Sept. 2, 2021

"High Protein Diets: In Context" with Professor Kevin Tipton

Episode 164 of the Institute of Performance Nutrition's "We Do Science" podcast! In this episode, I (Laurent Bannock) discuss "High Protein Diets: In Context" with Professor Kevin Tipton (The Institute of Performance Nutrition, UK).

Discussion Topics Include:

  • Overview of High Protein Nutrition Research
  • Science communication and translational issues: terms such as "hi / low protein"
  • Potential contexts for high protein intake: Muscle hypertrophy, Hypoenergetic weight loss, Recovery from intense exercise, 
  • Potential problems with high-protein diets
  • Conclusions / Summary: Context Statement

Podcast Episode Transcript: Download PDF Copy

Key Paper(s) Discussed / Referred to:

Related Podcast Episodes:

Check out our other podcasts, publications, events, and professional education programs for current and aspiring sports nutritionists at and follow our social media outputs via @TheIOPN



We Do Science Podcast
"High Protein Diets: In Context" with Professor Kevin Tipton
October 4, 2021






[00:00:00] LB: Hi, and welcome to Episode 164 of the Institute of Performance Nutrition’s “We Do Science” podcast. I am Laurent Bannock, the host. And today the podcast in question is all about protein. Now, yeah, that's not exactly a new topic for this podcast. But given it's such a big area, I felt that we needed to dedicate a specific podcast with our very own Director of Science and Research at the IOPN, Professor Kevin Tipton, who is a noted world-class expert on this topic, having undertaken decade's worth of research in this area. 


Obviously, Kev is the right guy for me to be talking to about this topic. And I'm talking to him from the perspective of a practitioner or a consumer of the knowledge, the information that exists out there that I use in my own practice with my athletes, my clients, and so on, as do most of you, listeners of the podcast, practitioners, researchers, and so on. We all have knowledge on nutrition. We have knowledge – Well, we have a degrees of knowledge, some of which is better educated than others, of course, depending on the type of listener that you are, whether you're a consumer of this stuff as a recreational athlete, or most of you who are practitioners of some sort, coaches perhaps, and/or researchers, PhD students, and so on. 


So, as I said, we're all familiar with protein and protein nutrition, and so on. But how familiar actually are we with this information with a good degree of context? And yes, I'm using context again. But this is an area that I believe that is a classic case study for why context is particularly important. So what we're going to talk about is high-protein or very high-protein diets. Particularly, it’s relevant to athletes and exercises. And Kevin, I talk about things like what is the term high, or low, or adequate, or inadequate, or deficient? What does that even mean particularly in the context of nutrition for things like muscle protein synthesis, recovery from exercise, or even the prevention of disease like Kwashiorkor, for example? What does that term even mean? And how has it been widely interpreted from the data? Is it being well interpreted or poorly interpreted? Or is it just plain confused, which, of course, you'll find is the spoiler here. There's a great deal of confusion, we believe. Misinformation, misinterpretation on this, which is driving the choices and behaviors that consumers, practitioners, researchers are making. So we're looking to have a good conversation on this topic, the efficacy, the potential dangers, and so on for athletes, elite athletes, amateur athletes, exercises and so on. 


But anyway, before I let you listen to that conversation I had with Kev today, please do check out everything that we do at the IOPN at You can catch all our current and past episodes of the We Do Science podcast there with all the links to the papers and transcripts and so on that I refer to at least for the more recent episodes in the last year or so. You'll find those. You can learn all about our advanced diploma in sport and exercise nutrition, or specifically performance nutrition. It’s practice focused. Lots of fine educational programs out there, including an abundance of degree programs that in one way or the other will cover sport and exercise nutrition. But ours is very much about the practice of sport and exercise nutrition. So do check out that if you wish to specialize as a practitioner in sport and exercise nutrition, that's our advanced level diploma


Part of that program includes a number of projects that we do, including the Journal Club that Kevin Tipton runs, and some of up-and-coming research outputs are also engaged into that program, but it's largely about impacting the wider community of sport and exercise nutrition. It’s our mission at the IOPN, where you'll also see we have other offerings at the IOPN to include our dedicated platform, software platform for practitioners of sport and exercise nutrition, whether you're working with individuals, or with teams. We have now many professional football, rugby, athletic teams and so on are now starting to use SENPRO, which is incredibly exciting for us. And a lot of practitioners around the globe are now using our SENPRO platform to enable them to become more efficient and more effective practitioners in their coaching and management, their client management. So that’s SENPRO. All of this stuff is at 


And now, I welcome you to our conversation today with Kev all about high-protein diets. Enjoy. 




