Do You Need a Calorie Surplus to Build Muscle? | Dr. Eric Helms

28:19But I mean, if you think about it, the the nature of kind of progressive overload, it's always bootstrapped to where you were. I think about this all the time, like someone off the street who's never lifted before, but is not out of shape. Right. And let's say they're not a really, really heavy person, not carrying a lot of body fat. If we said, hey, and let's say they're 70 kilos, like Jordan, not unhealthy, not unfit, not heavy person, 70 kilos. And you said, hey, how many reps with a 20 kilo barbell do you think they could do on a back squat if they got top form? Like, what would you, what would your guess be?

28:53Empty bar? I don't know. probably 30, 25.

28:58Dr. Jordan Feigenbaum:I mean, somewhere in that it's, it's a lot, you know, empty, but maybe more 50, you know, who knows? I, I totally agree somewhere in the 20 plus rep range, but the heaviest or the hardest set they've probably ever done is maybe a body weight set for like two, like they were on the toilet, they got up and they dropped their phone and they squatted back down and they picked their phone and that's it. So they did it twice. So they're like, okay, it's a double, it's a cluster set right so you put 20 kilos on their back you could probably have them do sets of five and because fives right you and i both know that fives are the number right for strength training and let's say they do that monday wednesday friday a single set of five for 20 kilos i would bet money that you would actually see hypertrophy over maybe a 12-week period that would be a little bit in the quads.

29:47It would be measurable, right? But they're training it like a 30 RIR for less than the minimum effective dose of what we see for three sets per week. And you're like, that can't be possible. That wouldn't produce any hypertrophy. But we know it does. Walking programs do it, right? So I think in my mind, it's a very, very long answer, but I think the unifying theory is that there needs to be some degree of stimulus relative to where you are. And that degree of stimulus is going to have a known ceiling based upon this curvilinear response yep so how much time you got to get under the weights and how well are you getting under the weights that's that's

30:28Dr. Jordan Feigenbaum:what i tell people is like generally speaking more training load will drive more adaptation where you're depending on where you're looking and the two biggest constraints one is time right logistics and the other one is what can you actually recover from which is generally kind of where does your fitness training tolerance work capacity where does all that all kind of come to ahead. And, you know, if you took that somebody's genetics, right. And assuming their work ethic was insane, you know, there's some upper limit, there's some upper limit. And then, you know, but the heuristic that people will, will distill this down to is like, look, yeah, when you're untrained, untrained or new, just new, you're going to gain more muscle mass, generally speaking, faster than as you become more and more trained.

31:08Dr. Jordan Feigenbaum:And it's like, okay, I'm with you on that. But But what I don't want people to take away from is that what's happening underneath, right? The muscle protein synthesis, the muscle protein breakdown, the accretion of protein there. You know, it's not really the rate isn't slowing down. You just can't do as much in a given time because you're getting closer to that cap. And if that cap is based on your training load, OK. If the cap is based on your training load and your genetics, you know, whatever. There's just multiple sort of factors that kind of establish that cap. Does that seem like a reasonable harmonization of everything together?

31:44Absolutely. And I think we're getting pretty close to understanding what stimulates growth, but we are still trying to determine what constrains it. You know, like why can't anabolic steroids, you know, like totally circumvent that? And and what does that mean? So, yeah, there's there's there's still much more to be learned.

32:07Dr. Jordan Feigenbaum:I thought that was going to be the most fun portion of the book, the signal book to write, you know, how to super physiological, super physiological dose of testosterone affect training adaptations. And to some extent it was like because you just you're seeing all of these sort of, quote, breaks in heuristics. You're like, oh, that's super interesting. But you're like, well, how, though? Is this mostly like a satellite cell, myonuclear accretion thing? do the myonuclear domains grow disproportionately in response to this high dose of testosterone you know what is this an energy thing because glycogen stores go up like there's all sorts of like theories and then when you look for like the outcome or the or the the study that would settle the score and you're like oh that actually doesn't exist yet okay cool well so we'll just we'll just guess yeah you know i my working theory there because there are some things where if you compare like there's very minimal differences between men and women as far as the relative proportion of muscle mass they gain so once you're past it you know despite the fact that there's massive differences in circulating testosterone right um so once you're past maturation um it's not a major player sex hormones right and if you look at uh hypogonadal men, and you probably know this better than I do with signal versus, you know, men at the high normal, you don't typically see a different response to resistance training.

33:35You see different baselines. So, and that's kind of what we see between men and women, right? After maturation is a different baseline. I think a lot of what we see is the quote unquote synergistic benefit of going on anabolic steroids with resistance training is actually seeing people gaining muscle from resistance training while essentially inducing a second puberty of whatever degree of the androgens you're taking. And then as you're rapidly gaining muscle mass, you can make the training even more effective. So they're overlaying on top of each other. But I don't actually think that the anabolic steroids are directly increasing the stimulus you get from resistance training, because we also have the base and bass and I'm not sure to pronounce the last name studies of lean body mass jumping up without training which again kind of like a second puberty and I think people get it twisted they're like man that's that that's so depressing that you know they gain just as much if not more in the in the natural group lifting you know lifting weights as the group not lifting weights on anabolics and it's like it's a little different you know They're going to reach a new baseline and then plateau.

34:45And that, I think, is what we're seeing in a lot of these cases. I do think there's a distinction between mechanical loading-induced hypertrophy or detraining-induced atrophy and potentially hormonally-induced changes in lean body mass or even energetically -induced losses of muscle mass. So more to uncover there. But I would not be surprised if, say, muscle memory exists if you lose muscle because you don't consume enough calories or protein. But maybe it is not really a thing from purely changes in mechanical loading. And we just kind of, you know, fluctuate from there.

35:28Dr. Jordan Feigenbaum:Muscle memory, yeah, it's another super interesting avenue because you see a differential sort of relationship. If it's like a in like spinal cord injury patients, for example, now their muscle memory and detraining that sort of works versus people who've like, oh, I just stopped working out for a long period of time versus other people. There's some sort of chemical, you know, hormone mediated detraining. It's even one of the scenes studies. He they chemically castrated men before giving them various doses of exogenous testosterone. and there was this robust response even in what would be considered like low normal testosterone levels and there's people like see see look you just a little exogenous testosterone goes a long way and you know these people went off to the races and it's like what they came from hypogonadal so there's some sort of like resetting of of things that happen there and it's super physiological doses i i'm inclined to agree with you that there's another reset but yeah men and women usually exit puberty with different amounts of muscle mass, and because men typically have more muscle mass, they end up gaining more in absolute sense, but the relative improvement between men and women, despite large differences in testosterone, is effectively the same.

36:44Dr. Jordan Feigenbaum:So that's the stimulus side. The ceiling moves with the training. If you train more, the ceiling will go up. If you stop training, the ceiling will come down. That holds for the astronaut coming back from six months in orbit and it holds for the guy doing one set of five on a Monday which sets up what we actually came here to discuss if training sets the ceiling what does energy do the standard advice says you can't get near that ceiling of growth without eating in a calorie surplus I don't think that's quite right and I want to talk about why if you had to give people like a how much muscle mass can I gain in a day how much contractile tissue could I gain in a day somebody who's new to lifting weights and somebody who's more experienced, where would you kind of put that ballpark?

37:29In a day. Well, we could work back from, let's just say, you know, four pounds in two months, you know, something like that. So it's half a pound a week and that's a wet muscle tissue too.

37:41Dr. Jordan Feigenbaum:So let's put a number on that. Half a pound a week is about 227 grams. So spread across seven days, you're looking at roughly 32 grams of wet muscle tissue a day let's call it 30 and wet is an important word here because muscle is about three quarters water the actual dry protein you're laying down is closer to eight grams a day give or take the whole point is what is the cost of building that right calorie wise and before we we started recording there are a few preprints out calculating okay just the cost of building the tissue, right, the tissue itself, there's another preprint about, okay, well, what about the tissue plus the exercise required plus the changes and other aspects of metabolism?

38:27Dr. Jordan Feigenbaum:When you think about the energy costs of building muscle tissue, though, is there a series of numbers in your mind as far as like what this actually costs? I think there are from a mechanistic perspective. And that preprint is awesome. Big shout out to Nikolaitis and colleagues. This just came out last month where they've done a pretty damn good job of building a model, I think, of all the things that would contribute to it. And then to the best of their ability, they've done a, hey, if this was true, what would we see? And I think that's a really good way of thinking through conceptual but still evidence-based concepts as a general epistemic recommendation is all right if this is true what would we see in the world and what things would prove that wrong and that gives you hints at where the hypothesis is at least limited right so they come up with a number that includes like five different additive components so the stored tissue energy which that is kind of what I was talking about earlier.

