Podcast Episode 40 Transcript – What is the Ideal Calorie Surplus Size for Muscle Gain

Leah Higl

Welcome to the Ideal Nutrition podcast. I am Leah Higl and I’m here with my co-host, Aidan Muir and our topic of the day is what is a good calorie surplus size for muscle gain?

So it’s definitely possible to gain muscle without a calorie surplus, particularly under circumstances where somebody [00:00:30] is newer to training, maybe has really good genetics, their recovery is on point, they’ve got a great training program. All these things kind of falling into place for them to be able to do that. But we know the way to optimize muscle building and muscle growth is absolutely through a calorie surplus and so the reason why a small calorie surplus is actually beneficial is because building muscle is a very energy intensive process. So it’s super energy intensive, so if you don’t have any extra calories [00:01:00] that aren’t already being used up through kind of normal bodily processes and your daily activity, what are you actually going to use to build that muscle? You don’t really have anything left.

So at the end of the day, calorie surplus is 100% the way to go if you’re wanting to optimize muscle building.

Aidan Muir

Yeah. So then knowing that that’s the way to go to optimize muscle building, the next question is, obviously, how large should it be? What’s the downside of going too large and the downside of going too small?

Too [00:01:30] small is easy. You just gain muscle slower than you ideally would be able to, so that’s obvious. Too large is also obvious in a way in that we know muscle building is a slow process and if you’re in a large calorie surplus, you’re gaining weight quickly. If muscle building is a slow process and you’re gaining weight quickly, and it’s not all muscle, you’re gaining a lot of body fat basically.

And now in amongst that nuance, we’re trying to find out what is the ideal kind of calorie surplus [00:02:00] size based on that way of thinking and it’s typically going to be this nice sweet spot where you’re gaining muscle relatively efficiently, and you’re minimizing body fat gain. If you gained no body fat, you probably could have done it a little bit quicker and gained muscle a little bit quicker. Even if you don’t necessarily care about gaining body fat, it’s arguably still inefficient to make it too large, because otherwise you might just have to either stop bulking, massing, whatever you’d want [00:02:30] to call it, you’d have to stop that calorie surplus phase sooner, or you’d have to start cutting sooner and you’d just spend less time in a calorie surplus, which we know is obviously the way to optimize muscle growth.

So on this topic, a study I often talk about is a study was based on college athletes and they got one group to go into a specified 500 calorie surplus and the other group they just told to eat ad libitum, as much as they wanted to, but try and eat in a surplus basically. And the [00:03:00] group in the 500 calorie surplus gained about just over double the body weight of what the ad libitum group did. They gained a tiny bit more lean mass, but they gained so much more body fat.

And these were athletes, so they were college athletes. They weren’t exactly following bodybuilding style programs, but they were in an off season trying to gain muscle mass and that therefore tells you that for somebody who’s decently well trained and has their life set up for this, they’re probably getting good sleep, their stress [00:03:30] is decent. They’re college athletes, they’re trying to do the best they can for this purpose. They still gain heaps of body fat in a 500 calorie surplus. So once you’re relatively well trained, even a 500 calorie surplus is probably too big.

Leah Higl

I feel like it’s also where a lot of people start though. People are like, “Oh yeah, 500 calorie deficit is kind of the go to.” So a 500 calorie surplus is also kind of people’s go to.

But unless you’re really new to training or have a low level of muscle mass already, it’s probably too much for most people, [00:04:00] I’d say.

Aidan Muir

Yeah, I’d agree because based on some pretty poor calculations, I’ll explain why these calculations are poor later, or we will explain. I’m not sure which one of us is going to explain it, but we’re going to explain why it’s pretty poor later. But theoretically, a 500 calorie surplus, if it all went 100% to being stored as, say, body fat, it would be 25 kilos weight gain per year if you did it over the entire year and your energy expansion didn’t change. And obviously we know your energy expansion does change, there’s a lot of things that go on, [00:04:30] but it’s kind of like, “Well, we know we can’t easily gain anywhere near 25 kilos of muscle.” It’s safe to say that it’s likely to do that.

But similarly to you, I hear lot of people talking about 500 calorie surplus is a good starting point and that was one of my intros. Bodybuilding.com, they talked about a 500 calorie surplus being the gold standard and I would agree it’s actually probably a gold standard for people who are pretty new to lifting weights and are really focused on lifting weights and trying to set their life up to optimize muscle gain. [00:05:00] But once you pass that initial stage, it’s probably a bit too quick.

