Leah:
Hello and welcome to the Ideal Nutrition Podcast. I’m Leah Higl and I’m here with my co-host Aidan Muir. And today’s episode, we will be discussing the golden rule for protein when you want to gain muscle mass. You may have come across this, but it is the 1.6 to 2.2 grams per kilo body weight per day reference range. So we are going to unpack this a bit and discuss whether it would be beneficial to actually go higher than this kind of gold standard reference range.
For us, that protein reference range comes from two main large reviews that have been considered the gold standard on this topic for quite some time now. One from Morton and colleagues and another from Brad Schoenfeld and Alan Aragon. So big names in the space. These numbers are not intended to be perfect and adjustments do need to be made based on the situation.
So if someone is leaner, they’re going to require more protein per kilo of body weight than someone who has a higher body fat percentage. So it’s not a perfect system, but it’s been a nice little like reference for us to be like, okay, if we kind of get within here and then we adjust according to the particular person that we’re thinking about, then it’s probably pretty on the money in regards to optimising muscle mass. And then we also have the fact that protein needs are also higher in a calorie deficit. So that is another thing to consider.
But focusing on that 1.6 to 2.2 range, this podcast is partly inspired by an article from Greg Knuckles, which has challenged some of the assumptions that have been made based on a different statistical analysis and also an updated review of the research that he’s kind of popped together. So we’ve added that in the show notes. I tried to read it thoroughly and I had that brain thing where it’s like, my brain just kept like, moving away from it. It’s a pretty dry read. Aidan has gone through it really thoroughly and put together the notes for our podcast today. So our goal for today is realistically taking that article and summarising it in a way that is more simple, easy to understand, and hopefully a little less dry. We’ll do our best.
Aidan:
Yeah, that’s the goal. There might be moments where it gets a tiny bit complex, but like when you read through, there was some like, yeah, there’s some deep stuff in there but we also have a very practical finding at the end as well. So we’re going to talk through a little bit about statistics with the original article. So not too deep here, but like the original article largely came to the conclusion that 1.62 grams per kilogram appeared to be the point at which muscle growth did not increase beyond. And then the 2.2 grams per kilogram number is just kind of added on top to account for our outliers and technically it’s based on a confidence interval.
I just don’t want to go too deep into the statistics there, but what kind of like definitely added a bit of like credence to this is that both of those reviews by different people came to the same 1.6 to 2.2 kind of range. Now, the first criticism that Greg kind of pointed to was that the 2.2 number is like pretty arbitrary. was just like, they’ve just picked a number with a confidence interval. He made the very valid point is like, if you’re using confidence intervals, technically the range that came out from the study was 1.03, so 1.0 to 2.2.
And like, obviously we can see that that’s a pretty useless range. It’s like, that doesn’t give us anything. So it’s like, if we’re to use a statistical technique like that to like figure out how much protein we need, like it just falls apart when you look at it bit closer. In that original paper as well, like he pointed out that there was a big lack of research that actually looked beyond 2.2, which is super relevant because there is a lot of studies that actually do look beyond that. And there’s a lot of people in the real world who are eating more than that.
And he made another very valid point that even within that study, if you looked at some of the graphs in there, when you go beyond 1.6, it led to more muscle growth. And he pointed out that like, that’s just not something that has really been spoken about in the community and stuff like that. People just kind of like focused on the number, not really the fact that we look at that. And to really drive that point home, he’s like, in all five studies where they consume more than 1.6 grams per kilo protein, they gained more muscle.
So the interpretation has been chucked out there as though like 1.6 is like, there’s no need to go beyond that unless you’re in one of these outlier cases. But in all of the studies that were included in there, technically people gain more muscle if they want a bit higher.
Leah:
So this is where it might get a little bit dry for a bit, but bear with me. We’re just gonna briefly touch on difficulties interpreting the research and kind of what it means in this particular space. So trying to keep things simple, Greg also highlighted in his article some huge things that make this research particularly hard to interpret perfectly.
For the study to be relevant, it had to compare higher versus lower intakes of protein, especially because people’s training will be different in different studies. A good example is if you got a group of experienced lifters to eat high protein but do a low volume of training, they would obviously get worse results in a study looking at new lifters eating low protein but training hard. That wouldn’t be a fair reflection, it would be hard for us to interpret in this particular context.
Aidan:
And the point of that is it stops you from doing something that would be so helpful here, which is like, we have a ton of research looking at this. Could we not just take a step back and analyse just more broadly looking at each individual size and being like, all these studies use really high protein, all these studies use really low protein, how much muscle do people gain?
