s aggressive. That’s, I think, realistic but achievable for the average individual.

Mike: For how long do you see that playing out?

Menno: Not long. You’re talking about six pounds will show up, probably? At best? But yeah, I think your first year, you can see very significant progress.

I started at 65 kilos myself, and then I actually sort of intentionally dropped down to 60 kilos, and I was this really, really low weight cause I was already 6 ft at that point. Then, within a year I bulked up to about 80 kilos, still with abs.

Mike: Wow.

Menno: I then spent about 10 more years, basically recomping, to get to that same weight, but in contest shape. And then, now in the last 5 years or so, I managed to get to 6 more kilos.

So, yeah, it scales down really fast, but the thing is how many people start off on an optimized program? Almost nobody does. Everyone, they have to trial and error, they have to figure things out.

Even among my clients, because it’s still rare that you have a novice start off training completely optimally, doing everything right, because either the adherence just isn’t there yet, or they have other goals, or they’re only willing to train twice a week. Even if they have the coaching, often it’s still not gonna be actually maxing out in their potential.

But yeah, everything being right? 1% per week of body weight. Healthy gains, like lean tissue. Well, maybe a little fat, but not much.

Mike: And would you say that that’s right down, that’s for a person with average genetics? Or would you say that’s for a person that responds better than average? Or –

Menno: Just an average person.

Mike: Okay.

Menno: This basically cut in half as soon as someone reaches the intermediate stage. You’d be at 0.5%, and then it’s cut in half again once you reach the advanced stage, and you’re looking at 0.25% per week of body weight.

It’s very little, that’s what a lot of people, they don’t recognize on the scale as they’re meticulously tracking everything.

Mike: Yup, yup. And then also, I mean, your diet has to be pretty consistent in terms of even lack of nutrients there, because if your carbs are going up and down it’s hard to see what’s really happening with your weight.

Menno: Yeah. If you drink alcohol, you wake up, it has diuretic effects or you’re dehydrated. If you have a bowel movement one day, but not the other day.

These things can have variations in body weight that are a lot larger than what you will gain on a weekly basis as an advanced individual.

Mike: Right, and that’s probably why. You’re probably looking at your average weight over time in that scenario, right?

Menno: Yeah. And as a reference, what I did, which was now in a year or two years, everything I could for a year, and I consider myself an elite level trainee. Not because I’m world class in absolute terms, but in terms of my genetic potential I think I’m pretty much there, fortunately.

I did everything in my power to gain as much muscle as possible, which I usually do, but that year made sure I was meticulous with everything, and I made very sure to record for two week straight in the most stable conditions I could achieve.

I set food intake, set water intake, everything. Recorded caliper measurements, circumferences. I basically concluded from that, that I gained 1lb of lean tissue.

I was really happy with that, because I expected zero, so I was still likely making progress, which was very good news to me, because that’s basically what I wanted to find out.

But yeah, when you’re at the elite level as a natural trainee, you’re looking at yearly progress. You’re looking at very sharply diminishing returns to your training time.

That’s what I was referring to earlier, like the time frames we attached to this. Now, I’m going to make a very controversial statement, but I think, based on what I’ve seen in terms of people that train optimally, and also some historical data, of individuals like Steve Reeves, and people that trained really hard in the classic era.

I think you can come very close to approximating your genetic potential within 3 years of optimal progress.

Now, the distinction here being very crucial, that optimal progress is not total training time. You can easily, and I’ve done so myself, waste 3 years of training time without making any progress.

Mike: I probably wasted at least 3 or 4 years before I finally got my act together.

Menno: Exactly. It’s common, even. This is absolutely not total training time. I get these people like, “Oh, I’ve been training for 3 years, I’m there.” No, no, actually not.

Mike: You’ve been exercising for 3 years. There’s a difference there.

Menno: Yeah. I’m talking about 3 years of doing everything right, and making the best progress you can make.

Theoretically, if we have a certain individual, say a completely robotic individual, then I would be confident that a very good coach could make that person achieve his or her genetic potential or come very close to it within 3 years.

Probably 80% of that, something like that. 80% is actually a figure that comes from a lot of data. The 80-20 rule, it’s based on empirical data, because most functions in life have a power law if they’re not normally distributed.

So 80% is probably a good estimate for the first year, something like that. But again, stressing that this is the period of time doing everything right.

I think, people in general in the industry, they underestimate what you can achieve, but they overestimate how long it takes.

It doesn’t require, like you see people, like, “It will take 20 years to reach your genetic potential.” I don’t think so, I think the body simply does not have that kind of adaptation, because evolutionarily speaking, it makes no sense to have an adaptive system that is either capable of or requires 20 years of training to reach its full potential.