39:36Like if I want to back calculate, if I've got you in a look at the DEXA scanner and I know my reliability and I can say, oh, you know, or at least the group level, maybe I can say, was this a group in a net surplus or deficit? I can know literally nothing about their activity, their exercise, anything about them. I can just look at the change in fat mass and lean mass and knowing the energetic stored tissue energy of lean mass and fat mass in the way that DEXA calculates it, I can back calculate whether they were in a net deficit, that group over X amount of time, right? So the values that you would use there, that's the stored tissue energy, but there's a lot more to this, the stored tissue energy.

40:23Fat mass is a little more simple because adipose tissue is not fat mass. Fat mass is literally just the fat, which is 100 % fat, right? Adipose tissue is, you know, 85, 90 % fat. And the process of storage is very energy efficient, right? So the difference between the stored tissue energy and the cost of building adipose tissue, and especially the cost of liberating it, is they're much more close together. But the stored tissue energy of lean mass, or especially muscle mass is actually quite different than everything else. So after that first additive component, then there's the biochemical synthesis cost.

41:06It's actually generating all the components that go into wet skeletal muscle, right? Then there's the physiological deposition cost. And that is the process of actually taking what you built and making it into muscle, which is separate in the way it was conceptualized here. And then there's the kind of what you were, maybe you didn't realize it, but you were alluding to is, you know, we're gaining less proportionate muscle over time as we continue to lift. But as soon as you reduce your training dose significantly, you're going to regress, right? You're going to lose. It's going to be a detraining effect.

41:42Your minimum effective dose to be a top level bodybuilder is higher than it is to not be, you know, measured as technically having sarcopenia, right? So we see the same thing in every adaptation. Like if you look at the minimum effective dose to take an untrained elderly person and increase their VO2 max at the fastest race that's been observed, that dose is less than what it takes for a elite cyclist approaching a 70 VO2 max to maintain their VO2, right? And there are several case studies of weightlifters at the national level or power lifters, a case series where they go through a traditional periodization protocol and they go through a taper and they see their volume kind of decreases, intensity goes up.

42:28And there's measurable losses in lean mass while doing what would be a robust strength training program. And of course, their strength still peaks because there's a lot of things that go into what are on strength and not all of it's just muscle size. So we can see that the floor lifts as you approach your ceiling. And so there's the physiological deposition cost and there's the resting maintenance during accretion. I have to maintain what I've got while I'm building. And that should be counted because it's still going on in the same muscle. Like you said, you're expanding an individual fiber, right?

43:02So that fiber still got to be there, you know? And then finally, there is the diet induced thermogenesis. So to take, you know, the chemical energy from food and then translate it into changes structurally in the body, there's a cost of that. And we've known that for a long time. And we kind of go, hey, 10 % of whatever you're consuming. And that overall number is about 3 ,500, but not for pound per kilogram. Per kilo, yeah. Yeah. Now that is really cool. And then they compared that against animal models. They looked at drug models. They looked at even lab-grown meat and studies in that world, like people who trying to, you know, make it so that you don't have to get a Beyond Burger.

43:43You can actually just grow, you know, beef. And then like, are you a vegan? I don't know. That's an ethical question. And comparing it to multiple things, you know, animal studies, feedlots, chemical studies, industrial types of studies in that regard and going, okay, these don't get at every single one of these components. But when we look at them all together, they seem to comport with this number. And they even provided variants on it, which I loved. You know, it's roughly 32 to 3 ,700 calories per kilogram to build that tissue. But the reason why I think it's only a theoretically useful number, because who says you can build a kilogram in a month, right?

44:21You don't actually know where you're at on that curvilinear process. You also don't know how effectively you can stimulate muscle growth so that you're maxing that out. And then if you're in a surplus, is your body going to decide to use all of that surplus to build muscle? Or is there an obligatory increase in fat mass? And that seems to be impacted by energy availability. So potentially, like, are you in a state of approaching reds? Are you super fine? Or are you well above your personal fat threshold? Or are you well below it? Are you in what we would describe as the quote unquote non-regulated, you know, point between your two intervention points of the dual intervention model?

45:14and all of that interacts together to dictate what is the rate of muscle growth you can have

45:20Dr. Jordan Feigenbaum:just to make sure everyone's on the same page with these two terms the first one being reds which stands for relative energy deficiency in sport that's what happens when an athlete's intake doesn't cover their training plus their basic physiological needs and it persists long enough to cause problems so hormones get disrupted bone density suffers recovery gets worse and yes you tend to lose muscle. So when we say reds from here on out, we're talking about relative energy deficiency in sport. The second is the dual intervention model concept. So this is Dr. Speakman's idea that there are two body fat levels that your physiology actively defends against going past.

45:59Dr. Jordan Feigenbaum:There's an upper limit, which pushes back on carrying any more body fat. And there's a lower limit where it pushes back on carrying any less. And in between, there's a range that it doesn't seem to care about which lets you drift this sort of unprotected zone so this middle range is where most people actually live energy only becomes the constraint on building muscle once you drop below the bottom limit now i should say that this is admittedly speculative that this sort of body fat or bottom constraint set point is the same for overall body fat as it is for muscle hypertrophy. It could be that these two are different, but conceptually, this is where I think we both land here.

46:41So you could have the same person look at that study and in two different parallel worlds, one of them is going to train three times per week with a decent protocol so that they're able to gain, let's say a kilogram every three months. But the other person reads that paper and they're like, sick, I train six days a week for two hours and I am trying to win the Olympia, right? And they might be able to gain, you know, sometime in 10 years maybe, and they might be able to gain at that early point in their career, four times that rate of muscle for those two months. So one could overshoot it and gain fat.

47:17One could undershoot it and experience body recomposition because they created a stimulus for the muscle to grow, constrained it a little bit and their body went, well, damn it. Well, okay. I got to tap into my savings. And we see that in the literature when you have incidences or, or I should say a study design where someone has the capacity to grow very quickly, but then constrains the amount of growth that they can achieve by not providing sufficient energy. And then one group might experience pure muscle growth and the other group might experience a mix of fat loss and some muscle growth. And I think the greatest example of this is some of the early, early bulking studies from the mid 2000s.

47:57They did this with university trained males. They'd had three groups. and one of them was just told to maintain their habitual diet the other two were given a 2 000 calorie shake on top of their habitual diet that was either pure multidextrin or a mixture of multidextrin and protein and they brought them in and they trained them hard four days per week on a hypertrophy program with what i would describe as moderately high volume pretty close to failure And the two groups that got that 2000 calorie weight gainer, they gained three kilograms ish on average over eight weeks on this group level stuff with no change in fat mass.

48:37So pure three kilogram gain of that. And that means their body fat percentage went down. However, when you look at the non-significant, quote unquote, changes in the control group, same training protocol didn't feed enough for it. they lost like almost a kilogram of fat mass and I think gained a kilogram and a half of lean mass. So like barely saw scale weight change, about a pound, but they were actually in a slight deficit and their growth rate was constrained to about 50 % of what it hypothetically could have been as an untrained lifter on that protocol because they had to go through the inefficient process of tapping into their fat stores to kind of offset that energy cost.

49:20And that constrained their growth, even though it was the same protocol. So that's where that example of, if those guys had all been given that paper by Nikolaitis all the way back in, you know, 2002, if I recall correctly, Rosnick and colleagues, by the way, for anyone who's interested, it wouldn't have helped them, you know, necessarily because they don't know how fast they can grow.

49:41Dr. Jordan Feigenbaum:Yeah. Yeah. I think, I think that's a important point. It's like you're trying to, if the goal is to maximize hypertrophy, right? You can, you almost can't know did i max this out unless it's post hoc and you have like some compare that is somehow similar to you it's a twins training study uh for example and it's like well we actually gave this other person more more uh more mass and so perhaps that is maybe one of the origins of the heuristics here right if if we're we're circling this idea where your energy availability sort of um that is one constraint for muscle growth there's a stimulus constraint right how much training you're doing And then now there's an energy constraint.

50:19Dr. Jordan Feigenbaum:There's going to be genetic constraint. So some constraints here. Right. But the energy constraint is about how many, how many, how much, how many calories basically do you have available to you? You can predict based on some other heuristics we're going to come to here in a few minutes, but you couldn't know unless your evil twin was in the other study arm and they got a different amount of energy, more or less or whatever. And one of you would figure out like, oh, shoot, I actually had more potential here. So I think maybe that is like the origin story of this heuristic where it's like, look, you want to gain muscle mass?

50:51Dr. Jordan Feigenbaum:It's being a surplus. Just stop worrying about it. You know, and it's like, look, now we're covering. It's almost insurance at that level. Does that seem reasonable? You can remove 100 percent. You can remove that constraint. And I think the issue is, is that if you remove that constraint and your training is shitty, then you will just gain body fat. Right. And I think that's where some of this overcorrection of like bulking is dead has overleveraged the research. And my own study included that came out in 2023. Like if we look at the research by, as Americans, we'll pronounce it this way, Garth.

51:29Garth, not Garth A.