[00:05:14] LB: Hi, and welcome back to the Institute of Performance Nutrition’s “We Do Science” podcast. Now, if you listened to our last podcast on body composition, with Professor Greame Close and Kevin Tipton, you'll have heard a hint as to what this podcast would be about today. And it's true. We do talk about protein a lot. Don't we, Kev? And there's a good reason for that.  You are very much a noted expert on this subject. But the reason why we talk about these things so much is because protein is something that we eat in one form or another every day in most meals, if not all meals, but protein is a topic of interest, of extremely popular interest in the sport and exercise nutrition community. 


And when we talk about nutrition, protein nutrition, we often hear people talk about amounts. Yes, we hear them talk about types. Perhaps an argument will be that dairy protein will be better than a plant protein. But we've then tackled what is better even mean? And how relevant actually is that to real people in the real world? Could you achieve effectively as much with plant-based proteins as animal-based proteins? 


Well, again, the same sort of issue comes up when people use phrases like high-protein or low-protein, because what they're not doing is defining what they mean by high or low. And everyone knows I love context. I love a lot of context. And of course, that term high or low-protein is going to mean different things to different people in different situations. So that's what we decided we were going to talk about today in this podcast is high-protein nutrition, or high-protein diets, or very high-protein diets for athletes and excises. Particularly, that's our focus. And what are the consequences potentially of that, which may be good or may be bad? 


Do you think, Kev, I've managed to sum up the conversation we're about to have?


[00:07:27] KT: I reckon so. That sounds good.


[00:07:29] LB: Great. Well, listen, Kev, you actually wrote a review on this 11 years ago as part of a conference proceedings paper. And it's certainly a topic that we have discussed in the many podcasts that we have done and/or with guests like Stu Phillips, where we have delved into this topic. But it is one that I think that warrants some particular focus, just because there are still myths about the consequences of high-protein diets and/or the relevance of a high-protein diet in different settings. So that's going to be our entire conversation today. But let's just come back to you, Kev. 11 years ago, what made you want to focus on that anyway, at that time? And how do we bring that up to date to 2021?


[00:08:19] KT: Boy, you just opened up a whole can of worms.


[00:08:22] LB: That’s the plan. A can of worms is high-protein, Kev. So let’s don’t worry about it. 


[00:08:27] KT: True. And Luke's doing studies on them. 


[00:08:29] LB: Oh, well, there you go. 


[00:08:31] KT: So it was just a topic that I was asked to for the nutrition society, they asked me to cover it, because there was a controversy. And the controversy, as you touched on it, is, A, what is a high-protein diet, right? Because a lot of dietitians will define it as anything over the RDA, which is .8 or .85, depending on which country you're in, grams per kilo. So some people define it as that's higher if you go to one or whatever. That's a high-protein diet. Whereas, I know guys in the gym, they're eating 500 grams a day. And so they don't think that's high-protein. They think that's what it should be. So what is it? 


Well, do you define it as percentage of calories? Do you define it as grams per kilo per day, and where? Personally, I would say that somewhere in the 1.6 to two is not high. But people, everybody disagrees, and it depends on who they are and what they've done, or how they've been trained, I think, is a big part of it. So I think we should be flexible about it, really.


As you and I both talked about all the time, it's in the context. So maybe one day, it should be one gram per kilo. And then the next day, it should be 1.5, depending on what you're doing that day, what the athlete or the person is doing. So we should put it in context.


[00:10:22] LB: So Kev, this business of high and low, though, that in itself is such a basic term, isn't it? Because, relative to what? And what are we even trying to do? I think if we start looking at things, particularly in sport and exercise nutrition, we're actually using protein in many cases as a tool, if you like, to help support adaptations to training and/or ameliorate unwanted or poor quality weight loss to support high quality weight loss, that sort of thing. And of course, that would warrant a different approach to this concept of high or low-protein. But I think, probably, it would benefit us and the listeners, firstly, to quickly think about why researchers and scientists, for example, will, will use terms like high and low-protein and where that's a problem also. And what is an average person as far as the research is concerned? We can go down that path a bit first before, I think, we get into more real world stuff.


[00:11:26] KT: An average person.


[00:11:28] LB: Exactly. What is an average person? 


[00:11:30] KT: Yeah, that blows my mind really, because it's just so variable. But the implication is, you're correct, is that's what we kind of do when we do studies, right? We do these studies with 10, 12, average people. And so if you think about the way these studies are done, most of the time, it's done in university students. Now, are they average? Probably not, although more and more so, but they are young and healthy. And then we make these recommendations, or we tend to write about stuff based on these students. 


And often, especially in Britain, not so much in the States, because in the States, the ethical rules are different, where you have to include both sexes, unless you're going to inject testosterone or something. In Britain, we can get away with doing studies in males. A lot of what we're making these recommendations and decisions on is based on a very limited population. And I think now it's being more and more recognized that we need to fix that. But, for a long time, we did it because we could, and because we couldn't get funding to do study both sexes. You couldn't double the population or the recruitment. 