What kind of evolutionary stimulus are we talking about that requires 20 years of doing something before your body has mastered it? That just doesn’t occur in nature. I think most of things you do, looking at more years before you’re mastering a skill. Yeah, I think that about sums it up.

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Mike: And then just on that point, that’s a good segue into the next question because that’s something I’m also asked frequently about is how to predict … and again, this is usually guys that are new to training … and they wanna know is it even possible for you to look like so and so.

What are your thoughts on … I mean, it’s based on a bit of research … it’s based on information out there, correlating basically the ceiling of your FFMI, what that can be naturally?

Then at what point is it clearly drugs? At what point is it in the gray? Do you think there’s any semi-accurate way for somebody new to weightlifting to go “realistically, I could get to somewhere in this range?”

Or is this something that they, you know, they just have to … it’s gonna take years, and then they can make a prediction?

Menno: Yeah, let me pull this up, because in my PT course I have reference data on the FFMI. Yeah, it’s here.

So the FFMI for people who don’t know is the “fat-free mass index.” It’s like BMI, which is “body mass index.” But BMI kinda sucks, for instructional needs, because it’s just a relation between weight and height. It doesn’t say anything about your fat percentage.

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Mike: It’s more for population analysis, right?

Menno: Yeah, exactly. It’s for people who don’t lift, because then you can assume a certain level of fat free mass based on their gender and height, because if someone’s not training, and their protein intake is somewhat normal, you can be sure that they have a certain level of muscle –

Mike: Yeah, and age, right? Cause as they get older they’re gonna –

Menno: Yeah, yeah. Exactly. Although, actually, it’s mostly disuse and not age itself, but that’s another topic. So, we have body mass index, kind of useless. Which is why we have the fat free mass index, that researchers developed to look at how muscular you are, because it relates your fat free mass to your height, and it completely ignores fat mass.

It just says how much lean body mass, which is roughly a proxy for muscle mass, you’re carrying. Now, researchers have studied this and there’s a very infamous, or famous study that basically concluded that a fat free mass of 25 is as good as it gets for a natural trainee.

There are a lot of very serious problems with this study. Consequentially, the idea that a fat free mass index of 25 is about as good as it gets. For one –

Mike: And just to put it in perspective, just so everybody knows. Do you know what your FFMI is? So if people wanna look at your physique and go, “So what is this? What does 25 look like?”

Like, I know I’m right around 24, and so people that know that I would look like … you know, I’m much more muscular than the average person, type of guy, so 25 is pretty big. Do you know yours?

Menno: Actually, I’ll fill it in right here.

Mike: Just to give listeners a visual on what does that look like, you know?

Menno: My normalized fat free mass index is, or in my last condition, is actually only 23.6. That’s to show that 25 is big.

Mike: Yeah, you’re a big dude at 25.

Menno: Well, it depends. In person, it varies, but I think a lot of people, it goes both ways. Some people are like, “Oh, you look bigger in the pictures,” and I think I do because pictures are always great, you’re flexing and you’re pumped, and –

Mike: And the leaner you are, you get that effect where you look bigger. Your weight almost doesn’t make sense for how big you look.

Menno: Yeah, in general the leaner you are, the better you look in a photo. The better you look in a t-shirt, so –

Mike: Did you get really lean for shoots and stuff, did you get, if you wear a long sleeve shirt, where people are like, “What happened? Do you even go to the gym anymore?”

Menno: Yeah, well there are 2 redeeming factors there, because for one, my forearms get crazily vascular, so if there is some sleeve not covering my forearms there’s no mistake. Just because my forearms are so vascular.

Second thing is, why a lot of people actually think I look bigger in person, I think it’s the difference between people that have seen a lot of big dudes and have seen me in person, I’m not that impressive, I make a bigger impression in the photos.

But, on the other hand, you have people that haven’t really seen a lot of truly big guys, and then when they see me they’re like, “Oh shit, 6’1″, 200 pounds is actually a big dude.”

My shoulders are genetically my best body part, so I have quite wide shoulders and, combined with height, especially here in Asia and when I was training in India, people were like, “Holy crap.”

Mike: Yeah, you’re like Godzilla over there.

Menno: Yeah, exactly, cause I’m like literally a full head taller and very broad shouldered.

Mike: That’s funny.

Menno: Yeah. It all depends on who you ask.

Mike: Sure.

Menno: But anyway, the fat free mass index, you have that study that concludes that 25 is about as good as it gets. But all that study really did is, they got together a bunch of muscular guys, strong guys.