That would be a lot easier. It just falls apart being like, well, if they have anything different, like slightly different training or whatever, it would just destroy our way of measuring this. So it limits it significantly what we can actually look at to answer this question.
Leah:
It’s really hard to compare because there are so many variables that impact muscle growth outside of protein intake. Even people’s historical intake of protein could matter a bit too. So for example, if people ate high protein prior to the study and then they dropped their intake to follow the study guidelines, it could influence the outcomes. Another aspect is the variable of lifting duration. So this research looked at both experienced and inexperienced lifters. What if one group needs more protein than the other, but they’re all mixed in together for this analysis. So it becomes incredibly hard to separate.
And finally, we have self-reported data kind of sucks, which is a great note. Obviously when there is self-reporting, it’s never, it’s never going to be perfect. We can’t control what people do. They’re just reporting and that’s based on people’s memory. And that can influence the outcomes of a lot of studies quite significantly. So it’s something to kind of throw in there as well. So I think just generally highlighting that this is a really hard area for us to have perfect research to interpret in the perfect way.
Aidan:
That’s actually one of the hardest things I’ve found about being in the evidence-based community. I want to do a combination of a few things. One, I want to look at stuff and form my own opinions. And I’ve been doing this for a long time, so I feel like I’m relatively well equipped. But I’d like to think I’m humble enough to believe that I don’t know everything and that other people will spot stuff that I miss. So I look at like what a lot of other people say and I’m like, can I learn from them?
And that self-reported data kind of sucking thing is super relevant because I do see people making strong claims based on research. And then like you read the paper and you’re like, they didn’t even do it. For example, I’ve spoken about this on a podcast, like the 4.4 grams per kilogram, like protein study. It’s like, it says that, but like, that’s not what they did. Like they had a little bit less than that. But then when you see like people write content, they would just use the 4.4 number. It’s like, they did this, this is what happened. That’s not actually like, so self-reported data does have flaws.
Okay, going further, so the Morton article is from 2018. So that was like the more recent review. And I think the Brad Sheinfeld one and Alan Aragon was also 2018. So slightly newer research was included in this kind of article. So a 2020 review had a few differences. So was a tiny bit more recent, but it also separated lifters and non lifters, which is pretty relevant. They also had a much broader range of studies included. They even allowed weight loss studies to be included which raises the very obvious question of wouldn’t that influence stuff because we know protein needs a higher in a deficit.
So going through it, they also had a chart where you could look at muscle growth and they found an increase in muscle growth all the way up to three grams per kilogram, way higher than the top end of that like 1.6 to 2.2 range. But there are a few main caveats. So one is that there also isn’t much research beyond that intake. So it’s like, how do we know that?
Going beyond three isn’t like I know I mentioned a 4.41 but like that’s like rare. That’s that’s super rare. So just because it stopped there in that review, that doesn’t actually mean it actually stops at three grams per kilo. There are very clearly diminishing returns. It’s actually one of the key points I want to get to with this podcast. Once the chart hit about 1.6 grams per kilo, there was an increase in muscle per gram of protein progressively, but it became like became less and less. That’s going to be a thing we’re going to talk about that a bit more in depth.
And as mentioned, being a deficit could skew this as well. Greg pointed to the fact that only 12.5% of the included studies were weight loss focused. So if it was skewed, it’s not a major factor. I still do think it’s relevant putting that in because we do tend to see when people are on a deficit, higher protein matters significantly more, which could change the top end of that chart a little bit in my opinion.
Leah:
Talking a little bit about the newest research in this space. So the most recent meta analysis on this topic was in 2022. It was similar to the Morton one, just with updated newer research. And basically it came to the same logic of this diminishing returns aspect. So if there is a cutoff, the charts indicate that there were still increases in muscle growth up to 2.3 to 2.4 grams of protein per kilo body weight per day.
Aidan:
So now let’s talk about interpretation. So the first interpretation is that needs clearly are slightly higher than 1.6 to 2.2 kilo range. If you want to maximise things. A solid simple target is aiming for two grams per kilo. And then scaling that based on how lean you are. For example, if you’ve got a very high body fat percentage, you probably won’t need that much. If you go a bit lower, if you are super, super lean going a little bit higher, makes sense. And then this is coming from the article, a better safe than sorry approach proposed on top of that was a 2.4. Like 2.4 is the equivalent of somebody previously aiming for 2.2. So it’s like, it’s very tiny difference.
And then huge emphasis on the fact that 1.2 to 1.5 gets you almost as much muscle growth. People can still make progress at that level really well. Going higher is just if you want to maximise things. And I have two angles on this, so like I’ve almost always been in the camp of just like if it’s easy to eat more protein for you and you’re trying to maximise things, it makes sense to just do that. Like that’s pretty simple.