51:30Dr. Jordan Feigenbaum:Yeah, exactly. Or whatever it might actually be. You know, there's a 2013 study where this was first kind of on the radar where everybody's mostly relying on Rosnick and saying, hey, look at this. You know, you should be throwing 2000 calorie weight gainers down, double your gains over eight weeks. But maybe over leveraging an example of young university aged males being trained much harder than most of the time that is occurring in the literature. And then we see actually a similar protocol, four days per week, you know, upper lower split. but it's on top of these athletes sports conditioning and they're elite athletes so they've been doing some strength conditioning and they get dieticians who follow what i would say is the heuristic and they advise them to be in the intention of like a 500 calorie surplus over a customized period of time for each athlete so it's a very translational study right and then they tell the other athletes and again these are not bodybuilders right who were raised in the same era as you and I, there are, you know, a bunch of different codes of Norwegian athletes.

52:33So high level athletes are not thinking I need to like bulk, you know, that's, that's not in their terminology. They're thinking, Oh, if I want to gain muscle, right. Then I'm going to lift and I'm going to let my training do its training. They're not reading flex magazine again, this is, you know, 2013. So what did they do is they just kind of followed their habitual diets. Then they were in a very slight surplus and the disparity in the actual measured calorie intake between the two groups on average was about 600 and you saw non-significantly greater gains in lean mass and one rm barely in the group that was in a 600 calorie surplus but significant within group changes for lean mass and one rm strength across various uh you know metrics in in both groups and then hilariously poor jump height and sprint times in the group that was in a larger surplus Yeah, because they gain more weight and the composition of that weight was almost entirely body fat.

53:28So they clearly overshot with this heuristic being elite athletes and trying to balance it with other things. The constraint was surpassed probably the first additional 50 calories they had more than the other group. But you only knew that in retrospect when you looked at it. Right. So I think that's a great example.

53:49Dr. Jordan Feigenbaum:It's the same thing as like a training response, right? You have the perfect program on paper and you're like, look, I've checked in all the boxes. I've got this training load. I've got this proximity to failure, this exercise selection, rest period. It's all T's are crossed, I's are dotted. You can only know if you maximize your response afterwards, but where's your control? Where's your evil twin doing a different program, right? Unclear. So really working on trying to get that twin situation going so I can figure this out finally. Take down the master's class. Let's go. You got to watch dark matter that that's that that if you want watching that show, it's amazing.

54:23Dr. Jordan Feigenbaum:We're on it. Yeah. So, OK, so let's say you can gain a kilo of muscle per month. All right. And that puts your rate at like 30, what, 33 grams a day of total muscle tissue. And that's wet tissue. Right. And so, OK, well, now it's 25 percent of that. So we'll call it 10 grams of actual like lean contractile protein. the nicolitis paper suggests well look you only need 115 calories a day to do that right and so through this model this uh central organizing theory we're trying to work towards that would mean you would own that your energy availability constraint then would be do you have an excess of 115 calories from somewhere it could come from the diet or it could come from your endogenous fat stores and like an 80 kilo dude this 20 body fat has we'll just say a lot of fat energy stored that's 123 was something 100 000 plus calories just sitting there and so without any other further explanation and say well look you don't need to really be Plus 500 calories from your maintenance level intake.

55:37Dr. Jordan Feigenbaum:You could just keep doing what you're doing and train hard and you probably have enough energy on board to maximize your rate for a given stimulus. Does that seem reasonable to you? yeah i mean that is absolutely theoretically true and i like the caveat that we're talking about people who have plenty of body fat because i think that is perhaps the the next maybe i'd say moderating factor we need to consider as far as calories because that same person when they're like let's say they did a bodybuilding show and they're shredded um the story changes even if they had the exact same relative muscle mass to their quote unquote ceiling for the given stimulus they're on.

56:22So whether you want to dig into that next, but I'll let you lead where you want to go.

56:27Dr. Jordan Feigenbaum:Yeah, yeah, we're going. But the thought would be, look, that's a kilo a month. But what if this person is more well-trained, they're closer to their ceiling, and now it's three months where they're gaining a kilo of muscle? Well, now it's like 40 calories a day. And you're like, who doesn't have 40 calories a day excess? And it's like, well, what if you're really lean? So so this is where my brain went. And again, therapy needs notwithstanding. When it comes to the energy constraint for hypertrophy, I can't I come up with like two big buckets. One is like a systemic energy constraint, which would be calories from stored energy.

57:06Dr. Jordan Feigenbaum:So body fat primarily and dietary calories. And then like a local energy constraint, which would be protein. I understand it's not local that protein does go everywhere, but you could effectively have somebody with enough calories coming in or calories stored, but too low of a protein. And they're like, well, shoot, we don't even have the raw materials here. So I'm going to call that a local energy constraint. Yeah. The thought would be how do we establish cut points for like this is probably where we're approaching that sort of leanness constraint. So energy availability is now a little too low to rely on endogenous sources.

57:43Dr. Jordan Feigenbaum:How do we establish that? And further, does it change when we start changing the other part of the systemic energy availability coming in from the diet? So we had 100 calorie per day deficit versus 1 ,000 calories. Like, well, shoot, these are two different sort of worlds here. How would you go about coming up with those cut points and where have you landed, if anywhere yet? Yeah, so we did, you can kind of interpolate some mechanistic research on this and then some larger scale meta regressions, one done by Murphy and colleagues. And then one that I was really privileged to be a part of, led by Ruffalo that I did with Dr.

58:22Trexler that looked at basically redoing my master's, I mentioned at the start of the podcast, but quantitatively, where I did like a systematic review where I argued that in states where someone is training lean and also in a deficit, maybe you should have a higher protein intake to offset the costs of those local constraints. And I think, you know, the local constraints come from being too lean and not having enough energy because your body will start deciding, no, we need to use a different account here or maybe even get the credit card out type of deal. So the, uh, the meta regression is essentially looking at the interaction effects.

59:06And one of our few significant moderators was when we broke body fat percentage into tertiles. So, uh, three different tiers of high, moderate, and low. So for low, we just, we, we, we did this based upon the data we had. Um, but we had under 12 % body fat for, for men and under roughly 20 % for women. We kind of just added like seven or 8 % to the value. Um, and then grouped. So it was like, so it wasn't just an overlap of the, um, the sex-based analysis in this, um, moderator. So we looked at what was the, the slope of that protein intake to where you saw maintenance of lean mass, um, or even gain in lean mass at higher protein intakes with each one of those body compositions.

59:53So we had under 12 % for men. And I'm just going to say it for men and I'm sorry, but then just add 8 % in your brain so I can be a little more efficient in my speech for women. So under 12%, under roughly 20 % or over 20 % body fat were our kind of three tertiles. And I think I've got that right on the paper in front of me. And the slope changed and where it intersected the line of protein intake to have no muscle or no lean mass change over the observation period shifted as well. So it left shifted, right? The higher in body fat you were. So what we saw was that when you're over 20 % body fat, it kind of doesn't matter.

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1:06:340.6 or higher, you're seeing very marginal benefits that are unclear. But when we were talking about the leanest tertile, with, of course, the middle one looking very similar to the average, because that's the way math works. When we talk about the leanest tertile, people under 12%. Now, it wasn't 1.9 grams per kilogram that was the average intake where you didn't see losses of muscle mass. It was like 2.5, right? And also, the shape of the slope was different. So you weren't getting much out of the high protein intake. And the question is, well, what's going on here, right? And that's just protein.

1:07:11But when we look at this much larger metaregression that was done a couple years back by Murphy and colleagues, they took a whole bunch of studies and they looked at a similar calculation of when do you lose muscle mass and when do you see a reduction in or I should say lean mass from being in a certain scale of deficit. And their kind of inflection point was 500 calories with massive distribution, by the way. So it's not a useful rule. And then as you got closer to a maintenance energy intake, you would see much more occurrences of gaining muscle with resistance training. And there are blips all over the place.

1:07:54But what it showed was essentially in that kind of like 100, 200, 300 calorie deficit range, very common for people to experience body recomposition. Because if you're in net deficit and you're gaining muscle, where is it coming from? Fat mass, right? Right. So that is intriguing. But then it's even more thought provoking when you dig into who were the people in these studies and the vast majority of people in this, you know, Murphy metaregression were what we would describe as untrained. They were performing what we would describe as a very low dose resistance training protocol. And they were also, on average, what we would describe as borderline class one obesity, or at least overweight was kind of like that point there.

1:08:44So that is a little of a different story than when we look at like lean people who are already, you know, lifting weights. and then what is an appropriate energy intake and protein intake where they don't see muscle loss. And that changes as you get deeper and deeper and deeper into a contest prep or get leaner and leaner and leaner. When we look at case studies and we have time series data for individuals, which I think is really cool. So why is the question? And that's where we shift to the mechanistic data. And there's some really cool stuff that was done, probably wouldn't get through an IRB or an ethics board in modern times that was done in like 60s, 70s.