They had some truly high level people like international body builders, bar lifters that set records. And they basically concluded that in that sample 25 was as good as it got.

Thing is, it was just getting a bunch of people together. There’s no way to conclude from that, that just because in this sample it didn’t occur, that it’s not possible.

Actually, that same study concluded that it is possible, because they analyze the records of pre-steroid, legitimately, almost could not have been steroids physiques like Steve Reeves, in the 30’s, early 40’s, where steroids simply were not in circulation yet, or you were like looking at serious conspiracy theory level stuff to think that these people were on steroids and they concluded that –

Mike: And you think that with Reeves? Cause I mean, testosterone was pretty widely available at the time.

Menno: Reeves was actually sort of in the transition period where, I think Reeves was natural, but there are some … I think there was a letter of someone saying that he wasn’t, and –

Mike: Yeah, I remember reading about it and I was like “Huh, interesting.”

Menno: Yeah, so it was like in the gray.

Mike: The gray, yeah.

Menno: It was way before that as well. Let me pull that up as well, the reference … 28.0 is the largest natural trainee ever recorded.

Mike: That’s big.

Menno: Yeah, that’s 3 points above 25. I’ll give the other reference data as well here. So, normalized fat free mass index, 28 is the largest natural trainee ever scientifically documented.

Here’s the other thing: we have a case study of another world class, natural pro bodybuilder, that was followed with blood work for a very long time period during his whole contest prep, and his fat free mass index was 25.4.

There, again, goes the idea it not being possible to go above that level. It’s just rare. That 25 level is where the average person probably, it’s a fairly decent sample, that they’re not gonna get above 25 while they’re six pack lean.

Distinction there, because sumo wrestlers are actually among the largest, most muscular individuals on the planet, if you look at cross-sectional data. A lot of these guys, they don’t do strength training, and basically sit around and eat all day while they do a lot of … yeah.

They’re really, really fat, and it’s just a general fact that the more fat you have, the more muscle you can carry. Which is why they are incredibly muscular underneath the huge amount of fat.

We also see this in many powerlifters, bodybuilders, and it’s the infamous story of people saying, “Oh, my fat free mass index is this, and I have these standards, and my biceps are this amount of inches. Oh, these guys are all really small.” Let’s talk again when you’re in contest shape –

Mike: Yeah, go, let’s start at 10% body fat, let’s start there and see how things are looking.

Menno: This being a true 10%, a full six pack abs level. No, not 10%, of guys that they think “I’m close to 10%” because they almost have abs.

Mike: In the right lighting where, you know, they’re twisting …

Menno: Exactly. Like, super selfie lighting, Myspace angle, it’s a –

Mike: Yeah, no. Like abs, no flexing, type … you know …

Menno: Yeah. In reality most muscular trainees have serious abdominal definition at 15% body fat, so for a muscular individual, if you do not have any abs … although harsh, a bodybuilding framed reference would be “You are fat as F*ck.” For bodybuilding terms, not having any abs at all, there’s no reason at all for a natural bodybuilder to ever go to that high of a body fat percentage.

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menno henselmans body fat percentage

Mike: I agree.

Menno: But again, this being body fat, bodybuilding standards, right?

Mike: Sure, sure.

Menno: So, I think –

Mike: That’s a good point on that FFMI data. That’s also, I’ve written an article about it and kind of presented in that. This is interesting information. I think it is valuable, and it gives us insight, but it doesn’t mean it’s a hard and fast rule. Would you agree with that?

Menno: Absolutely. What I did with the calculator, in my PT course, I express it as a … actually, this is not yet in the PT course … but, we’re building a calculator, at least, for cybernetic fitness, and it expresses the probability that this can be attained naturally.

So, you could frame it like that, and then 25 comes about, the level that there is a significant chance that this individual is on steroids, but it’s very possible to obtain naturally.

As always, people want the magic answer. It’s like, when you’ve done a test at college, and people ask, “How did you do?” They’re not asking how you did, they’re asking how they did. Cause they will compare themselves to you.

That’s the same, when people ask, “Is that guy natural?” They really don’t care if that guy’s natural, they want to know, “Can I look like that?”

It’s a nonsensical question because you look different, you have different genetics, you’ll never know if that person was natural or not. It doesn’t change anything.

All you can do is maximize your own muscular potential, be the best you can be, as the cliché goes. It’s a cliché because it’s absolutely true.

Mike: It’s very fucked up when they moved away from that. That was a better slogan than … they changed it like, “Army strong” or something? Be all you can be is so much better.