So we have to be – Again, as we've spoken about many, many times, I think that we need to be more careful about how we limit our interpretation of this information. And when you go to high-protein diets, as you said earlier, it depends on the situation. I think that, from what I know, my interpretation is that if you're in a weight loss situation and if you want to maintain muscle, then you probably want to be up in the 2 to 2.5 range. But if you're just a person who's trying to exercise for health, or probably even a high-performance athlete, you don't need to be up that high. There's no evidence that that's relative. 


So the care needs to be. It's not one size fits all. But these guys are going up to 500 grams per day. I have not seen anything to support that, other than under massive, but they’re probably massive anyway, because they're in the gym all the time. So I just think we have to be more careful about how we think about this. 


And then if you go to the opposite side. So what's the downside of it? So what was it? [inaudible 00:14:18] did a nice analysis of theoretical metabolic situations where urea genesis went through the roof, and ammonia buildup and all that. And I sort of summarized it in that paper. But that's where you start going, “Okay, where we can start getting into trouble.” But when you do it, it takes a lot of protein to do that. And most people can't tolerate it, the amount of protein. I'd say that I've known guys who are doing 500 grams a day, but they're also, I don't know, 150 kilos. I mean, they're big. They're huge. So it's not really that much on grams per kilo. 


So you have to think about those kinds of variables before you start worrying about this. And I think that maybe one of the themes that we can get to today is within a reasonable amount, it doesn't really matter.


[00:15:23] LB: Yeah. And that's what I want to do. My purpose here is, firstly, we're just tackling this this concept of this popularly commonly used phrase of high-protein or very high-protein or low-protein, but just the blatant lack of context, hence the confusion, because high or low relative to what so what is what we're going to talk about in today's discussion. Because in certain scenarios, like you were saying, what's considered high-protein for general population might be relatively low-protein for a football players, in soccer player, but then that's extremely low-protein for a rugby player. What a rugby player consumes might be even considered low-protein for a bodybuilder. And as you say, that's not necessarily based on what they need to get the adaptations that they want. That's just on the general belief that they need to inhale protein all day long. And is that a problem? Maybe? Maybe not? Because if they're consuming lots of protein, and it's more than what they need, that surplus quantity of protein, is it a problem? Maybe? Maybe not? And we'll tackle that. 


But if they weren't consuming those extra calories from protein, what would they be consuming instead? And maybe there's a benefit to that in certain scenarios. So I think it's a question of us zoning in and out of these different variables and discussing them and arming our listeners with a bit more knowledge so that they can be a bit more critical about approaching that concept of high or low-protein and whether or not it's something they should even be worrying about. Like you say, that obsession with getting lots of protein, and it might be something that's fed by industry more than science and the impact that that will actually have on what you're trying to get out of that high-protein diet. 


But I think the first thing that I think we should get into is this business of is high-protein bad for you, particularly from the more common concern that you might hear out there, particularly from clinicians or dieticians, etc., and those that are working with youth athletes, or college kids, people who are still growing and developing and might be feeling that protein is a problem for that area, that group within our society. I mean, is protein bad for you in the more commonly understood version of that phrase? And we could differentiate that between people with health problems and people who are apparently healthy.


[00:18:08] KT: So everything's bad for you if you get too much of it, right? I mean, you drink too much water, you'll die. So oxygen will kill you if you get too much of it. So, yes, protein can be bad. The question is where is that line? 


And so as I suggested earlier, you can do some metabolic calculations and give an estimate of that. Also, there's no question that physical activity changes that, that when you're physically active, your body will respond and enhances the utilization of the protein. So you can tolerate more of it if you had to. So I think that if you tried really hard, you could kill yourself by eating too much protein. But most people can't tolerate that. 


So let me give me an example. As you know, Olly [inaudible 00:19:11] and I did a study. Well, we published it what, 10 or 11 years ago. Where we fed high-protein to cyclists when we doubled their training volume. And most of them really, really struggled to eat it. And we put them up around three grams per kilo. And they just couldn't – Most of them couldn't tolerate it. And so it's difficult to do. 


Now, does that mean it's impossible? No. Of course not. But on the other hand, if you get too little protein, and that line also is variable. Yeah, sure, you're going to get into health problems. Although there one crazy guy on Twitter who keeps coming up with this, that people don't really need to eat protein stuff, which is I find really funny. Yeah. So anyway, yeah, you can get too low, for sure, because you get Kwashiorkor and other – These metabolic diseases from lack. 


Now, as we've suggested already, where that is I think is dependent on the person and the situation. And it's not every day you need to have this much protein. You need to define – And probably for athletes, for example, it's going to vary depending on the time of the season and the dietary demands that come with the training and the competition. 


