ZOE Science & Nutrition - Protein & exercise: The secrets of healthy aging?

Episode Date: May 25, 2023

As we age, our bodies undergo numerous changes, including a decline in muscle mass and cognitive function. For many of us, exercise and diet play crucial roles in maintaining our health and well-being.  But how can the protein we eat affect our abilities to exercise and stay healthy as we age? It can be difficult to separate fact from fiction when it comes to the effects of protein. How much do we need? Is it better to eat protein before or after exercise? And what roles do protein and exercise play in brain function? In today’s episode, Jonathan is joined by Prof. Ben Wall, an expert in nutritional physiology at the University of Exeter. Together, they unpack the latest scientific research on the connection between protein consumption and exercise. Prof. Ben Wall shares his insights into the optimal amount and timing of protein intake for building and maintaining muscle mass, as well as the potential impact of exercise on cognitive function and brain health into later life.  Download our FREE guide — Top 10 Tips to Live Healthier: https://zoe.com/freeguide Timecodes: 00:12 Introduction 28:21 Quick Fire Questions 02:54 Do we need to eat proteins right after exercise? 03:34 What is protein? 04:45 Why should we care about exercise? 05:36 How does exercise help with healthspan? 07:41 What are the benefits of exercise? 07:57 Does exercise improve brain function? 11:23 Where do our muscles come into this conversation? 12:09 What constitutes an unhealthy muscle? 13:00 What's the difference between a healthy and unhealthy muscle? 14:18 How does protein fit into the idea of healthy muscles? 16:03 What about the concept of breaking muscle. Is it good for us? 18:13 Do we need more protein to help build muscle? 20:07 What is the anabolic window and Is it a myth? 21:54 Is it fine to listen to our hunger pangs post exercise? 23:01 How does protein impact menopause and bone health? 25:04 Is there a maximum amount of protein our bodies can absorb? 28:14 What is the right amount of protein to eat? 30:02 What is an 'adaptive response' to exercise? 31:17 How much higher RDA do we need if we are exercising? 33:31 Are we already eating enough protein? 35:51 Why does muscle mass change as we age? 36:18 Do we put on weight when we age? 36:59 How do our bodies respond to protein as we age? 41:38 How to balance protein and exercise 42:33 Where should we get our protein from? 46:43 Plant vs animal based protein products 51:26 Summary 55:12 Goodbyes 55:27 Outro Mentioned in today’s episode: Ingested protein dose response of muscle and albumin protein synthesis after resistance exercise in young men: https://pubmed.ncbi.nlm.nih.gov/19056590/ Anabolic signaling deficits underlie amino acid resistance of wasting, aging muscle: https://pubmed.ncbi.nlm.nih.gov/15596483/ Food for our future: The nutritional science behind the sustainable fungal protein — mycoprotein: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10131050/ Follow Ben on Twitter : https://twitter.com/benjamintwall Follow ZOE on Instagram: https://www.instagram.com/zoe/ Have an idea for a podcast? Contact Fascinate Productions to bring it to life. Episode transcripts are available here.

Welcome to ZOE Science and Nutrition, where world-leading scientists explain how their research can improve your health. Protein, one of the building blocks of life itself. It plays a vital role in keeping us fit and strong, which as we get older becomes increasingly important. Around the age of 40, our muscles begin to shrink, leading to a loss of strength and frailty. Eventually, even getting out of a chair becomes impossible.

Eating protein is a necessity to maintain our muscles and prevent this decline. This is why protein is now so widely discussed, and so many products now proclaim high in protein. Myths circulate online about plant versus animal protein, when to eat it if you're exercising, and concerns about whether we're getting enough. If things weren't confusing enough, brand new scientific discoveries have revealed that much of what we used to believe is wrong. In today's episode, we get to the bottom of all of this with help from an expert guest. Ben Wall is Professor of Nutritional Physiology at the University of Exeter,

where his research focuses on the role of exercise and dietary protein in supporting healthy aging. Ben, thank you for joining me today. It's a pleasure. Thank you for having me. Why don't we start with something we do every time on this podcast, which is a quick fire round of questions. Ben, we know this is very hard for scientists because you have to give us a yes, a no, or if you have to, you can give us a one sentence answer. Are you willing to give it a go? I'll give it a try. And as usual, Ben doesn't know any of the questions that I'm going to ask. So let's see. All right. Is it true that if I stop being active, my muscles will shrink within days?