1:09:22And man, we could talk about the Minnesota starvation study, but there is some total starvation data. So where they don't feed somebody for days and they have this in people who are actually quite lean. So we're talking single digit body fat percentage, as well as people who are class two or class three obesity, very high in body fat. And there's a really immediate shift in substrate utilization, minimal changes in people with obesity or at least men in this data. but a two to three fold increase in various metrics of what I will essentially describe as using protein for energy, either direct oxidation and muscle or like basically maxing out what the liver can do as far as converting protein into energy, you know, getting ketones, you know, gluconeogenesis, all that stuff.

1:10:11So leucine oxidation doubles or triples, gluconeogenesis doubles or triples. So what you're seeing here is that when you don't have sufficient energy, protein moves from being that local you know like kind of primarily used for build and repair to hey we're taking any and all comers credit card uh you know i don't get high interest loans whatever because i need the energy right now because i don't have anything i'm not eating anything and i can see my savings account is low so you know i need to preserve a little bit of glycogen so i can you know run from the proverbial tiger if we're thinking from evolutionary biology and that's probably why a higher protein intake seems to have a slight benefit for lean mass preservation and a deficit the leaner you are.

1:10:55It's because the leaner you are the more the body is looking at that local constraint and going I'm no longer interested in building this up I want to tap into it as the emergency fund and you can see that even when you correct the energy side of it, there is a lag period and a necessary gain of body fat before you're going to see increases in lean mass. Like Trexler actually, and as part of his graduate work, had a study that looked at natural bodybuilders, a small cohort of them during the post-contest phase for about two to three months, depending upon the individual. But at least about, I think, 10 weeks of data, if I recall correctly.

1:11:35And they, of course, go into a large surplus and they gain exclusively body fat, at least for what can be measured. And any lean mass is probably attributed to glycogen and water, right? So this tells you, okay, the constraint for why this person couldn't gain muscle, and in fact, probably lost some on the way down through their contest prep, was energy availability and a progressive increase in the body, not thinking about, this is not storage time, I'm not going to build muscle. And then even when you remove that constraint, there's a period of time where it's like I need to get at least to a higher threshold of body fat before I start correcting this system to allow that to be something that's tapped into.

1:12:23so this goes like all the way back to um our definition of surplus deficit and and maintenance and i think if you use those same heuristics but you apply them to the specific tissue you're interested in now they work so if you say that a surplus for muscle tissue is when you see a gain in muscle mass when that tissue is allowing that to come in and will use it and has a sufficient stimulus to grow. Like if the conditions are met where muscle mass could increase and you're in a surplus, then you will see an increase in mass there. But same thing is true of body fat. And even though I could describe these as a conceptual model as two separate systems to where, hey, the fat mass is in a surplus if it's growing and the fat mass is in a deficit if it's decreasing or at maintenance if neither one is happening in net and the same thing is true of muscle they're both connected to the same stomach right and the same hp uh you know g a whatever axis you want to talk about that's going to dictate which one gets priority and which one is used as an energy deposit source or an energy sink and that even changes throughout the day but all of those constraints go together like what is your rate limited um muscle gain potential heavily influenced by how close you are to your current ceiling?

1:13:50And then what is your current body fat that's going to dictate how much priority and access and use of those stores of tissue will I potentially use for energy or energy deposition? Am I going to build muscle? Am I going to use it as an emergency fund? And then how much am I eating? What's the exogenous amount coming on

1:14:11Dr. Jordan Feigenbaum:board which influences that as well yeah yeah the way i think about where kind of the there's like a bridge between skeletal muscle and fat tissue they are obviously coexisting but also talking to each other yes maybe not directly uh uh for for much of the sort of relationship but through the brain certainly where the fat is sending signals out um and when you get lower than a particular threshold, the body's like, Hey man, we don't have excess here. In fact, we're, we're probably below where we need to be. I'm eyeing up that muscle. And you can offset that by taking enough dietary protein to say, well, look, all right, we don't have to sacrifice the muscle yet, but only because you're eating a ton of protein.

1:14:55Dr. Jordan Feigenbaum:And yet you're still constrained to some extent for building new muscle tissue. You're just not sacrificing what you currently have. And I think that's probably why you see that different curve and the different shape when people are getting leaner. But it brings this question back. Are you telling me that we can use our own fat to build muscle? Is this really what you're saying? And I want to be clear, you're not saying we can transform fat into muscle any more than we can transform muscle into fat. Can't do that. But Are you saying we can use our own fuel from stored body fat to build new muscles?

1:15:34Dr. Jordan Feigenbaum:Is that what you're saying? Yeah. I mean, think about it this way. Once amino acids, triglycerides, or glucose gets in the blood, where it came from or how it got there sort of doesn't matter. It's going to be then dependent upon where does it need to go. and um even if people struggle to accept that you can uh use fat to build muscle in that maybe description of kind of like in the blood it isn't going to get them there maybe you're more of an empiricist like me let's let's talk about one of the most recent useful tests of this that kind of tells you maybe the magnitude and the conditions so there was a great study that was recently done by Vargas Molina, right?

1:16:17They took these two groups of literature-trained individuals. So what I would describe as late-stage novices, right? Also importantly is they were mostly men, and I only say that because it was a mixed-sex study, but this tells you, it helps you understand like what their body fat percentage means. Because I tell you that they were all in their low 20s body fat percentage in both groups on average. If that's women, they're lean. If it's a mostly male group, you go, oh, now we're actually talking about that high body fat quartile from the meta regression that Ruffalo, Trex, and Helms did, right?

1:16:51So what we're looking at is a group that is relatively high in body fat, but not unhealthily so, but body fat's not the constraint, right? They're at maybe their upper end of their intervention point or something like that on average. And they're trained, but they've got a lot more they can go. And, you know, despite popular beliefs who think of certain people who think that lab training studies are easy and they are, you know, like cookie cutter nonsense. They are cookie cutter hardcore. And even if they're low frequency, only two or three times per week or whatever, and this study actually had a decent training protocol, you're getting pushed very hard by multiple grad students who are very interested in getting their master's or PhD or helping their PI and making sure that everything is well So if it says you're training the failure, they want to observe failure and on every set, every time.

1:17:41So things are held constant. So anyway, eight week training protocol in what I would describe as late stage novices, relatively high in body fat. And the intention, what the prescription was, was to give one group maintenance and then one group a deficit and to see which one was better for body recomp, right? Because this is one of those things, you know, the researchers are actually responding to the lifting communities. theory or what is probably a heuristic of saying, hey, train people who aren't high in body fat, they can't recomp, you know. And they need to be at maintenance to recomp because a deficit is too much of a downward pressure signal.

1:18:19Now you're creating a constraint. But what did we actually see? Well, good news is they had DEXA-derived body composition. And like I mentioned earlier, you can back calculate what happened over those eight weeks in these two groups and actually get objective solid estimations, at least at the group level, based upon fat mass and lean mass energy composition, which is something that's like a five to six fold difference in the way that DEXA calculates it. Because DEXA groups glycogen, lean mass, bone, water all together, and then fat mass is like the pure triglyceride or lipids. And they went, okay, hey, the actual deficit was closer to like 350 in the group that was intended to be in a deficit.

1:18:59and the maintenance group actually was in a slight deficit at well. They were in 150 calorie deficit ish. And what happened also is they both gained about a kilogram of lean mass over this eight week period. So they're actually matching our kind of, you know, normal rate of muscle gain and a reasonably untrained person that we talked about and energy constraints were not the, we're not, we're not there. So between, and this matches up exactly well with the meta regression by Murphy and colleagues saying, hey, it's right around a 500 calorie deficit where now you're not gaining muscle. We see no constraint difference on average.

1:19:38And this isn't a huge sample size study, but if we assume the sample size was decent and it was, and they were well randomized so that we had an equal distribution of training age and that the average deficits and surpluses or rather average deficits in two groups were reasonably close to, you know, there wasn't massive heterogeneity there, then we can look at that and go, okay, so if you're a late stage novice who has a 20 % body fat as a male and you go on a pretty good training program within a 100 to 400-ish calorie deficit, that's not going to be the constraint to how much muscle you can grow.

1:20:14We don't have a third group who is in a surplus to see if maybe they got even more, but these two things were similar enough to produce a similar outcome of roughly a one kilogram, a non-significant difference in lean tissue. So what happened to the rest of those calories? Again, this is where it's helpful to look at these two different systems. So how did they gain with less energy the same amount of muscle? Well, guess what? The group that was in a higher deficit lost more fat mass. And that's how you actually calculate the fat mass. So it's not like an aha. It's literally how I figured that out.

1:20:46But you see same lean mass gains and then a proportionate amount of fat mass lost based upon the size of the deficit. And the one kind of reality check here, if maybe you're not buying into this whole back-calculated energy surplus or deficit net based upon body compositions, that the group intended to be at maintenance was in a much smaller deficit of roughly 150 on average. And the group intended to be in a deficit was, but maybe not exactly the intended deficit they wanted to put in. And this is human research. You can try to be as exact as you can. And we ran into this in our study as well, but you're going to get something close-ish directionally, hopefully where it needs to be, but a good degree of variance when you have people in the free living condition, trying to track calories, label accuracy, metabolizable energy, not matching actual energy, memory recall, that good stuff.