[00:20:52] LB: Well, people love precision. Don't they, Kev, though? That's an issue, isn't it? People love precision. They see these ranges of 2.2 to 3.1 grams per kilogram. And if you're one milligram below that, suddenly you're inadequate.


[00:21:07] KT: Well, absolutely. And as if we can actually measure that. As if despite how meticulous I know dietitians and nutritionists are, you can't possibly get within that kind of precision that people are talking, “Yes, I'm going to have 1.67 grams protein today, or per kilo.” What? You cannot measure that. It's just not possible. So that's where I think we get silly. I think if we focus on a range, and that range will vary depending on, again, the cycle of the training and the season. And we should be fine with that. Now, we're going to learn more as we do more research. When I say we, I mean other people. So we need to just keep these in mind and, back to the theme, interpret, and think about the variability that we have to incorporate in what we've done.


[00:22:15] LB: Yeah. And that's this thing where the words high, very high, become open to abuse, don't they? Misinterpretation and so on. Because as you just mentioned, Kwashiorkor is a deficiency state of protein. And you can have an adequate protein intake to prevent a deficiency disease, but it's not going to be adequate for optimal muscle protein synthesis, for example. But of course, it's more complicated than that again, isn't it? Because there are going to be other factors, like is there an exercise stimulus to support that muscle protein synthesis? Or about recovery and that whole side of things, and calories in general? And then, “Oh, the age of the individual, and blah, blah, blah, blah.” So we certainly need to have more. 


[00:23:07] KT: Hey, why are you bringing up age now? No, you're right. You're absolutely right. And there are all these variability or variables that you got to think about and adapt. And so if a nutritionist is going to do their job properly, they don't just take the simple answer, do they? You have to think about these things and adapt your recommendations and what you're doing with your athletes or your – As we talked about firefighters, who they’re their performance people. They have to do these things, especially nowadays. Geez! Seems like need even more.


So we have to think about this and not oversimplify things, but also realize that it's modifiable. So I think that's the thing. I mean, what is a high-protein diet? That's what we're starting with? Well, it depends. I know people hate that answer.


[00:24:09] LB: Yeah. And it does. And we're going to explore some of those dependable variables in a second. But just so we can move past the potential dangers of excessive or high-protein. Again, I use two words there, which mean two different things in two different situations. But the more common potential danger rather than just like a superhero over consuming protein, which you've pointed out, is very hard to do. Incredibly hard thing to do. But there are some people that may not tolerate, use the word tolerate, which I think is that's a great word to use, because people wouldn't normally associate protein tolerance with being a good or bad thing. But there are a certain group of people who may be having high levels of protein could be a problem. What would that be, Kev? 


[00:25:01] KT: I reckon the most obvious one would be people with an underlying kidney issue. So that is the situation that I could see as being a possible danger is that somebody doesn't really know that they've got a kidney issue and then they eat too much protein, and it could exacerbate it. I think that that has to be very rare. But I'm not a clinician. So I don't know what the odds are. But that's really the only time that you're going have something. 


Now, the other situation that people talk about a lot is bones. And that's, I think, primarily based on sort of epidemiological data. But when you actually look at the situations, again, I'm sure that there's a high amount that it's going to get in trouble. But I think it's going to be crazy to try to keep that up. And most of those data are based on, especially studies in Asia, where people, you don't have a good balance. And if you actually – I mean, Mike Rennie used to make this argument all the time, the late great Mike Rennie, where as long as you keep your balance of acid base balance in the diet, it's only when you get out of balance that that sort of becomes an issue with the bone. Now, and also keep in mind, Rennie did some of these studies that bone actually grows better with a higher protein intake. And I think Craig Sale has done so of these studies recently.


[00:26:35] LB: Yeah, we did a whole podcast about this, because particularly in the more alternative natural health nutrition realms, there are people that will bang on about how having an acid forming diet causes problems left, right, and center, which again is an oversimplification, of course, because there are buffering mechanisms within the body and even acid forming foods like high-glutamine containing foods actually aid in the acid buffering process, don't they? But simply not eating enough vegetables is going to be the bigger cause of the problem anyway.


[00:27:18] KT: So if you're eating protein and you’re eating fruits and vegetables, you're probably going to be fine. Now, can I just say that there are a couple of things that have come up in the last few years that are sort of more recent, which is, for example, an altered microbiome? So this has been a big claim. And so, supposedly, what this does is it changes – It lowers your short chain fatty acids and leads to enhanced phenols and things like that. But one interesting aspect of that is that if you're physically active, then that doesn't happen. Again, I know we're talking nutrition, but also we're talking physical activity and exercise and the importance of those aspects of your life. 