Yes. If I don't eat enough protein, will I lose my muscles? Somewhat. Okay. As I get older, do I absorb less of the protein that I eat? Yes. Okay. And given that, does that mean that when I get older, I might lose muscles because I'm not getting enough protein? Yes. Okay. This is what I really want to ask. Do I need to eat protein straight after I exercise? No. I hope my trainer's listening to this. Is animal protein better than plant protein

for building muscles? Not necessarily. Brilliant. We'll talk about this, but it's definitely one of the first experiences I had, the first time that I went to the gym, which was probably about a decade ago, and I got introduced into this whole world of lifting weights and things like this. And I remember one of the very first things was like all the rest of the lifestyle that you're supposed to put around going to the gym. And definitely one of the things I was told was, oh, you have to eat protein like immediately afterwards straight after you finish this exercise otherwise

all of that pain that you've gone through is basically wasted yes and i think it the general consensus now would be that that's somewhat of a myth wonderful well i think we'll get into that into a bit more detail but why don't we start just at the very beginning and you know some of our listeners will have heard you know a previous a previous podcast that we've done talking about protein and some of them won't. And for all of them, I think it's really easy to get confused because the protein stuff is all a bit complicated. Could you just start with what is protein and how is it different from carbohydrates and fats? Of course, we eat for various reasons, of course, but one of the main aspects of our diet is energy. We get energy from three major sources, which is carbohydrates, fats, and protein, as you say.

Carbohydrates and fats can broadly be viewed as fuels. They do have other roles, but they're kind of bulk fuel that we use to actually just carry out all the processes that our body require. Protein's a little bit different. It provides the structural molecules that we need to build up our body, replace all the aspects in our body that are actually made of protein, which is all the structural elements that we have, all our structural tissues, our enzymes, largely hormones, everything that makes the body work really is constructed of proteins. And this is where we- So it's not just our muscles then that protein is for? No. I mean, muscle gets a lot of focus because it adapts and it's also a big

proportion of the protein that's in our body. But no, everything that's a tissue structure comprises protein in the body. And presumably like everything is a tissue and every part of me is full of these tissues you're describing. Exactly. Yeah. Got it. And so I'd love then to sort of talk maybe about how it fits into exercise, which is sort of the main topic we wanted to talk about today. Maybe we could just start with, like, why do we care about exercise? So I'm 48. I'm not an Olympic athlete. Anyone who sees me will know this as the team behind is laughing at this point. Why should I care about exercise? And what's the role of muscles within that question of like,

why should we care about exercise? Okay. I mean, we care about exercise on different levels. We, of course, as you point out, we've got people that care about the highest level of performance and maximizing every tiny bit of performance, more at the elite level. But we also care about exercise from a public health perspective. Generally, most people would regard exercise as a cornerstone of a healthy lifestyle. Usually, they would tie that into a good diet. The question tends to be, what kind of exercise should we do?

How much? And what is a good diet? And this is because exercise has a lot of proven impact on remaining healthy for longer, even just living for longer. Isn't that right? Yeah. And I always look at it that the historical focus on healthy living and exercise was about living longer.

I think we've moved a little bit more towards the idea now that we can just live better. So the old expression is rather than having years in our life, we want to have life in our years. So there's a big focus on exercise to have a better health span necessarily just in a lifespan. And so can you help us understand a little bit i guess why is the exercise helping with that health span and how does that tie into caring about your muscles and things like this because you might say oh so i need to like walk a certain amount in order to be healthy but why wouldn't i try and get away with like the lowest number of muscles to do that why would i care about ever doing something where i'm you know lifting? It could just help to unpick that a bit more to help us understand what would be the