Menno: Yeah, exactly. I mean yeah, that’s all you can do, so, you could look at all those guys and it doesn’t have any practical information for your life.

Mike: I agree, and I mean to that point, it’s even where a lot of people, I mean drugs are very prevalent in not just bodybuilding, but in weightlifting in general. People would be surprised if they knew what people, and I said this many times, in the gym are on drugs and are not on drugs.

Cause just cause someone looks, by bodybuilding standards, pretty bad. They’re overweight, and they don’t really have much in the way of proportionate muscle development. A lot of people that are on drugs, that’s what that is. That’s what they’ve gotten out of it.

Then, on the other hand, you have people who look quite good, that stay lean, that have done a good job building their body in an intelligent way. They look great, and they’re not on drugs.

There are obvious cases when people are scrolling around Instagram, yeah. There are guys that there’s no question, absolutely no question. Their shoulders are bigger than their heads, and their FFMI would be whatever, 30+.

Of course, drugs. But, to that point, it’s hard to really know cause just cause someone looks good doesn’t mean drugs. Just cause someone looks bad, but they’re just kinda big and strong, that could absolutely be drugs.

Menno: Yeah, exactly. The other reference point I had here is really interesting. In that study, they also looked at steroid users to compare them with the natural trainees, and the average steroid user had a fat free mass of 24.8. Actually, below the supposed natural limit.

Let me see if I can pull this up somewhere as well, I have also calculated the fat free muscle index of individuals that are clearly not natural.

Okay, yeah. I don’t know their fat free mass, and this is here, at least the percentage is that, if you do the math on the probability, the percentage that they are, in fact natural, you get guys like Ronny Coleman, Jay Cutler, it’s 0%.

It’s just, there’s no rounding, statistically there is just no chance in hell you’re gonna look like that naturally. Which aligns with common sense, right?

Mike: Right. Just at that point, have you seen a few pictures of Ronny Coleman? Cause he said himself, it was some interview or something, that he started doing steroids at 23, I think he said. Yeah, actually, I’ll find it after this.

I’ve written about it, and I even linked to where he himself was talking about it. If you see pictures … have you seen pictures of him, even by his … I don’t know why he’d be lying then, I mean he was open about it saying, “Yeah, this is when I started doing it.”

And you see pictures of him at around right in before he got on drugs, and to this point I guarantee you his FFMI was quite high. He was fucking huge. Like, impressive, I mean, bigger than … he could have been one of these guys on Instagram with a million plus followers, even before drugs.

Menno: Yeah, but I actually, I’m not sure if Ronny Coleman’s history, what age he attained what, but I had it on good account that he attained his pro cart before he started drugs. So I’m not sure if that matched up with –

Mike: I think, yeah, again when we get off I’ll find it, I’ll email it to you, that maybe, it was like over a year ago or something when I came across it, where he was talking about, I believe yes it’s true, I believe that was the timeline.

Because he got introduced to it by another professional bodybuilder, who was like, “Dude, you need to try this shit, because look at you, you’re ridiculous,” you know what I mean? And he was like “okay.”

Menno: Yeah. I absolutely believe that. I’ve heard about Ronny Coleman too, and some other guys. They’re just already obscenely big before they started using drugs.

That makes sense because, at the top, elite level, those are visuals you expect to find, right? They have it all. They have the genetics, and the drugs, and the dedication.

Mike: Yup. And it’s like that with any sport. You have the best football players, or even anyone who makes it into the NFL, was a genetic freak their entire life. They were better, they were the best.

They stepped on the field at, whatever, 6 years old and were just better than anybody, and that was basically the story of their life until they made it to the NFL.

Menno: Yeah.

That’s actually an interesting thing about the relation between genetic potential and dedication. In my experience it’s strongly negative, being that the most talented individuals often do not have the dedication that, especially intermediate level trainees have.

In my experience, I think the optimal, about intermediate level, or even it’s just completely negative. The more of a hardgainer you are, the more you’re willing to do.

In the Netherlands, for example, we have this gymnast Yuri van Gelder as a great example. Thought about posting that before the Olympics, because there was this scandal.

I’m not really sure of the particulars, but on the day before his competition, I think, he was partying, using cocaine. He had a history of cocaine use as well. You’re talking about someone performing in the Olympics, and they cannot muster the dedication not to go drinking and using drugs the day before the event.

If you compare that to amateur level bodybuilders that I’m coaching, if you give that dedication to Yuri Gelder, we’d have –

Mike: World domination.

Menno: Yeah. We would have a specimen.