[00:28:11] LB: Well, of course. It's a holistic thing. And we don't mean holistic in the terms of alternative medicine holistic. It is the combination of all these factors, the protein and the human being that the protein goes into, and the world in which they operate. In fact, you mentioned the microbiome. I want to stay there just for a second, because it is interesting. I've done a few podcasts with experts on microbiome, and microbiota, and so on. Actually, I've contributed to several position stands and reviews on this topic. 


And, yes, if we were only to focus on a certain type of food, protein, but also sugar, and so on, then it has all sorts of potentially disastrous impacts to the microbiome. But that's over focusing on those, whereas one of the biggest factors that influences the health and variety of these microbiota is fiber, actually, and the lack of fiber, which we get primarily from vegetables, but also carbohydrates are a rich source of fibers. And yes, there's good carbs and bad carbs, and there's good proteins and bad proteins and so on. And this brings us back to this “balanced diet concept”, doesn't it, Kev? What is that? 


[00:29:32] KT: Well, yeah. Okay. So let’s go back to the argument of our ancestors, that we should be eating an ancestral diet. What did our ancestors eat? They ate, basically, whatever wouldn't run away fast enough. Whether that was a plant, or an animal, or a fungus, they ate to survive. And if you look around, you can see the variability in what people lived off of. And you go from the Inuits, which was a high-fat and mostly protein, not nearly as much carbs, to down in Africa where they would eat almost entirely – Not entirely. That's exaggerated. But they had a very large carbohydrate diet. And they were all perfectly healthy. I mean, up to a point, right? Because they had to run away from a lion or something. 


[00:30:31] LB: Very short lifespans for the most part, didn’t they?


[00:30:35] KT: Yeah. But you know what? That’s a little bit deceiving when you think about that, because that is based on infant mortality? 


[00:30:43] LB: Yeah, disease and –


[00:30:45] KT: Well, but infant mortality brings that whole thing way down. A lot of these cultures, if they made it to sort of 10, then they were likely to live to 50 or 60. So it's a little deceiving to say that. But I mean, the point is still there. What they eat, it’s they ate what they could.


[00:31:10] LB: Yeah. But that's an important point here, because it's relevant to this protein conversation. Because, nowadays, we like to reduce everything down. And we don't eat food. We protein and calories. No, we eat food. That's what we actually eat. And in food, there are lots of things. And yes, back in the old days, go back a few 1000 years, when you ate some protein, you were also eating the bone marrow, the guts of the animal, the eyeballs of – I know, it sounds horrible, but that was more nutritious and complete. Plus, you did a lot of repeated sprints and a lot of heavy lifting in order to get your meal. Whereas now, there's choice, excessive choice, and it takes no energy at all to go get these things for the most part. 


[00:31:54] KT: Oh, I sprint to the refrigerator. 


[00:31:56] LB: Oh, I'm sure you do, Kev. 


[00:32:01] KT: But you’re right. I mean, that's absolutely true. And it is one of the reasons that I walk to the store to get my food now, it's just so I get at least that activity, if nothing else, right?


[00:32:14] LB: So Kev, I think just so we can keep this relevant to the topic, that in itself is an important area that we need to get into, is one's view on high or low-protein, or adequate protein, which we've already made clear, needs to have some context. So relevant to what? All listeners are into exercising, and sport, and elite performance, and so on. So this idea of high or very high-protein as it relates to how that comes across to exercises, what do we need to be bearing in mind on this particular topic, Kev?


[00:32:55] KT: So, in my mind, there are a couple of things that are relevant here. And one is that physical activity enhances your muscle’s ability to utilize the protein. So from that standpoint, you could argue that you actually need less, right? And in fact, we know from – What was his name [inaudible 00:33:19] study from 100 and some odd years ago, that you can gain muscle a relatively low amount of protein or what people now consider low, so around one gram per kilo. So you can gain muscle on that amount of protein. It doesn't take – As long as you're doing the physical activity that you need. On the other hand, you could argue that you need, if you really want to gain the most benefit from it, then you want to push it up a little bit. So I feel like I'm kicking a dead horse here. But it depends. It depends on what you're doing. 


[00:33:59] LB: No, it does. And what you're doing, I want to just stay on that, because that is incredibly relevant to this topic whether something is high enough, low enough, adequate enough. Because even the phrase exercise is a bit generalized, isn't it? So that context changes depending on the types of exercise. And then there's, “Are you doing enough of the exercise? What types of exercise?” Tell us a bit more about that, Kev.


[00:34:27] KT: So the way I see it is, okay, so depending on who you are, right? I mean, if you're a high-performance rugby player, for example, you're going to have a different requirement. But as I've said, you got to vary that during the season, right? And you got to balance it with the carbohydrates and the other nutrients that you need. For us mere mortals, I think that the variability that you can tolerate is pretty high. And that we shouldn't – Again, too many people focus on trying to get this precision that, first, they don't need, but also they can't measure. 