But there are many people who are trying to gain a bit of muscle, who do not care about like absolutely maximising things. And they could save a lot of money and also a bit of effort. They can be more flexible with food and all of these kinds of things by going a little bit lower. So I wouldn’t want them to hear about this being like, damn, I’ve got to get like 2.4 grams plus protein. And then a little final note that I was going to add on that is I did actually find it a bit interesting that like the better safe and sorry approach proposed being 2.4 when he did also talk about like the charts going up to 3.0 and it’s like, well, why wouldn’t the better safe and sorry be like 3 or 3.3?
Like, and it really depends. Like you can go deep on that and think about it in relation to like, if somebody’s like really into bodybuilding and stuff like that, and this is all they care about and they’re really lean, it’s like, well, maybe, maybe you go like three plus and anecdotally, if we look at all the bodybuilders who step on stage and we measure their protein intake, almost all of them are doing that anyway.
Leah:
Yeah, it’s just something that, I mean, it’s been happening for a while, all right? Like when I talk to bodybuilders, they’re like, yeah, I’m on like this crazy amount of protein. I’m like, yeah, it seems like the general cultural shift that happened a while ago. And it aligns with, with kind of what we’re seeing now. Overall, though, this hasn’t shifted my perspective all that much. I think it makes sense to shift our messaging slightly. I mean, we’ve both used the 1.6 to 2.2 reference range a fair bit, just in a bid for simplicity. Our job as dieticians is to interpret the research and the guidelines like this and convert it into simple and practical advice for our clients.
That’s the whole, that’s our entire job. So that’s all what we try to do. But thinking through it deeper, saying a simple number like just two grams per kilo body weight per day, arguably works even better because then you can just personalise from there. So personally, I kind of shifted this to this approach a little while ago when I’m like talking to clients one-on-one and then seeing this research and other people in the space talking about it in this way, I’m like, oh, it just confirms also what I had already thought and kind of where my mindset had shifted.
And then obviously with the individualisation, we want to be scaling based on leanness. think the better safe than sorry approach is great in combination with kind of that scaling and individualisation. Although I also like to consider the, what I call the return on investment and things like my time, money and effort. So for both me, for my clients in regards to what is actually worthwhile doing.
Like is it worthwhile adding 20% more complexity to your nutrition or spending X amount of money or whatever the case may be for one to 2% extra gains. Some people it’ll be totally worth it for others not so much. So I think it’s super relevant to that point of diminishing returns concept. Ideally we maximise protein intake as much as possible for muscle growth whilst factoring in these other things and whether or not it’s worth increasing past a certain point.
Aidan:
Yeah, and when we were speaking off air, we were thinking, we talking about how it’s like, we thought this quite some time, but then with the messaging thing, I find it interesting just reflecting being like, well, why did I ever use that range if I believe slightly higher made sense and stuff like that? And one of the biggest things to me is if you do say something that’s different to what the majority of the evidence-based community are saying or anything like that, like, you have to back it up. you have to, if somebody questions like, say, say I just use a range of like 1.8 to 2.4 and somebody’s like, why saying 2.4 instead of 2.2 or like whatever. I have to give like a really solid analysis. I’m not going to do an article like Greg did where I’m not going to do like something like that. So like, I want to be accurate.
I want to be simple and everything like that. And another angle I’m going to take there is like, I’m going to use an example of Ashwagandha. I had a client many, many years ago, basically say, can I take this supplement? And it wasn’t asking, should I? It was like, can I take this supplement? I want to. And I started looking at research on it. Like every study I was seeing was positive. Like there’s like questions and like, I know I’ve made content about this, but like there’s like a few reasons for hesitation and stuff like that. But all of the studies looking at reducing stress had positive findings. Anything that measured body composition, every study found improvements in body composition, improvements in sleep, all of these things. So there could be risks, there could be downsides, but like the research is pretty promising.
I didn’t create content on that topic for a year after I started like learning about it. And then like I made like one piece of content, but I was like, I’m not gonna, I’m not gonna talk about this much. And I saw a few other evidenced based creators talking about it. And it comes back to that perspective of like, like I try to learn as much as I can, but I also don’t want to just like have a hot take in case I’m missing something, in case I’m missing something. And like when I see other people in the space speaking about the same thing and similar conclusions, whatever, so much easier to talk about it. Yeah, I don’t know. That’s how I think about it.
Leah:
Yeah, I think that’s a good way to look at it. But this has been episode 193 of the Ideal Nutrition Podcast. If you haven’t yet left a rating or review, it would be always greatly appreciated for you to do so. But otherwise, thanks for tuning in.