Mike: Yeah. There’s a friend of mine, he ran track in high school, and he was one of the fastest kids in Florida. He really didn’t take it very seriously, but before a run he would just go to McDonalds and just eat a couple hamburgers, and show up and not really even warm up.

And just run really fucking fast, faster than everybody, and never … he just didn’t pay attention to anything. It was just something he did.

Talk about genetics, his dad was briefly in the NFL as a running back, so I mean he just had it, and he was just like, “Yeah, whatever.” He didn’t care, so he didn’t go anywhere with it, but if he would have I’m sure he could have really gone far.

Menno: Yeah, that’s the thing. If you just have it, you don’t appreciate it. If you have to work for it, you appreciate it.

Mike: 100%. Same thing with money. Kids that come from rich families, if they just inherit money or have just always been around money, it doesn’t mean anything. It’s just “who cares?” It’s … you know, anyways.

So, great. I think that’s a good encapsulation of FFMI, and I think, you know, you’re mentioning this PT course, which when we get to the end you can tell everybody where they can find this information.

Where they can find your stuff, cause I know people are gonna be wondering now, “Where’s this calculator? I wanna see it!” I think it’s, though, good for just people to know, if you go look at you can use Menno’s calculator. If it’s available, obviously, it’s part of a course.

But also, if you just look at FFMI calculators in general you can get an idea of, I think it’s fair that, I would say … I don’t know if you agree with this, Menno, but … 25 to 28 is probably the realistic upper limit for most people that are getting into weightlifting.

Menno: Yeah. Again, I’m gonna give some more figures here cause I have them pulled up anyway. Arnold Schwarzenegger would still be 0%. Just there’s no way.

Mike: Just give his numbers real quick, so people know, like he was what, 6’1″ is his height? 6’2″?

Menno: Yeah, he was about my height, I think, so 6’1″.

Mike: And it was he was on the stage?

Menno: No, he was, I think he was like 100 kilos stage shape.

Mike: Right, about, I think it was about 230, 235 pounds maybe?

Menno: Yeah, so way beyond natural potential.

Mike: And lean, but not necessarily as lean as what we’ve seen in more recent decades.

Menno: It’s not modern bodybuilding lean, but for any standard lean.

Mike: Very lean.

Menno: And then we have some … I also did these calculations. Martin Berkhan, and Alberto Nuñez. Both great physiques, we’d be looking at 86% probability that they’re natural. Now, without making any claims about whether they’re natural or not, for a lot of people these are physiques that can be obtained naturally.

martin berkhan

alberto nunez

Nathalia Melo? 98% probability of being naturally achievable. Not too surprising, cause she doesn’t compete in bodybuilding or anything. Frank Zane and Zyzz, you’re looking at the range of 21% probability of being natural.

frank zane


Mike: Interesting, now that makes sense with Zane, but what was Zyzz’s numbers? What information are you putting in there? I’m curious.

Menno: I’m not sure, I have this percentage output. But yeah, Zyzz fluctuated a lot. I probably had Zyzz’s top numbers, so that’s also not –

Mike: Is that possible? You know, cause he was very open in his drug use. I feel like his physique earlier on when he was a bit smaller, but he was very lean, that look is … I think it’s obtainable.

It’s gonna take quite a bit of time to gain enough muscle, and obviously you’re not gonna be able stay that lean all year round naturally, or at least not without feeling like shit. But I would think that someone could naturally achieve that look and maintain it for a little bit, and if they wanna do pictures and whatever.

I don’t have, I think, Zyzz’s body, I mean his waist was smaller, and I think aesthetically he beats me in several ways. But when I’m at my leanest, and I’ve gotten to where I would be comparable at least in terms of size and leanness, I just don’t look as good as he did at his leanest cause his body is just better built for it.

Menno: Yeah, exactly. He had these insane shoulder trap and chest insertion points that just make his muscles look so much fuller than mine as well, whatever look.

Mike: And then that small waist, then, you know.

Menno: Exactly. The last figure I have is Marc Fitt. But, he’s like 92% achievable match really. He’s just really lean, mostly. His level of muscularity is very respectable, but not something you would accuse someone of steroid usage for.

marc fitt

Mike: Right. Awesome, so I think that’s great. To just point out, you’re just talking about achievable naturally, so people that are listening, it’s not that he’s saying these people are natural, aren’t natural, whatever.

It’s just, that’s a good reference point of going, “Is it possible?” Yes, there’s a very good chance it’s possible. In the case of Frank Zane, nah, not so much.

Menno: Yup, exactly. There might be the odd individual that can actually look like Zane naturally, but it’s the odd individual.