And so, I mean, if you think you're getting 35 grams from a chicken breast, you're going to have to measure that very carefully. And it's going to vary by five grams of protein depending on what part of the chicken like cut out and which chicken it was. Again, the precision is just not there. And people, I think, focus too much on this, and not just try to eat a well-balanced diet. 


[00:35:46] LB: Now, that term, I think, passed over too frequently in the sport and exercise community. If you hang around in the more health, public health, clinical areas of nutrition – Part of my training is in that area, I feel concerned. Where, I guess sort of when you're talking about, say, bodybuilders, or whatever, consuming protein, you're often see them with their chicken and broccoli in plastic containers, and so on. And there's nothing really else there. And yes, that will help achieve their immediate goal, which is to increase muscle mass. And I'm sure that they're doing great amounts of the right kinds of exercise, and so on so forth. There may or may not be some chemical assistance in certain people, but for many there isn't. 


But we've already mentioned things like concerns over the microbiome, for example, and that's going to be heavily influenced by the lack of fibers and other substances that benefit the gut microbes and influence the environment within the gut, which are going to be found in a wide range of fruits, vegetables, and other fiber-containing compounds. And there's also where these organisms themselves come from, the whole another conversation, which I have done in other podcasts. But you will see people arguing the case for there's absolutely nothing wrong with over consuming, overfeeding protein, because if they weren't doing that, they might be consuming other types of foods like sugary foods or other things. So it is argued to be a strategy that can support weight loss or strategies to support favorable changes in body composition that results in higher levels of muscle and less body fat. But again, how long term are these observations? And how much are they actually looking at these broader factors that impact health that we might attribute to a more balanced diet? What are your thoughts on that, Kev?


[00:37:47] KT: I mean, that's a challenging question, of course, because who knows? When you talk long term, you got to go to epidemiology. And then you have all the challenges of trying to interpret epidemiological data. 


[00:38:04] LB: But what does even long term mean? Is that a week, two weeks, one year, two year, ten year? 


[00:38:09] KT: We got long term, short term, high-protein, low-protein. What does it all mean? And I wonder if we go back to the ancestral human kind of argument, where I think humans are very adaptable. And I'm sure that there are certain people that better to this than that. There's no question. Otherwise, we wouldn't get cancer and do all these other things. But the whole story of my granny, who, she died at 99. She drank a bottle of bourbon and smoked three cigars every day, which is not true. But there are people who do that, right? But that doesn't suggest that you're going to go to the motorway at rush hour and run back and forth, because you might make it. 


[00:39:03] LB: Yeah, absolutely. 


[00:39:06] KT: So you try to look at the broader terms. And as far as protein goes, I think again, I would suggest that people eat somewhere in the range of one and a half grams per day. If you're trying to lose weight, you might want to go up a little bit higher. 


[00:39:24] LB: Kilogram of bodyweight, right?


[00:39:26] KT: Yeah, sorry. Thank you. Yeah, that would have been –


[00:39:29] LB: Whoa! I’m totally overfeeding. 


[00:39:35] KT: Yeah, thanks for pointing that out. But I think that most people get too engrossed in the detail, and that there's no rationale for differentiating between 1.2 and 1.5. In fact, you can't measure that. So it's –


[00:39:54] LB: Well, in all likelihood, Kev, people are going to vary. You talk about tolerance and so on, but of course there is this thing that’s going to be inter and intra individual variability. Maybe you could explore that a bit, because these are the things that are more controlled. Or when researchers, not all, but a lot of them tend to average out, that they publish means as opposed to individual data. Whereas if you delve into the data, you often see quite a lot of variety, don't you?


[00:40:22] KT: Well, I've made it a point in the last 10 years or so to publish the individual variability for muscle protein synthesis, for example. And you can see how broad it is if you look at our papers. Yeah, you're absolutely correct, that people, their response varies. And you can do exactly the same thing to the same person or to two different people and you can get a 50% difference in the response in muscle anyway. 


Now, and that's muscle protein synthesis. And if you go and look at things like the molecular signaling pathways, it's even crazier. And part of that is measurement. But part of it just the individual does respond differently. 


[00:41:13] LB: So Kev, there's going to be some gray areas, obviously, because we have to face one important factor, and that is just the individual preferences that people have. We can cater for that. There was absolutely nothing wrong with – I think we're arguing here that, yeah, you can consume higher protein than you actually need. But whether you should or not is down to these variables that we've discussed. And what are the consequences of that? Well, it might be the lack of fiber. It might be the lack of vitamins, minerals and other nutrients, or it might be absolutely no problem at all. But these ranges will vary, and experimentation and so on will pretty much show you what you need. But what about in people who are in a very – That difficult area of being in a hypo-energetic weight loss situation? And I'm thinking, yes, elite athletes where we start thinking about relative energy deficiency and so on, or, of course, people who are genuinely under eating because of their approach to their diet and potential obsession on the aesthetics and so on, which is a powerful driver for food choices of course.