Leah Higl

Yeah. Moving on to kind of that energy expenditure part of it, I just want to add a little caveat around that. So we know that in a calorie surplus, there is probably going to be increases in most people’s energy expenditure. So this does happen to a different degree in different people, but when your body has access to more energy, it’s likely to burn more calories through things like the thermic effect of food.

So if you’re eating [00:05:30] more, you’re going to be burning more calories through just digesting food and potentially there’s increases in planned and incidental activities. So if you’re just generally more energetic, because you’re having more calories come in, you might be working harder in training, training more often, taking the stairs, doing all those little things that you have more energy to do. There may also be an increase in your basal metabolic rate due to metabolic adaption.

Another thing that we have talked [00:06:00] about on this podcast a few times and we know if you’re in a calorie deficit, your BMR tends to decrease, vice versa when you’re in a surplus. Your BMR, your basal metabolic rate metabolism, will increase to kind of offset some of that calorie surplus and that has a lot of variability person to person. And then you’ve also got kind of your changes in body composition and the calories that are burnt through producing more muscle mass. So I’d say there’s definitely [00:06:30] more calories burnt producing muscle mass than there is producing body fat, so that’s something to be accounted for as well. So generally your energy expenditure is going to increase to offset some of that surplus. So yeah, just a little thing to kind of add in there.

Aidan Muir

Yeah, for sure. And that does make it interesting because those things are pretty variable and sometimes when I say things like, “Oh yeah, 500 calorie surplus is likely too big.” What if you happen to be a hyper responder in terms of changes in your energy expenditure? [00:07:00] Maybe 500 calorie surplus isn’t too big of a deal, hey? Maybe it works out to be a smaller surplus in practice if you think about it [crosstalk 00:07:08].

Leah Higl

Yeah. I guess the theoretical surplus is going to be different to the practical surplus and I’ve definitely had those high responders where I’ve given them what I thought was a pretty decent surplus and then they had some, yeah, initial weight gain and then it just petered out and I was like, “Oh, damn, I’m going to have to give this person more food because they just ended up burning more energy.”

Aidan Muir

Exactly, yeah. [00:07:30] Yeah and that is also why I do reference that study before where it’s like, “Hey, in that study, the actual theoretical surplus they gain heaps of body fat on 500.” But there are people outside of that, obviously. And digging really deep on this topic because it’s like, “Hey, it’d be cool to kind of measure this to a certain degree.” There is one study where they overfed participants by 1000 calories per day, six days of the week for a 100 day period to see what actually happened to their changes in energy expenditure and how that actually affected their weight gain and stuff like that. [00:08:00] And over the course of this 100 day period, the range of change in weight gain was 4.3 kilos gained at the lowest, all the way through to 13.3 kilos gained at the highest.

Leah Higl

Such a crazy range.

Aidan Muir

Yeah. You’d assume that most people would respond relatively similarly in terms of weight gain based on the theoretical calorie surplus, but this is very individual. And a lot of people look at this and try and be like, “Oh no, the calories in calories out model is broken.” But it’s like, “No, this is [00:08:30] factored in. The calories out portion changes based on the calories in and that’s an individual thing as well.”

So the next study that I’m going to touch on is… I don’t think it’s great podcast content, but it’s kind of if somebody’s interested in looking into this topic a lot, probably the peak study that’s really worth reading is there’s a study titled Is an Energy Surplus Required to Maximize Skeletal Muscle Hypertrophy Associated With Resistance Training? And it’s got a lot of heavy hitters, like Gary Slater, Eric Helms, and a few other [00:09:00] people on there. And from my perspective, it was a funny title. I don’t have it in front of me, but I think it came out in 2019 or something like that. I’m like, “2019. We know it is required to maximize muscle hypertrophy. We don’t need a study titled that to tell us that.”

But where the actual study was really, really interesting was it was really trying to pinpoint actual numbers of the energy costs associated with building muscle, explaining the changes in NEAT and they call it non-exercise activity thermogenesis, thermic factor food, all of those kind of things. [00:09:30] There’s very few practical takeaways in that study. It’s very theoretical. It’s trying to really science this kind of topic and make it more complex than it needs to be. I’ve said it before. I don’t exactly view myself as a pro scientist but I read that and I’m like, “I don’t know, I just want to lift some weights and eat some food. It’s not this hard.”