Mike: Yeah, statistically speaking, unfortunately, anyone listening is probably not that person.

Menno: Yeah, exactly. And that’s the other thing, even if you attained that fat free mass index, you will not look exactly like that person because you have different insertion points, different muscle lengths.

The genetically best individuals often have very full muscle bellies, which creates that just completely convex, concave look that many humans find pleasing to the eye, find aesthetic.

Where, if you don’t have these empty spaces like some individuals have, they have short muscles, so if they get really large muscle it looks like unnatural, like this bulge they have, and it doesn’t flow as well as other individuals

Well so, for example, your abdominal structure, some people have this crazy, textbook like, six pack ab. Other people have an eight pack, and other people they don’t have separation at all in certain pieces of it, or they have this huge gap in between.

Mike: Or like me, I have staggered abs, and it’s kind of like a four, six, something in between. You know, unfortunately, that’s just the way I came.

Which is, this is a good segue into, I think this is the point that I ask about a lot, is this point of so what do genetics, how much do they determine how your muscles are going to work? I guess there’s 2 parts to that.

Like, how big can individual muscles get? Obviously, with guys it’s a lot of questions about chest and biceps, and occasionally calves. Girls don’t usually ask about how big certain muscles can get, but these days it’s kind of about butt I guess more than anything else. I think this is a good Segway into that.

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Menno: It’s actually hard to predict. You can predict it a bit, because you cannot change your insertion points, the length of, and also, at least not visually you can’t actually change the muscle length, but it doesn’t make a lot of visual difference because it’s internal. It’s muscle-vesical length.

But a muscle is actually going to change shape when you train it. It’s inevitable and you can change it to some extent. Like, for example, the traps being an obvious part, you can emphasize the upper or lower traps.

To a lesser extent, you also have different halves of the hamstrings, for example. And lesser extent, still, you have the different heads of, the two heads of the biceps you can emphasize to get one bigger, so you have bigger peaks, or you get the other bigger and it’s more flat and full.

But you cannot really predict that well how it’s going to change and, to a large extent, especially for a natural bodybuilder where the end goal is just maximum muscle growth in pretty much every muscle group.

To that extent, in a very long term perspective it’s not really up to your control, so your muscle size and shape are going to change, as a result of the growth. But it’s a limited change and one you cannot really do much about. You have a certain way that you look, and either relish it or go cry for the rest of your life.

Mike: Yep. I mean, that’s the long and short of it. Talking about biceps in particular, because that’s also then it’s a common thing is bicep’s peak. You know, you were saying you could influence it a little bit. What does that really look like, though?

And what does that look like in terms of training. So saying, someone’s listening and saying “I wish I had more bicep peak!” Is there anything they can do specifically?

Menno: You can a little. I’m gonna refer people to my muscle-specific approach free article there, cause it’s a bit dated article, but it still describes very well, especially this, what you can do to emphasize the different heads.

Mike: I’ll link it in the description and stuff too, so people can read it.

Menno: Alright, that’s good. And I think you asked one more question about genetics that I missed.

Mike: Just, the last couple points were the size of big, how much does genetics play a role in individual muscle groups? So, just as how individuals can be hyper responsive to weightlifting, is it also true that certain muscle groups can be hyper responsive?

Because, you know, people seem to have what is generally referred to as a “genetic strength.” That muscle group that, for some reason, just exploded and then other muscle groups … like for me, my experience has been my chest and my biceps have always just been high responders.

I’ve actually toned down the volume because I felt like they were getting too big … it forced me to, like, my shoulders always seemed to be just very stubborn, so the bigger my chest and biceps got, the more my shoulders looked bad. But my calves, for example, have been a never ending source of frustration.

Menno: Alright. I hereby dub that the Schwarzenegger genotype. Big biceps and chest –

Mike: And no calves.

Menno: Yeah, yeah. Well, he still had some calves, but yeah. Proportionally –

Mike: Yeah, no. I’m talking about myself here. Although I have something now, I mean I work for it, it’s just slow.

Menno: Yeah, same here.

The nice thing is that, based on the very limited research we have, we know that different muscle groups can have exceedingly different genetic potential.

Again, based on the very limited research that we have, I’m not really convinced of this, but at least in animals it’s suggested that there is in fact almost no relation between different muscle groups and their genetic potential.

Now, I’m pretty sure that there are certain genetic factors, muscles that we know of, certain genes that you have, certain systemic factors like how much testosterone you have being very common, although actually overrated one. These determine muscular potential for your whole body.

But, in principal, some core components such as how many satellite cells you have, how much myonuclear interactions you have … It’s very internal components of the muscle tissue itself that you cannot see, and that vary in each different muscle group.