[00:42:29] KT: Well, yeah, there's no question that that's a consideration. And so, again, I think it comes down to the situation, because one danger is, especially if someone's trying to stay active, and particularly if you're a high performance athlete. But you got to balance how much carbohydrates you need, because that – At some point, that's going to be limiting. So if you're eating more of your energy from protein and not getting enough carbohydrates, then that could be an issue. But again, it comes down to – And this is the challenge for the nutritionist out there. You've got to think about the situation in that particular person at that particular time. And that's a challenge. And there's no overarching answer to this.


[00:43:27] LB: Okay. Well, I think what we're saying here is, it's like everything that we look at here, you just need to understand the strengths and limitations of the knowledge, the science, the data that's on this and not run buck wild with the crazy myths on that. But actually, depending on the context, it could be right, it could be wrong. You just need to understand what you're dealing with. Understand the tools in your toolbox, as I always say, but also think about the relevance of this. It's a matter of choice. And people do choose for different reasons. But sometimes those reasons are based on a poor understanding of what is required, for example, to achieve optimum levels of muscle protein synthesis. I mean, face it, a major reason for having lots of protein is going to be, as I see it, two real reasons. One is so that they get the gains from the heavy lifting, the hypertrophy gains. And the others are, it's a useful strategy in weight loss, whereby it can help control appetite and various other things as compared to where you might get those other calories from, which may be less helpful in that regard.


[00:44:39] KT: Well, yeah, I think those are both good reasons. I'm less convinced about the appetite thing. I'm not sure that that's always effective. But hey –


[00:44:51] LB: Yeah. But let's talk about that, too. Because I think it's interesting because, again, protein – We've been talking more about protein as a macronutrient and so on, and maybe less so as a method of potentially affecting appetite and the risk of overconsumption of other foods. And in fact, again, that's based on information that may have been interpreted a little bit too heavily towards the myths maybe that are attributed to it, as opposed to reality. And of course, there's going to be a difference between, say, whey protein and a chicken breast with the skin on and its impact on appetite and insulin and all that stuff. What are your thoughts on that now that you've I raised your eyebrows on it so to speak?


[00:45:40] KT: Yeah. I opened up another can of worms, didn’t I? So there's definitely evidence, of course, that protein has higher satiety value than the other macronutrients. And there's even studies suggesting that, like you said, whey protein might have a better satiety value than even casein. But I don't think the evidence is overwhelming. I think that's kind of variable. It's certainly not my area of expertise. So maybe people out there can correct me, but it seems to me that it's variable enough that I would just not worry a whole lot about it. Now, again, I would argue that, hey, why not? Especially if you're looking to lose weight, then increase the protein a bit. But I don't know that it's overwhelming evidence, let’s put it that way. I'm not convinced.


[00:46:41] LB: Yeah. This is a common theme in the last, well, several 100 – Well, we're not quite into 200 podcasts. I'm still in the 164, I think, this one's going to be. But it is a common theme, is we just don't know actually. Like there's what we think we know. And that knowledge is based on combinations of either very good scientific evidence and/or some good hunches by people working in the area for a very long time. But also, there's just a hell of a lot of speculation. And speculation isn’t always bad, because that's what leads to more studies, doesn't it?


[00:47:17] KT: Exactly, exactly. I mean, I think if we had to sum up extremes, probably not the best answer for most people. And the situation, you need to fit the situation as best you can. But I still wouldn't go to huge extremes. 


[00:47:38] LB: Yeah, I completely agree. And I've said this a lot of times, but I really wish we'd start talking about nutrition, particularly when we're looking to apply the information into practice without actually bringing the word food in. And, yes, we sort of joke about balanced diet. And this idea of food first. That's gone too far as well. In fact, I know, Graeme hinted that he's got a paper where it's going to be a bit more about food first, but not food only. And I can't wait to have that conversation with him when that paper comes out. But it is absolutely a risk, though, in the sport and exercise community that we talk about calories, we talk about food, but we don't talk about other things like fiber and so on. So it's great to know that researchers are now looking into things like microbiome and various other things. But it's absolutely certain case that we are not just athletes or exercise. We're human beings, and we have needs that goes beyond just smashing in the protein.


[00:48:41] KT: I think that's exactly right, that people get too extreme, or they want to get too extreme, because they want to try the next best thing. Whereas, like we said, as a human, we can adapt to a lot of different diets. Now, not to say that they're all good, but you can adapt to them. So can I just address one more thing about high-protein is a concern? Because I’ve seen it put out there that high-protein, and especially branched-chain amino acids, leads to an overstimulation of the mTOR pathway, which leads to decreased longevity in pretty much every species, but humans. 