1:21:43So needless to say, I think a good answer to your question, Jordan, if we're like, okay, well, at what point does, you know, body fat and energy availability become a constraint for muscle tissue interacting with the surplus size or the deficit size? And can you burn body fat to build muscle? Here's an example that fits somewhere along this very complex interacting curve where we go, well, I don't know. But if you told me, hey, I'm 25, 20 percent body fat and I've been lifting for a year, I would say don't worry about it. Don't be in a huge deficit. Keep it under a 400 calorie deficit and you'll probably grow just as well as if you were in a 100 calorie deficit.

1:22:28Dr. Jordan Feigenbaum:Could you maybe grow a bit more if you were in a maintenance or surplus state? Maybe. But I don't think we're going to see this nonlinear response once you get to like zero. You know, all of a sudden now you can gain two kilograms. I doubt it. I don't think that would hold up. Yeah, I think if we're establishing a sort of energy constraint, I think it's important to note that there's that's probably also tied to the stimulus constraint in a way. Meaning that if you increase their training load, assuming they could tolerate it, right, not get injured because they're outkicking their coverage, for example, then perhaps at that point they need an even smaller deficit.

1:23:04Dr. Jordan Feigenbaum:or they would respond better to a small surplus because now you're sort of changing the underlying assumptions and then the case here. But I think that's a reasonable like point to make. If you maybe establish the two poles here, right? So for guys, 20 % body fat on the high end, and maybe we'll call it, I don't know, 10%, 12 % on the low end, right? It's like, okay, look, If you're above 20 % and you're thinking about a modest deficit and you're reasonable, you're not like, you know, a world beater. You haven't been doing this for 15 years where you're really trying to max out hypertrophy. You could probably do a small deficit and you can probably recomp.

1:23:46Dr. Jordan Feigenbaum:And I feel generally confident in saying you're not losing muscle mass gain potential by doing that. If you said, well, what about a thousand calorie deficit? I don't feel so good about that. Okay, so we're going to kind of put this floor, we'll call it 500, whatever. If you go to the other extreme, the other pole, very lean person, 12 % body fat for a male, for example. I'm not confident that you're going to gain as much muscle mass in a deficit or a maintenance as compared to being in a surplus. And that would be a good use case for like a small surplus. The point is, it doesn't need to be a massive surplus.

1:24:22Dr. Jordan Feigenbaum:We probably don't need to do a dirty bulk, you know, as we're affectionately referred to. Unless it's a that's the behavioral sort of thing where it's like, look, we can't because 100 calorie surplus, 200 calorie surplus, very challenging to establish and also like to continue. So maybe we just end up having some insurance and now we call it a 500 calorie surplus. The heuristic kind of shows its face again on that end. I think that's where I kind of land here. And if you're in the middle, it's more uncertainty. I just yeah how do you how do you maybe square square the the the the circles and what we're talking about in the middle right most people are going to fall in the middle yeah great question and I think here is where you can also check like okay if the way you just described it Jordan is the way it operates then what would we see in the real world and what are good kind of natural tests of this.

1:25:14So, you know, the, the really lean person who's trying, who's acknowledged, like you said, man, I can't gain muscle in a deficit, uh, really struggling to gain muscle, even at maintenance. And I don't need a huge surplus, but I need something to grow. They find themselves then gaining weight, right? If they want to keep progressing. So what's a good natural experiment for that weight class restricted strength sport, right? That's right. And one thing that I think you and I, we probably follow the IPF reasonably close. There's been multiple examples of people who have, if they want to improve, they've had to actually go up a weight class and they've been constrained.

1:25:55And then we see basically this elevated baseline all of a sudden, a rapid rate of growth in terms of strength and visual changes that would, you know, indicate there's a muscularity there. Once they finally stopped trying to like, if you're trying to address the constraint of, hey, you're walking around 8 % body fat by eating an apple a day on top of your maintenance and then just cutting harder every time you have to do nationals or whatever, you're eventually going to run a runway and you're going to be just flirting at like you're bumping up against the ceiling and your cuts are getting harder and harder and harder because you have to lose more water for the level of body weight that you have that's becoming increasingly lean mass.

1:26:33And that means you're experiencing a slow downward shift towards your low end intervention point. And as you're trying to accommodate that, you're getting more signals from your hypothalamus of you essentially being in a status of low energy availability. And the only solution is not eat that apple, but actually to go up a weight class. So Taylor Atwood, you know, Panna, we see multiple instances of this. Evie Corrigan having a campaign at 52, cutting down from 57, but basically being pretty much flatlined around a 480 total once she made her initial gains and then boom, hits 500 when she goes back to 57.

1:27:14I see this over and over and over and over again. And weight class restricted strength sport and IPF that is drug tested is a really good natural experiment of having these constraints in place and seeing even super high level elite level power lifters making gains. And that doesn't break the rule of, hey, once you're close to your ceiling, you can only make very subtle gains. And it's not technique that's making them better at squatting. It's actually proving the rule of saying the main constraint that's holding you back, if you address that, you unlock the next level. And all of a sudden these people are like, like a breath of fresh air for their body.

1:27:49I'm gonna allow you to maintain the appropriate level of lean mass that we could have for your energy status once your body fat is higher because I'm not constantly pulling from it to keep you where you're at and balance the checks books, right? So that's the lean person example of once they get into the middle, all of a sudden the constraints come off, they have a uptick in the rate of gains and then it starts to get curvilinear again. And I think another really good proof in the pudding here is that if it was true that it was just always the same ceiling height and natural bodybuilders like myself, for example, you're really close to it.

1:28:31And then unfortunately during prep, because you have to get shredded, you lose two kilograms of lean mass and it's unavoidable. You would never be able to compete two years later at the same stage weight or slightly higher. Right. So this is not a mechanical loading induced loss of muscle mass. It's the energy constraint. And when you fix that, that gets kind of recorrected. The baseline comes back up, which is why I think it's a little bit different to lose muscle from a change in energy availability or energy intake. and boom, next year or two years from now, you can compete at the same stage weight or maybe a couple hundred grams heavier.

1:29:09There's no way for me, for example, I experienced this myself. I was on stage almost two kilograms heavier from 2023 to 2025. I've been training since 2004. If what took me to gain back the one point, whatever I lost and then gain 1.9 on top of that should be impossible with if we kind of held these fixed models rather than kind of have this constraints based understanding so what that means for an advanced lifter like me um is that once i get to a body fat percentage that's in that kind of middle range like you said i basically don't need to worry about a surplus the constraints not my body fat and i can only grow so fast doing everything perfectly i'm making a fraction of the gains that i had even as an intermediate.

1:29:57So like, even if we, like when I say, Hey, I put on two kilograms from 2023 to 2025, no one cares about that as like an Instagram transformation period. People see that in six weeks, right. For their untrained clients coming to their, their personal training studio. Right. But you know, who does hit me up is every other 30 plus natural bodybuilder who's trying to get their pro card or compete at the pro level. I'm like, bro, what'd you do? And I can show you the DMs. It's hilarious. Cause it's like, Oh man, he, he cracked the code. Right. You know, But what is that over a 24-month period? It's grams on a day basis.

1:30:33So once I get out of, quote unquote, the constraint zone of my body fat being too low, then it's just like eat. If I'm on 100-calorie deficit one day, 100-calorie surplus the next, it doesn't matter. I just don't want to put on body fat so much that when I diet down next time, I've got to take an extra month to do it, right? I kind of was in a purposeful surplus until I felt, and actually I have blood work on it, that my physiology normalized. And then I'm just following my habits that ensure a sufficient energy intake, ensure a sufficient protein. And I'm not thinking about whether I'm in a surplus or a deficit because I don't need much energy to grow at this unfortunately slow rate that I'm constrained to as an advanced level lifter.

1:31:18so that's another example of the interaction between being in that mid-range body fat and then being an advanced level lifter and having enough calories to play with is all of a sudden maintaining or body recomp and slowly just kind of staying around the same body weight but making it look better and better and better is the way to go so what i am noticing now is i'm flirting in the low 90s or like the low 200s if you will but right now it's the best i've made that body weight look because I'm kind of coming in and out of surplus maintenance over time. And if my training is doing its job, then I start to get hungry again.

1:31:54Once I'm closer to like, say 10 % body fat, and then my body would start to creep up and I'll look, you know, better than I did last time at that body weight. And the difference between me and, you know, your, your Taylor Atwood or your, your Pana and Yotis is that they must then get on stage or sorry, on the platform at, you know, the ability to go up to the 74, 83 kilo class respectively until they'd already been world champion for a while. So you can see this interplay in the real world. And if it didn't work this way, natural bodybuilders who lost muscle, you know, in the late stage of their career would be like, I'm going to just retire because it's going to take me 10 years to get back to my old stage weight.

1:32:38And we would not be able to see, you know, advanced level lifters go up a weight class and actually improve. So those, those examples are essentially checks of natural experiments on, on kind of the understanding that you presented. So I'd say, yeah, you're right again, buddy.