They are very, very influential for how much muscle can be built, and they can vary a lot in different regions of your body. You commonly see individuals that have strong points and weak points.

For some people it’s quite pronounced, other peoples are more like in between everywhere. You know, what you don’t really see, and this is actually a good example of that, where I say I think this is limited research that we have.

Some people take it to extreme, and then they say, “Well, there’s no relation, because that’s what the research says.” But, how often do you see an individual that has truly really impressive upper body or pecks and just no biceps, for example.

It doesn’t happen. There is a correlation there, it’s just it’s obvious. But yeah, you definitely have strong points and weak points.

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Mike: Yeah, and then there’s also muscle fiber types that can come into play too, right? Just in my … it was really just kind of curious on calves in particular, I came across some research that just indicated that some people’s calves are high in fast twitch, and some people’s calves are higher in slow twitch, and that alone can explain a bit of why some people have good calves and rarely ever, if ever train them.

And then other people like me will train them quite frequently with higher rep ranges, lower rep ranges, really work at it and get not very much out of it.

Menno: Yeah. That’s true. The thing with the calves actually that’s, I wrote a specific article on that as well, “3 Reasons why your calves aren’t growing.”

The thing with calves is that, actually, the genetic potential doesn’t appear to be lower, and what you see in almost all elite of all competitors is that there is a nearly one, to one, to one ratio between the neck, the calves, and the upper arms in terms of certain appearance.

But the calves do have the potential to suffer or shine greatly depending on the attachment point of, especially the gastrocnemius, and the length of the tibia.

What you probably have, and what I have too, is that you have quite long lower legs, and the muscle is attached quite high up on the bone base.

Mike: Yeah, so it has to stretch a longer distance.

Menno: Yeah, and it’s just that one part. If you flex it, you get this nice bulge, but if you’re just standing it doesn’t appear very impressive because you have this long lower leg, and it’s stretched over a significant part. Whereas other people, the calves just sort of flare out more.

It’s like an exaggerated version of quad sweep. Some people have a lot more of it than others. I also have very little quad sweep, just like Arnold Schwarzenegger actually, a very similar structure, not the size unfortunately of the quad of Arnold Schwarzenegger. Whereas other people, they flare out way to the sides.

I’d say with the calves, so for calves you can have … my calves, for example, they’re the same size as my neck and my arms at least, last time I checked, but it doesn’t appear that way, depending on what clothing you wear, etc.

The calves in particular are very big difference in appearance, whereas the actual muscle growth potential can be quite good.

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menno henselmans calves

Mike: Yeah, that’s a good point, actually, cause looking at my calves. Flexed, they look quite different than unflexed, and even measuring them … there’s a guy that works with me who has visually more impressive calves.

And we’ve measured and we have, I don’t know, he might have a little bit of size on me, but he has, the muscle insertion point is just … for visual appearance, his is better.

Okay, so the last point, and this is something you did touch on, is so that’s in terms of size and genetics and how they play a role in response to weightlifting. What about looks?

You’ve been mentioning things, and people hear this stuff like “insertion points” and “muscle bellies” and, you know, if you could just quickly explain to people what this means, and how does it play out visually, and how do genetics influence how we’re going to work?

Like, you can have two people that just do a bunch of the same chest type training for 6 months, and why does that one person have that square, armor plate, perfect looking chest type of set up, and the other person is maybe rounder, and droopier, or whatever?

The reason why I think it’s worth touching on is there’s a lot of, there are a lot of people out there, trainers, coaches, that will claim that getting that perfect looking chest that most guys want is just a matter of training the right way.

That if you don’t have it, you’re just training incorrectly, and you need to give them money, and they’ll show you how to do it.

Menno: Yeah.

The thing is, the muscle insertion and origin points, they are fixed. You’re not gonna do anything about that. That’s the part of the appearance that’s just, you can do nothing about.

This means that some people will have longer muscles, and they have larger muscle belly relative to the bone, than other people. Which means that some people get this really full, muscular look, and when they’re really muscular, it’s like muscle all over the body just flows into each other.

A great example of that is Phil Heath, who has that everything flows into each other. Whereas other individuals, it’s more the joints, and the bones are a lot more pronounced because there is room there. A larger tendon, or a longer tendon.

For example the biceps, this is a good paraxial you can use for yourself. If you touch your biceps to 90 degrees, then you can see how many fingers you can squeeze in there.

If you can squeeze four fingers in there, for example, that is bad in terms of muscle length, and that means that even if you develop huge biceps, you can get a great peak, but it’s just not gonna cover the entire arm, so you’re never gonna get that Phil Heath-like flow.