objective. Someone's listening to this and they're probably saying, I'd really like to have that health span for as long as possible. I think it's something we talk a lot about on this podcast. Can you help us understand a bit more how these aspects of exercise work and how do muscles and supporting muscles fit into that? Of course, I suppose we could view it as different gradations of priority. So there will be some people that just want to get moving. They want to do more steps per day and things like target step counts often work to get those people moving. Some people want to do far more intense exercise, whether that's running, resistance training, games-based sports, things like that. Everybody's got their own different goals. Broadly, when I'm asked what is a good kind of exercise, whether that's running, resistance training, games-based sports, things like that. Everybody's got their own different goals. Broadly, when I'm asked what is a good

kind of exercise, what exercise should I do? I think the most pragmatic answer to that is whatever you like to do, whatever you will stick to doing, because generally doing a bit more is generally better, at least from the perspective of health. Exercise generally, and I guess broadly across exercise modalities improves the physiological systems across the body almost exercises medicine is a nice expression because it's basically improving the physiological systems across the body can you give us a few examples sorry just to explain because you use some fancy words there for a minute which sound great i love the idea of improving all these systems what are they could you give us some examples um so for instance the

cardiovascular system will react very positively to exercise. You'll have benefits to cardiovascular health, so that whether that's your vasculature in terms of disease risk will reduce. So this is like your heart and your arteries and all these sorts of things? Absolutely. Your lung function will improve. Increasing attention is paid on the actual cognitive function, improving with exercise. And is that true? Does your brain actually improve with exercise? Absolutely.

There's lots of evidence to suggest. I mean, one of the things that's always nice about brain function and exercise is the tight correlation that's been observed several times between brain function and the amount of exercise people do. Is this really true? Because it sounds, I was brought up that like your brain and your body are two completely different things. I was not brought up in a household that was really big on it.

My mom's listening to it. I love you, mom. But that was definitely not like a big part of my life. So I'm rather stunned that you're saying if I do exercise, actually, my brain is going to be healthier. Well, I wouldn't purport to be a cognitive scientist, but the nice correlations have always been observed. I've always begged the question, which is, do people exercise and then their brain becomes healthier or is their brain healthier and therefore they do more exercise but there's certainly nice correlations between brain health and exercise and it's a it's a really emerging area of what the mechanism might be i think lots of people listening to this worrying about dementia alzheimer's things like this it sounds like you're saying you know exercise potentially it sounds like

could actually help with that absolutely i mean I would probably say it's a reasonable comment to say there isn't a physiological system such as the brain, the heart, the lungs, the musculature, the skeleton, that hasn't been associated with positive benefits of engaging in regular physical activity. Got it. So just to make sure I've got that, you're sort of saying, if I'm doing regular exercise, it's going to help almost every part of my body. And that's not just saying it makes you stronger. You're saying actually it helps my, I'm less likely to have a heart attack, less likely

to have a stroke. I might be less likely to have dementia. Hence your exercise is like taking medicine. Absolutely. And I guess that's when we talked about whether or not exercise is going to improve the length of your life and the strength of your life. The next level down is this is why, because it's improving all the how we function every day, which is again, making us live longer, but making us live better. The next level of analysis down

after that is probably what kind of exercise are we doing to target different organ systems or functions of the body that we care most about. And how do the muscles fit into this? Because I think that's where we started with this and the food we're eating to support them. Why do I need to make my muscles any stronger in order to do any of this? There's a very strong correlation between the amount of muscle tissue we have and how strong it is and how well we live, particularly as we get to our older years. So how much we have and how strong it is, is important. But it's not just how much we have and how strong it is.

It's also how metabolically efficient it is. Muscle tissue isn't just what we use for locomotion, for moving around and lifting things up. It's also what we use. You're making me smile because locomotion makes me think of that 80s song. It was about the last time I've heard anybody use it. Gone. So that's like walking around, doing the locomotion. Indeed, doing the locomotion.

But it's also what we use to metabolize the majority of our nutrients. So when we take in a meal, whether it's carbohydrate, fat or protein, by virtue of how much muscle tissue we have, even in a relatively lean person, muscle tissue is the depot for disposing of all those nutrients and using them to create energy or to create new proteins. Can you help explain that a bit more? Because I think I have quite a simple idea of this, which is like, well, it's really your guts breaking all of this stuff down into like little pieces, and then it's sort of getting dispersed in your blood and put somewhere. Can you help us to understand a bit more what the muscles are doing, as you just described?