1:32:55Dr. Jordan Feigenbaum:I like that. I mean, that was my own experience. I mean, I started, I did my first meet, I believe it was either 09 or 2010, first powerlifting meet. I weighed in 179 for the 181 division. And I had to cut to get there because I I'm five foot, 10 and a half, not a tall person, but still for powerlifting, I was the tallest person in the 181 class and I had to diet down to get there. And I think my first total was 1300 and something pounds or whatever. And then that did, uh, got a little bit better the next meet, but it was one, then they switched to the 83 kilo class. So I had a little more wiggle room, 1350 or whatever.

1:33:33Dr. Jordan Feigenbaum:And then I, I remember I shit the bed at this meet. I like, I tried to, I was like, I'm just going to cut more because my body weight kept trending up a little bit um i think i cut try to cut down from like 195 or something to get down to like 183 that me yeah was bad for me and i was like i think i just need to go up a weight class as soon as i went up a weight class 15 50 16 something whatever i ended up at the top of 90 the 93 kilo class i totaled 1795 and i'm like okay that's great how do I get better and unfortunately I've never been willing to take my body weight up even further than that the only sort of proof of concept is that I've done a few fun meets where I did not cut down to make the 93 class or the 90 class depending on the federation and I just competed as a light 100 kilo lifter so I was like 95 96 and low and be my best total and it is because I think my muscle mass was going up and then if the further I restricted myself effectively did not allow for any muscle growth or at least not a substantial amount of muscle growth and so what people might be hearing this like oh so I just got to gain muscle to get stronger it's like well on some level that it's going to be your limiter what do you create force with well it is your muscle it has to be highly coordinated it has to you know in order to actually express that Jeremy is listening to this somewhere he's like it's not just about the muscle mass and we agree it has to be coordinated and everything else but yeah if you constrain yourself in this energy constraint not only will that some on some level constrain your training load to some extent but it's also going to constrain in this case the muscle mass and so what we've established here is this relationship of energy availability so you can have high energy availability because you have high amount of body fat and if you're that person probably don't need a surplus to maximize maximize muscle mass.

1:35:30Dr. Jordan Feigenbaum:On the other pole, you can have very low energy availability, perhaps bordering on relative energy deficiency in sport or leading to that. At that point, the energy constraint is such that you cannot really gain appreciable amounts of muscle mass, even if you're training your face off. So if you're a very, very lean power lifter, very, very lean, generally speaking, maintenance or a deficit, it's probably not the move to maximize muscle mass i think everybody listening is like yeah we already knew that but where i think it gets more interesting is like for the average we'll call a recreational recreationally trained person who's sitting at like for a guy 18 body fat and they're like okay what about me man should i just be on 100 calorie or 200 calorie surplus to ensure that i'm maximizing muscle mass or is it okay to sort of like, again, some days I'm a little lower, some days a little higher.

1:36:25Dr. Jordan Feigenbaum:On average, I'm kind of maintaining my body weight. I think that second category is probably where you should be mainly because you're at a lower risk of putting on unwanted body fat and energy is not the constraint. The constraints, really the training. And then once the training stops being the constraint, then it's genetics. And it's like, well, CRISPR is not yet widely available. So, so we go back to the training to see if that actually is modifiable. Does that, that square kind of with your understanding here? It does. And I think it also demonstrates how you sort of can't game the system, even when you are willing to do extreme things.

1:36:59Like you talked earlier about, well, maybe you could do more training to offset the use of protein and that it's coming from muscle. But then people forget, how do we calculate energy availability and the potential for REDS? It's literally taking into exercise expenditure activity into it. So by trying to actually offset low energy availability and training harder and more and increasing what is going to eventually show up as increased energy expenditure through the activity or increased energy expenditure from all the costs that Nikolaitis said of actually trying to build the muscle itself, because some of that's on the energy outside.

1:37:37thermic effect you know the actual cost of building muscle that's not a an inside that's an outside of that equation you're creating reds so you're accelerating reds by trying to offset the muscle loss from reds or that constraint and one of the symptoms of reds and one of the associated things is loss of lean mass sarcopenia osteopenia and actually experimentally poor muscle protein synthesis. So we actually know that by trying to offset it in a constrained system of energy and body fat, you're triggering your hypothalamus even more to go, oh, whoa, this, now you're moving more. God damn it. You know, now I need to pull more, more protein.

1:38:18So there's only so much you can do with trying to fix something that's not the constraint there. So I would totally agree. If you're talking about someone who's in that kind of mid range where that's not the constraint, then within reasonable ranges, you just don't have to worry about that. And to your point, again, we can use the real world. You probably have a more robust skeleton than me. In fact, I know you do. We met at EPC. We're actually a very similar height. We're a similar height, you and I, right? And I am not totaling. What's your best, like 1800 ish. Yeah. 1805.

1:38:55Dr. Jordan Feigenbaum:Yeah. Right. So, so, so my best, uh, if, if I was to take my like best case scenario, gym total, um, is like 1400, you know, that's very strong for non good power lifters. It's like 80th percentile, right? I think it's good. Yeah. It's good if you're, if you're not trying to be an elite level power lifter, but the, um, the reality is, is like another more extreme version is, you know, is also the same height as both of us is Mike T. and he's a 120 right so and he my my friend like i could fit my skeleton inside of him and you'd never know where i went you know and i've you know and he walks around at 120 and the heaviest i've ever been is lighter than his lightest he was in high school as a freshman that's just who he is yeah and there's a reason why he's you know totaled well uh into the 900 kilo and and he used to be in his heyday of you know one of the top level 120s right so there's an example there where if if he had tried to stay say at 105 he would be constrained just like if you were trying to stay at 93 it's a little bit constrained compared to like 100 but me because i'm the same height as you guys and i read body uh you know power lifting stuff remember back in the day when like the the shiko height weight class stuff was going around you know if you're six foot you're supposed to be a 120 and if you're any taller than that you should be a super right super yeah yeah yeah this is that data that's actually data derived but it's data derived from observing the top level lifters so it's saying if you are a top level lifter this should be your height weight ratio and i think that assumption doesn't work for me because i've tried to get to 105 jordan i couldn't get there i got to like 98 i hit a bench pr but my squat and deadlift were the same and then i had to cut down to 93 because i didn't want to compete as a 105 and the cut was so harsh that i passed out on my deadlifts so i totaled less right so yeah for me it just grows when i try to go up to all right so so i i think um i have personally found the the point at which trying to go up in weight class didn't benefit me because my natural structure, it looks muscular, but in terms of the actual lean mass that I carry for my height, it's a little below your typical strength athlete, bodybuilder, et cetera.

1:41:25You know, I'm a six foot guy who competes in the border between the middleweights and the light heavies. I look muscular, which is great for bodybuilding, but in terms of the actual structural tissue, when I diet down for a bodybuilding show, I can compete in the 83s. And a six foot guy in the 83 is what's called not an elite level power lifter. So trying to match the kind of height weight expectations of elite level power lifters is inaccurate. And I saw this coaching Bryce Lewis, who is a world champ. He's 5 '6", and he had one of these logarithmic increases in performance going from 93 to 105.

1:42:06you know so this stuff and he has probably a higher personal fat threshold that is still healthy and benefits his his uh that is like the constraint is maybe a bit lower than than mine for example i can walk around a little bit leaner so the interacting effects here are exactly that and i think the way to test it is that if you are reasonably active you have a healthy baseline diet that is consisting of sufficient protein intake, mostly unprocessed foods, a decent high fiber intake, and behaviorally, you're not kind of in the obesogenic loop that most people in Western society are, where just living life is actually a surplus.

1:42:46If you're living and you can have, be it maintenance, are you hungry regularly? Are you having experiencing food noise? are you having any kind of sleep disruption? Do you find that your libido is maybe not what it has been in the past if you're a male, for example? You're probably constrained a bit by either body fat or energy intake for that body fat level. But if you're not starving, you could eat. Your body fat is quote-unquote normal-ish or a little bit higher than it was in your natural state and, you know, like things are all good and you don't notice when you slip into a deficit or a surplus, it doesn't like immediately mean you get four hours of sleep in the wake up middle of night, then you probably don't need to worry about your energy intake because you're in a well regulated zone.

1:43:34You can easily have what's called quote unquote metabolic flexibility. You can tap into fat, you can tap into glycogen, you can onboard glucose, you can onboard triglycerides exogenously and supply all the energy needs from different places. Your body isn't coming in. The manager isn't going to the factory going, no, no, no, no, no. We are not putting anything more on that conveyor belt. We're only pulling from here or we're reversing that conveyor belt. I want those amino acids for energy. So I think in that state, it just sort of doesn't matter. Just don't do anything extreme. Don't be in a massive surplus or you'll gain body fat.

1:44:09Don't be in a massive deficit because then you will constrain muscle growth.