And, of course, I've seen this enough that I just wanted to bring it up, that, again, I think we are over interpreting these data, because what they're doing is giving really, really high amounts to worms, or rodents. And I don't know how that applies in a human physiological situation. And so I think we need to be careful about people interpreting what they call a high-protein diet, and it's killing – You're going to live less. Because, for sure, we know as you get older, you need muscle. Muscle is the most critical tissue for all sorts of reasons. And if you're not eating enough protein, you're not going to have enough muscle. And so let’s even say that you're going to live five more years. But if you're going to be living those five more years sitting on your sofa, what good is that? So I think we need to be careful about some of these problem with high-protein diets. We don't even really know what that means in humans, right? I mean, again, all these data are based on subclinical situation. 


[00:50:52] LB: Kev, I think a problem is that when people use the phrase protein, high-protein, the mind goes straight to animal sources of protein. And of course, we're not suggesting that animal protein is the only way to go, is the a convenient way to go. But it's not the only way to go. Plant protein, as you've mentioned many times, will almost certainly do the job. It's more of a question of are you getting enough? And that's what we're talking about. But what does that word enough mean? And it's not actually what most people refer to as high or very high-protein, adequate protein in this situation is what range which we’ll leave people with?


[00:51:30] KT: Well, again, most people, if you try to eat two grams per kilo per day, most people aren't going to tolerate that. They don't like it. I mean, there are – Like I say, I've known these guys that are eating 500 grams a day. But they are, like I say, 150 kilos. So when it comes down to it, it's not as much. So try it, and see how long you can tolerate that.


[00:52:03] LB: Yeah. But not at the expense of some other things that are in the diet, and that's, I guess –


[00:52:09] KT: Well, yeah. I mean, so there’s tolerance just because it’s just – Whenever you get too much of something, you're going to go, “Whoa, I don't want that.”


[00:52:20] LB: Yeah. Human nature, Kev. 


[00:52:22] KT: Aye. But also, also it’s just like, “Hey, you know what? I'm going to want this or that.” Now, again, there are plenty of people out there on the paleo diet, and they're trying this and that. But the people that I know that have tried this for any length of time back off. 


[00:52:40] LB: Yeah. But also, you talk to a lot of these people, and they've done paleo for X amount of months or years. And then they've done plant-based for X amount of years. And then they've been whatever. That’s the thing. And I think the point is that human, we should not underestimate just how robust and adaptable the human body is. There are many other factors like just getting enough sleep and not watching the news all the time and being happy and getting enough exercise. And actually, these are –


[00:53:11] KT: I still would argue that if I had to do one thing, it would be staying physically active. That to me is the most important thing. All the evidence supports that, that you can adapt to lots of different diets, but if you're not physically active, then it doesn't matter. You're going to end up being in trouble. Unless it's like my fictional granny who has this crazy thing.


[00:53:38] LB: Well, on that point, I mean, a lot of the things that we've delved into today, I've done podcasts on. And I really recommend listeners, do listen to the podcast that I did on the microbiome and the fiber gap. That was a fascinating with a world leading expert on that topic. It wasn't about sport and exercise specifically, but that's it. But also on this topic we're just talking about now, we did a podcast on this idea about running a bad diet. And that was with Michael Joyner and Stu Phillips, and definitely one of my favorite pods of all time, which they thoroughly argue the point that physical activity is the most important thing that we really should be dealing with. 


But look, Kev, look, we could talk about this stuff forever. 


[00:54:24] KT: We always do. 


[00:54:24] LB: There're more pods to come. Of course, I've got lots of other guests lined up. So it's not just giogn to be you and me talking. We'll have some others. But I always enjoy our chats with you, Kev, and it's always a pleasure. And having you on our team is awesome, as always, for reasons that I think are obvious when people hear us talk. You're a real asset to us. Thank you.


[00:54:46] KT: Well, I'm very happy to be on the team. And thanks for having me. But I’ll totally enjoy your time in Belgium. 


[00:54:50] LB: Well, I should point out that those that are listening, a lot of these stuff that we're wrestling with is a topic that – Sorry. Is what we do in our journal club for our students at the IOPN. If you want to do more than just listen to our podcast, feel free to join Kev and our students on our journal clubs. You have to be on one of our programs, but that's the benefit of doing it. 


[00:55:10] KT: Well, t hat’s one of my favorite times. 


[00:55:12] LB: Yeah, well, we have good discussions with the students, Kev. All right. Well, look, let’s just bring it to an end. We haven't covered everything known to man on this topic, but I think we've added to all the other podcasts that we've done on this. And we look forward to bringing another podcast back to you all very soon. Take care, everyone. And once again, thank you, Kev. 


[00:55:30] KT: My pleasure.