Absolutely. Take, for example, one of the most commonly used markers of metabolic health, which is how much sugar we have in our blood. That sugar in the blood is there largely because of what we've eaten. So if we eat a carbohydrate-rich meal, as you point out, that carbohydrate will be digested, it'll be absorbed, and it'll enter into the bloodstream. So the blood sugar will rise. In a healthy individual with a reasonable amount of muscle tissue, and also that muscle tissue's sensitive as well, so metabolically healthy, the muscle will suck up that sugar out of the bloodstream. Which is why if we're metabolically healthy, we have relatively stable and low blood sugar.

So the muscles are playing this really important role in sort of dampening down what would otherwise be these big spikes. Exactly. And they can sort of take it in. It's like a reservoir. And you described it as though if they're metabolically healthy. So what is an unhealthy muscle and what happens in that situation? Well, if you consider the example we've

just given, which is taking up all the sugar after a meal, imagine if we lose some of that muscle tissue or that muscle tissue reduces its ability to take up the sugar. If we take in the same amount of sugar in our diet, that now stays in our bloodstream and gives us elevated blood sugar, which we often use as a marker for pre-diabetes or when it becomes too regular or too high, we call it type 2 diabetes. So you've got two aspects there, which is you need sufficient amount of tissue to act as this reservoir, and then you need that tissue to be healthy. So what we say quality muscle. So what we've just described there is something called the insulin sensitivity of the muscle, which is the ability of the muscle to respond to the hormone insulin to take up sugar into itself and act as that storage

depot if it does that let's say in somebody who's regularly exercising it can do that very sensitively and it can use all that sugar for exercise and it also has fats in the muscle that it uses for exercise it uses as the fuels. When muscle tissue becomes less healthy, it reduces its ability to use both that fat and the sugars for actually creating energy. So it stays in there as a kind of inert molecule that basically just causes problems with the process of disposing of nutrients. This basically leads to the overspill of having additional fats and sugars in the bloodstream. And this is what we call metabolically less healthy. And a lot of it stems from the muscle being less healthy. So that's really interesting. So you're saying that, you know, there's almost like two things

here. One is that you need a level of muscle in order to do the sorts of exercise that's important. And I think we'll talk a bit later, I think about aging, where I think we all know that you can start to reach the point where you just can't get around and you have this massive loss of quality of life. But there's also something here really about the quality of the muscles really affecting health. And that feels like a brilliant point to ask about how we get there and maybe how does protein fit into this story? You said that protein is important for helping to build all of these different parts of our body. How does the protein fit in and the nutrition fit into this idea of healthy muscles? If you consider what we've just discussed about trying to improve the quality of muscle tissue,

we often use terms like reconditioning. We want to recondition our muscle tissue, which is quite an accurate term because if you engage in physical activity now, whether it's going for a run or lifting weights, what will happen in the hours and days following that bout of exercise is you will recondition your muscle tissue. What we generally mean by that is you're going to break down and rebuild up the proteins that comprise that muscle. Relatively slow rate, muscle proteins turn over like all proteins in the body do, relatively small amount, about one or two percent per day, but that still means over weeks and months that you're replacing all your muscle proteins. This is what we mean by

reconditioning. The reconditioning that you're going to do will depend on the goal that you want. So we've just talked about increasing insulin sensitivity. If you want healthier muscle that's better at doing that, you want to replace the proteins that make you more insulin sensitive. If you want to be stronger, you want to replace and add the proteins that make you stronger. That's going to come ultimately from meals. So in the hours after exercise, we were going to consume food. So we've got two stimuli there. We've got the exercise itself is stimulating the muscle to rebuild itself. And we've got the nutrition is providing the building blocks and also stimulus to help