1:44:13Dr. Jordan Feigenbaum:that's uh yeah well said i think if conceptually people think about two separate intervention points a high one and a low one we're talking about body fat high and low body fat well if you're in this sort of unregulated zone between you probably don't have to worry about energy intake or micromanaging it now you may want to be leaner and so you can go you know by restricting calories and increasing activity, you can, um, go get closer to your lower end. If that aesthetically or perform it, whatever you want to do that, that's great. If, uh, you feel like, uh, again, any of those signs or symptoms that we'll call this energy perturbation, you may, uh, want to eat a little bit more.

1:44:55Dr. Jordan Feigenbaum:Um, you know, unfortunately we live in this society and we're in the fricking health and fitness space and people want me to be leaner than what I would probably be my strongest or most muscular, but you know, I am, uh, I, I receive pressure from the outside world, just like everybody else. So, you know, here we are stuck. Um, just a few, a few more questions and we'll, we'll wrap this up. The first one, which I think is probably the most important one, if we're saying that look, um, below 12 % body fat for a man above 20%, those are the poles in between. You can be at maintenance, you know, outside of that.

1:45:29Dr. Jordan Feigenbaum:If you're at the high end, you could probably be the deficit and be fine for maximizing muscle gain. If you're below that, You probably need a surplus in order to maximize muscle gain in the middle. You can be maintenance if you want. What would falsify this relationship? Because, you know, it almost it almost makes too good a sense. It makes me feel too good. It's really tied the room together. If you're a big Lebowski fan, what would falsify this sort of relationship? What would you have to see in the data or and or observationally to be like, dang, we messed up again? Yeah, so. I think that that's a great question and I've asked myself that many times is what would I need to observe that would tell me actually you always need to be in a surplus to get any kind of appreciate muscle gain and something happens when you tick down a maintenance or lower and it really messes things up I think what we would need to see would be like these non-linear relationships in these meta regressions that in some cases they didn't try to fit it, but we did see it.

1:46:33I would need to see Vargas, Melina replicated and them to actually ensure that they did have a maintenance group and that that maintenance group did way better than the rest. You know, so and I think it would also. I would need to see different things in practice to where, you know, the the the clients or the bodybuilders or my contemporaries or the power lifters would essentially be able to see much more steep increases in, in, in, in like totals as they went up weight classes. I think, um, another way to kind of disprove this is because, you know, if you're in a surplus to gain muscle and that is always what you should do, you eventually get to a point where you're just bigger and bigger and bigger and bigger and bigger, right.

1:47:22From muscle mass gains. but you don't see the same linear relationship in the supers. Right. And I think there's actually a really interesting thing is that the athletes who, the people who carry the most fat free mass on the planet are sumo wrestlers. Right. And I think there's two things going on there because it is different than say sarcopenic obesity, you know, in a sedentary, which is not the norm. It's, it's, it's relatively rare in a sedentary person who's very unhealthy and not exercising, who develops obesity, if they continually gain weight, they eventually get so heavy that they cannot be active and therefore they atrophy.

1:48:03But when you look at linemen, when you look at sumo wrestlers, and when you look at super heavyweights, because they actually did do a DEXA scan of Ray Williams, you can find that in the literature, which is pretty sweet. They have more lean mass than they could ever carry at a lower body fat because they're essentially replicating that environment we talked about of 1.5 g's all the time because they're active individual running around and this is kind of also why outside of sarcopenic obesity several voices in our space have currently been saying i'm not too concerned with lean mass losses when people are dieting and doing not maybe the best exercise protocol who would ever say that Because it's kind of, oh, who would, right?

1:48:47I listen to it on your guys' podcast.

1:48:50Dr. Jordan Feigenbaum:Yeah, I would say that. Because, like, the funny thing is we can look at the same data interpreted differently. When I talk about, like, a natural bodybuilder, they're doing everything they can to maintain muscle mass. And every little bit counts. So, them trying to offset the loss of maybe three or four kilograms of lean mass to two, massive difference in terms of placing on a bodybuilding show. No difference in terms of functionality. or life quality or any of this stuff, right? Except for lower life quality from not being as jacked and they hate themselves. But if we're talking about someone who does like a walking protocol and a half decent lifting protocol, and you're thinking, oh man, they could have maybe retained slightly more lean mass.

1:49:31Like they're not just losing muscle. And the muscle they're losing is maybe just because they don't weigh as much and their activities of daily living are just adjusting to what is necessary for moving a now 100 kilogram body versus being 140 kilograms.

1:49:49Dr. Jordan Feigenbaum:Right. So I think like unavoidable sort of loss of lean mass because now they're not getting that training load, which was their from life, basically. Exactly. And it is only when you put people with obesity on training protocols that provides a greater stimulus than what they were getting from living life as a heavier person and they're experiencing fast rates of weight loss, so they maybe are triggering their hypothalamus a little bit and they're seeing rapid decreases in body mass, if they're doing kind of a half-assed training protocol, nothing happens. But if you're seeing relatively slow rates of body weight loss and they're doing a decent training protocol and the deficit's not too large, well, guess what?

1:50:31Just like we already talked about, there's a meta-regression, which exactly proves my points here. Murphy would show that if you're in less than a 500 calorie deficit,

1:50:40Dr. Jordan Feigenbaum:it on average you're putting on lean tissue while losing mass so it it all still keeps supporting the same model jordan and i've thought through this a lot as you can tell i've thought through sarcopenic obesity sumo wrestlers anabolic steroids natural bodybuilders power lifters going to space animal models even weighting limbs of quails tying weights on chickens and rabbits and doing it for a month and seeing these rapid rates of growth that then plateau, but at much higher degrees of muscle mass before then they're sacrificed and thinking like, how much more did they feed these rabbits though?

1:51:20They probably weren't thinking, oh, this rabbit is going to get jacked. I need to give him like protein and the feed. You know what I'm saying? But it's not there. They're massive hypertrophy.

1:51:31Dr. Jordan Feigenbaum:Yeah. Yeah. We come to this similar point when it comes with the GLP-1 or incretin therapy, generally speaking, you talk about lean mass loss. because people are hyper-focused on lean mass. And Dr. Baraki and I have kind of come to the conclusion that we are less concerned with lean mass for its own sake, but more about its function. And we really wish people would just switch to more functional-based testing, like the fact that you see X amount of loss, X percentage of loss on DEXA scan, for example. Okay, glad you collected that. Thank you. You know, would have preferred MRI, for example. But a little DEXA is fine.

1:52:08Dr. Jordan Feigenbaum:let's get a strength, let's get a strength test. Even if it's something like a timed up and go or a stair power or something, or even grip strength, even though we don't really love grip strength. But we saw that in the semiline study. These people lost substantial amounts of their body weight, 15 plus percent on average of their body weight, did not do exercise. They all, over half met criteria for sarcopenic obesity prior to the start of the study, which reduced throughout this year long study at max semaglutide doses. and their grip strength improved. And it's like, okay, this is a non, you know, weight bearing limb.

1:52:46Dr. Jordan Feigenbaum:How did their muscle function improve, even if they lost lean mass? And it's like, well, some of that's due to getting the fat out of the muscle, probably, right? The other part is that they have less mass to actually move around. And so there's some sort of functional improvement there as well. So anyway, yeah, would would stick more in function for that particular case. But this has been um very very useful i think people are going to have more questions you guys just published this huge thing in mass on this very topic um i just had one more one more question and then i think we can you have you plug all your new book and and everything else where people can find this on mass we've i've talked on the last two episodes of the podcast about this idea of a personal fat threshold where people can store a certain amount of fat, primarily subcutaneous under the skin.

1:53:37Dr. Jordan Feigenbaum:And once they exceed that, that fat starts spilling over into places where it shouldn't be generally causing harm. It goes to the liver, it goes to the visceral adipose tissue, goes to the muscle around the heart, pancreas, et cetera. And so in those places, it matters not only that fat's there, but also what type of fat is there and what it's doing. Is it turning over? Is it static? Okay. People get that. Would you say that there's sort of a personal fat threshold on the low end as it, uh, sort of signals maybe energy availability. And maybe that is the, the crux of like, it's permissive almost for hypertrophy.

1:54:16Dr. Jordan Feigenbaum:Does that seem reasonable to you? It absolutely does. It comports with, um, what we understand of, of the data. Um, And it comports with what I see in practice as a coach. I think this is an example where, you know, I'm pulling from different lines of research and sometimes they don't talk to each other. Like the, if you look at all of the data, the underlying research that eventually led to the energy availability and red statements that came out Montjoy and the most recent ones in 2023, they haven't yet incorporated body fat percentage. And that is because, in my opinion, most of the time, there's a co-occurrence of people being in a deficit and seeing that cause the problem while they're getting too lean.

1:55:09And it is really rare and only kind of in weight class for good sport and bodybuilding where you can where you can try to tease out the difference between being too lean, but maybe being in maintenance or being in maintenance and that not being an issue like we talked about. So they're kind of looking at it through the lens of the etiology of low energy availability is not eating a sufficient amount for your activity expenditure. They're not looking at the metabolic adaptation literature. They're also not looking at the literature that is more broadly on body fat settling points. So it's not like Speakman is talking to Mount Joy is talking to libel, right?