Mike: It’s going to be more like the tennis ball look, as opposed to the football.

Menno: Exactly, so these factors, and also for your chest and for your abs, like we discussed, they’re fixed.

In that regard, the muscle shape is something you cannot do anything about. It’s also something therefore you shouldn’t worry about. If you cannot control it, don’t worry about it.

Mike: Just get the best abs you can get.

Menno: Yeah, exactly. I think almost everyone ends up being quite happy with what they’re at because, like I said, almost no one is screwed in every regard.

You might not have that armor-plated looking chest, and a full six pack abs, but maybe you have a very aesthetic back, or you do have the quad sweep, or the calves. You’re as normal as other people.

You might look at my physique, for example, and be like, “Oh look at those broad shoulders,” but then, you know, your quads or your calves might be a lot better. So, almost no one is screwed in every regard.

Mike: Yeah. Okay, great. So yeah, I think that’s a good summary of it, and I would add to that for just people who are listening again, you’ll kind of know this as you put a couple years of training in and build your foundation of muscle.

I would say, also, I think body fat percentage is worth mentioning in that, you’re gonna look quite different as a guy at 15% than 10%, or even as you get under 10%. I think, like the chest in particular, I know that with me, with the fatter I am, the more rounded my chest looks.

It’s just not the look that I like, but then if I get lean, and then get very lean, my chest does have a flatter look, and have a better look. There’s also that, just for people listening, that it’s hard to know really what your aesthetic potential is until you get into the lower body fat ranges, I think.

Menno: Yeah, absolutely. And that’s one of the morals of that is I think everyone should get lean at least once in their lives.

It’s one of the best experiences of your life to get down to a really, seriously lean body fat percentage at one point. Well, not just to achieve all these aesthetic things, but you’ll learn so much in the process. It’s truly one of the things everyone should do.

Mike: Yeah, yeah. No, I agree. Would you say though, that you know, you have to be able to give it up though too. Cause you know, there’s that now where anything if you get really lean, anything higher almost just is less satisfying, and now you have this new standard that you’ve kind of set for yourself.

Menno: Yeah. Definitely, but that’s one of the nice things you learn, that there’s always a trade off. Then you learn, a lot of people they just think “I wanna be as lean as possible,” then once you’ve actually been that lean.

Now for me, I was in constant shape for a really long period because during my last contest prep, I had to switch show, and then I had to move about seven times or so.

I ended up being basically contest shape for I think, in total, about nine months. Which it takes its toll, so. Now I really, generally don’t care about being that lean anymore. I’m just –

Mike: Got it out of your system.

Menno: Yeah. I’m in Asia now, and all these different foods are here to try, and I’m like, you know, I can get that lean again in a few months. I have all the tools, and it’s just a matter of putting my mind to it, and then I’ll do it.

But there’s no point in me staying that lean long term right now. That’s a nice thing, you get the control and you are aware of the trade offs, and it really puts things into perspective.

Mike: Yeah. No, I agree, that’s a good point. Alright well, we could probably go on for quite some time talking about all kinds of things.

To wrap up here, where could people find you and find your work? And then also you’re mentioning a PT course. I know people are gonna wanna hear about that.

Menno: Yeah. You can find basically all my stuff and my team stuff at BayesianBodybuilding.com. We’re on Facebook, Twitter, Instagram, and looking into a few other things. But those are the big ones, and you can find them all as well. We have a newsletter, so you can just check it out, see if you’re interested.

Mike: Yeah. Just I’ll throw in there that I don’t follow regularly too many people in this space, just because it’s not productive, but you’re one of the guys that I regularly read and you obviously know what you’re talking about, so I recommend everybody listening, go follow Menno. Follow his work.

Menno: I appreciate it.

Mike: You will learn things!

Menno: I hope so.

Mike: Yeah. Okay, cool. Are there any projects that you’re working on now that are coming up that you want people to know about?

Menno: Not particularly. I’m knee deep in an English PT course and a Dutch PT course, and just doing a lot of coaching at the moment. We’re expanding the social media outreach though. We’re gonna post a lot of infographics on cool, new studies.

Mike: Nice, awesome. Okay, great. I think that’s a wrap. I really appreciate, again, you taking the time. It’s been very informative, I know people are really gonna like the interview because, again, these are questions I get asked and that’s why it’s on my list.

And I’m like “I need to do a podcast, I need to find someone really good on this,” so I think you’ve delivered perfectly, so I think you’ll probably get some feedback from people.

Menno: My pleasure.

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