But their recommendation based on going through all the science was to start with a 300 to 500 calorie per day surplus, monitor body composition from there and make adjustments over time. [00:10:00] If going for that 300, 500 calorie range, you gained body fat too quickly, you just decrease the surplus. Once again, it’s not that hard. You just decrease the surplus. If you weren’t gaining at all, or you were gaining very slowly, you just add more calories. Where you start doesn’t really matter. It’s not that important. It’s how you adjust things over time so that you’re consistently gaining muscle at a rate that you want to be doing ideally while limiting body fat gains.

Leah Higl

Yeah. [00:10:30] Generally when I’m trying to work this out, I don’t really put too much thought into what’s the size of the surplus because I know obviously it’s going to practically change as energy increases. So I think about what’s the rate I want this person to gain muscle. I’ll pick a number that I think theoretically sounds pretty good and then we’ll adjust based on what actually happens to their weight over time rather than worrying about, “Oh they’re on a specific 300 calorie surplus.”

Leah Higl

I think people put too much [00:11:00] of an emphasis on those kind of numbers.

Aidan Muir

Yeah, exactly. I completely agree and that’s how I work it too. Particularly once the numbers start getting smaller as well, because if I’ve got a 500 calorie surplus, it’s probably too big. What happens if you’re at the point where you’re forever chasing that last one to two kilos of muscles? You’ve got to go quite slow. Yeah, we’ll actually talk about that, so practical takeaways, I guess in terms of how we view it. The way I view it is for beginners, [00:11:30] probably one to two kilos per month, which theoretically is a 250 to 500 calorie surplus before factoring in these changes in energy expenditure. Intermediates, 0.5 to one kilo per month and then advance when you’re forever chasing that tiny amount of muscle growth. You’re looking at 0.2 to 0.5 kilos per month.

I’ve categorized it like that, but that’s under the assumption that you don’t get injured or you’re really focusing everything on [00:12:00] trying to gain muscle. You’re trying to sleep or you’re trying to minimize stress, you’re eating good protein, you’re on a good training program and all those kind of things. And the further away from that you get the more you shift it. If you were somebody who was technically a beginner but you only lift weights twice per week, you live a stressful life and you don’t get much sleep, I’d probably go towards the intermediate [crosstalk 00:12:18].

Leah Higl

You don’t want to be gaining two kilos a month.

Aidan Muir

Yeah, exactly. It’s not going to end well. So shifting between those… But if we’re talking about the mathematics on it being like, “Okay, 0.2 to 0.5 kilos [00:12:30] per month, half a kilo per month.” We’re looking at technically a theoretical 50 to 125 calorie surplus. We can’t predict our energy expenditure that accurately to the point that we’re down to that level of specificity. That’s why it makes sense to focus on the actual outcome in terms of weight gain.

Leah Higl

Yeah and just adjust around what is actually happening on the scales rather than worrying too much about the calories coming in and that specific number. The people that I work with tend [00:13:00] to sit around that half a kilo per month is good for them because usually they’re either an intermediate athlete or they’re a beginner athlete, well somewhat beginner, but they’re not training that much and they’re not recovering the best they can. So yeah, I find that that middle ground is good for most people.

Aidan Muir

Yeah. Yeah, for sure. And the other thing, it’s a complicated topic, but a lot of people will come to me and be like, “Oh, I don’t care about scale weight. I only care about how I look.” And that’s true, that’s what we’re working towards. Look, [00:13:30] performance, whatever you want to call it. That’s what we’re working towards. But the scale weight, to a certain degree, once you average it out and everything like that, you’re not looking day to day, you’re looking at the average over weeks months or whatever, can inform other stuff because, say, we care about body composition. If you gain five kilos in a month, for example, because you don’t care about the scale or whatever, we know that’s not going to be muscle. It’s enough to inform. It’s one piece of the puzzle in terms of gathering information basically.

Leah Higl 

And usually people don’t want to be gaining too much body fat, so it’s a good data point to just track and adjust around.

Aidan Muir

[00:14:00] Yeah, exactly. And you can also, if you do measure body composition in some way, shape or form, you can then use that for future. If somebody gains 10 kilos of mass over a six month period and they measure their body composition and they gain more body fat than they wanted, next time they might be like, “Okay, next time I do a massing phase, I’ll only gain five kilos over a six month period.”

Leah Higl

That’s why I love pre and post DEXA scans. They can tell you so much about what percentage of it was body fat gain and muscle mass gain and that can be really good to plan your own individual [00:14:30] bulking periods.

This has been episode 40 of the Ideal Nutrition podcast. Thank you for tuning in.