1:55:51Dr. Jordan Feigenbaum:Is this a situation where you could have somebody who's like 25 % body fat, right? And now they go on a thousand calorie per day diet. And so massive deficit. Right. And so it's almost like an acute low energy availability state that is causing perhaps some of this sequelae that you would see generally in people who are very lean and who are also not eating enough for their activities. Is that kind of where you're going with this? I think so. And I think there's probably limits to how much that can have an impact because there are great examples of extremely low calorie diets. where obesity researchers and clinicians were exploring the issues they ran into and going, oh, maybe we should at least give them 10 grams of fat so they don't have, you know, like, you know, failures of their bile ducts, right?

1:56:39Or, hey, this dude, you know, fasted for a year completely and I wanted to at least give them, you know, a micronutrient. And I think it's also why we see showing up in the most recent red statement and why we get some pushback from, say certain researchers like Arita, it's like, hey, not everything is a negative adaptation to low energy availability. There's functional and non-functional. And you can bring in the, looking at the subsistence farmers and hunter gatherers, like they're doing an okay enough to pass on their genes. They're getting not great sleep. You know, they're basically running around as the exercised hypogonadal male, but it's still enough to pass on their genes, procreate and continue the tribe, right?

1:57:25They go in and out of states of low energy availability, and it's a problem to the degree it's a problem, but they are probably used to living their life at 9 % body fat and being in non-debilitative low energy availability all the time. And it's okay to be a five foot five, you know, not fully like, like maybe if they had more food, the whole tribe would be five, 10 kind of scenario, right? You know, and that's what we see in societies where they move into more modern or food available situations, see it in history. And so that is exactly what I'm getting at. And it may be that... That 1 ,000 calorie deficit is a problem for that person, not at 35 % body fat, but becomes it at 25 % body fat when they get there.

1:58:12And that could be lower or higher for two different people. And also, there probably are some interactions of sex. I think you can induce a state of perturbed LH pulsatility. So luteinizing hormone pulsatility is kind of the early warning system, not clinically, but in terms of research that indicates this person is probably going to experience oligomenorrhea or amenorrhea. And you can do that by putting even women with obesity on a starvation diet. So that specific system of saying, hey, I'm going to enable you to get pregnant and potentially grow a child inside of you and then need to breastfeed it for several months.

1:58:58I'm not going to do that right now when there's no food around. Because, again, Jordan, you and I probably wouldn't be here to talk about it if that was one of the adaptations that didn't get filtered out. Some tribe that, you know, you're starving and it's like, you know, let's grow a baby. They're like, oh, man, we're all dead. So I think. Right. Yeah. It doesn't go on. Yeah.

1:59:14Dr. Jordan Feigenbaum:No more. No more finishes. Yeah. Exactly. The last question I have for you, then you plug away. What are we most likely going to be wrong about when we look at this five years from now? You and I, like if we look back on this podcast, yeah, I would say probably anytime I get out into speculation land, there's many models that can fit the observed data that we have. But it doesn't mean they're not wrong. It just means they are sufficient to explain it. A great example is like Newtonian physics is not actually the way physics works. Like you have to bring in, you know, our understanding that Einstein brought in.

1:59:58But it didn't matter until we didn't just want to, you know, escape the atmosphere. Like we wanted to make GPS satellites and we wanted to land on another planet. And like, oh, shoot, relativity matters now, right? So I think I don't know. I think muscle memory. We have much more to learn about why you stop growing. We have much more to learn about. And I think also I would say the, the magnitude of growth that one can achieve. Like, for example, I kind of presented this is if you could somehow do a greater stimulus, then you would have more lean mass. I think there probably are some like chassis limits.

2:00:36Like if you and I went and said, Hey, I want to go live on a, like a 4g planet. we would probably die in five years at like at best right like we just can't sustain that our heart would fail but if we went to go live on a 1.3 g planet maybe you and i would be jacked um you know and just and be happy but tired all the time unless ryan reynolds saved us yeah that's true yeah perfect example so like i think there there are limits to this and and describing them directionally is inherently wrong. But there is like, we have millions of years of adaptation on a, on planet earth with exposure to, to, to mechanical tension.

2:01:20And there is going to be a limit to, to what we, you can do. So I would be very curious. I think what I, maybe I don't understand fully is the, uh, is it true that anabolic steroids are basically just lifting up you're kind of doing that second puberty. And I think some of the drugs that are being developed are going to help us understand this, like a myostatin inhibitor, because there's many different ways that you can reduce use of muscle for, you know, basically reduce catabolism so that you're in a net anabolic state or induce anabolism so that you get past that catabolic limiter. And then you can also manipulate where those constraints lie with drugs.

2:02:03Yeah, yeah. You know, like if you give somebody clinbuterol, for example, which is not an explicit anabolic agent, it essentially enables you to tap into fat stores at much lower body fats and it, you know, with much more efficiency where if you went into a larger deficit, you'd start pulling from lean mass and also is an anti-catabolic for muscles. So it's like a body recomp agent and it follows a pathway that you probably wouldn't think about. So I think as we explore drugs, it'll actually help us understand more about the underlying physiology. So I think maybe the mechanisms by this might change.

2:02:43But I think I'm reasonably comfortable saying like the way I've described it is sufficiently accurate that none of the observations we have clearly break it, you know, in certain terms of a model in our minds. Yeah. Yeah.

2:02:58Dr. Jordan Feigenbaum:Yeah. we may get better technology to sort of better predict time course or, or response or like, you know, link stimuli to outcome like better. But I do, I am in agreement with you that where my interest lies are identifying new constraints. And so if we have no more anabolic constraint and catabolic constraint, well, now is it for muscle? Is it for the blood supply? Is it for the bone? Is it for some, you know, something else, some other system that has never been constrained up until now in the superhuman RoboCop AI era? Watch this space. We'll probably still be doing this five, five or six years from now.

2:03:39Dr. Jordan Feigenbaum:So we'll find out. Okay. So the practical version, there are three buckets and the numbers are mostly for men. So add roughly 8 % if you're a woman. Above about 20 % body fat, energy isn't your constraint for building muscle. You can sit in a modest deficit, under 400 calories per day. As long as you train hard and you get your protein in, you'll build the maximum amount of muscle while you lose fat. If you were to eat in a surplus, that's mostly going to put on additional fat. Below about 12 % body fat, that seems to change, and a small surplus starts earning its place there. At that point, your body has stopped treating its fat stores as something it's willing to spend, and so you need extra energy coming in from the diet.

2:04:20Dr. Jordan Feigenbaum:in between those two points which is where most people are it mostly doesn't matter don't run a big deficit but you also don't need to run a big surplus you mostly spend your attention on the training load and when it comes to protein the meta regression that dr helms worked on gives you a number if you're over 20 body fat about 1.6 grams of protein per kilogram body weight gets it done when you're under 12 especially if you're not in a surplus that number tends to climb probably closer to 2.5 grams of protein per kilogram of body weight. The leaner you get, the more your body starts eyeing your muscle as fuel, and you need some extra dietary protein to make sure it doesn't take it.

2:04:59Dr. Jordan Feigenbaum:Dr. Eric Helms, tell everybody where they can find you about your new book, and I will link all that in the show notes. Absolutely. We finished the third edition of the Muscle and Strength Pyramids end of 2025, so you can find those on Amazon if you want a physical copy, or if you're happy to get the PDF, check out muscleandstrengthpyramids.com. And then if you're interested in nerding out to this degree and reading how I've written extensively about how body recomposition works and the interacting effect of energy intake, energy availability, as well as training status, then check out massresearchreview.com.

2:05:32That is where we have a monthly basis of looking at stuff like this. I hold down the muscle nerd corner, but we've also got Lauren Colenzo Semple, Dr. Eric Trexler, sorry, Dr. Lauren Colenzo Semple, Dr. Eric Trexler, and Dr. Mike Zerdos were all a part of it. So definitely check those out. And if you really want to dig into the primary research or read some of the stuff that I've done in this space, I'm also an active researcher and you can find me on the Google machine, Google Scholar. I'm the current director of the Sports Research Institute New Zealand. I've been doing that and we're trying to do more research specifically on this topic because I'm interested in it and now I know how funding works.

2:06:14So, yeah, that works.

2:06:15Dr. Jordan Feigenbaum:Yeah. Yeah. And you're, and fortunately outside of the United States where you can still get funding, that'll be correct. And that'll be his fourth appearance on the barbell medicine podcast. We talk about that. Uh, thanks everybody for listening before you guys go anywhere, please leave us a five-star rating and a review really helps drive traffic to our podcast.

2:06:35Dr. Jordan Feigenbaum:So we I'm Dr. Jordan Feigenbaum. We'll catch you next week and every week right here on the Parval Medicine Podcast.

2:07:09For more information,

2:07:18visit www.fema.org