it rebuild itself. So it's a really a synergistic effort between exercise and nutrition to actually recondition that muscle to become better, healthier, stronger, faster. And one of the things that, you know, when I first got introduced to this idea of the gym, as I said, which I'd never understood before is like, you don't go to the gym and just sort of by doing some exercise, your muscles actually grow. Actually doing this really weird thing where you go into the gym in order to like break your muscles, which sounds crazy right there's not many other things in life where i'm gonna make this better by going in and like smashing it up but sort of what i was explaining to me is like you're going in and you're you know you're lifting these things or you're running whatever these things are you're

actually like breaking your muscles how does that fit in with this idea of just the sort of steady sort of you were saying one to two percent of these things are just sort of turning over why do we think it's a good idea to to break these and could you just help me puzzle this one out it's a nice way of putting it because it is it's pretty accurate what you've just said i mean if you consider that just sitting here we're building up and breaking down all our muscle proteins anyway relatively slowly as, as I've said. Because that just happens a little bit steadily every time, like it's getting worn out and it's being replaced.

Exactly. All protein pools of the body have to replace themselves gradually. And all tissues do this at different rates, depending on their different function. It's basically the replacement of damaged proteins and the renewal of new proteins. So this is a constant process that's always going on. What you said about going to the gym and basically breaking something down is true because there's some nice early work that demonstrates that if you go and do a single bout of heavy exercise, you increase the rate at which you're breaking down your proteins and you increase the rate that you're building them up.

So as a result of that, the overall turnover rate is increasing. And this is the reconditioning response of muscle. However, what that work also showed that if you, as often is done in laboratory-based experiments, do this in young, healthy people who are having no food, the rate they're breaking down their muscle is still actually greater than the rate they're building their muscle. So without the addition of food into the equation of exercise, you will still remain in a situation where it's actually quite difficult to build muscle or build stronger, faster muscle because the exercise itself has also broken down some of that muscle. And so you need to eat enough protein to both deal with just the constant background level of needing to replace a fraction of the muscles and then because you're doing this extra exercise you're like you're breaking down more so you've got to get like more protein in order to

first i guess just fix it back to the level it was and then for people who are listening it's like yeah i want to have more muscles then they need to have even more protein on top yeah i mean it refers back to the initial question you asked me about having protein straight after exercise because once researchers had demonstrated that while exercise was increasing this building up of proteins, it wasn't doing it enough to actually outweigh the increase in breaking down of muscle. They, of course, performed an experiment under the laboratory conditions where they immediately gave somebody protein after the exercise. And this solved the problem because it meant that you've now got all the extra protein

coming in from the gut. You've got the anabolic effect of the exercise. And hey, presto, you've got a much more anabolic environment. So therefore everybody said you have to have protein directly after exercise to create this muscle building response. But of course, this was a virtue of doing things under laboratory conditions where you're tightly controlling human volunteers for 10, 11, 12 hours with various different invasive procedures happening to them, not having any other food or anything else, rather than looking at whether or not that would be different on meals of different times of day, for example.

So while those experiments did show quite simply that the addition of nutrition or dietary protein ingestion with exercise was better for building muscle than exercise alone, they didn't really address when we should have it or how much we should have. And for normal people, so again, putting aside the Tour de France cyclists and Olympic athletes that sometimes people are talking about, for normal people, including people who are maybe are working out a lot and really trying to be healthy you're saying you don't really need to worry too much like you might finish your gym and not eat for two or three hours you don't think it really makes any difference no i mean the attention then was paid on what was called the anabolic window and it was often purported that the anabolic window was within an hour could you just explain

what the anabolic window absolutely sounds cool but It sounds cool, but you've lost me. It sounded so cool that it created a lot of traction without so much research behind it. That happens on the internet a lot. It basically is the term used, the idea of when you finish exercise, you have an anabolic window. And this window is a time period in which you should eat protein in order to maximize the gains of muscle tissue that you've achieved during your workout. So it's exactly what you sort of think. Will I lose all those gains of muscle if I don't have protein straight after exercise? And it's unfair to say that the evidence didn't support that claim because that's all the evidence we had, which is it was either protein after exercise or not, and you had a greater muscle building response. But research then went on to look, does it matter if we delay that protein by an hour or two, or is there a difference because

does every meal following exercise for one, two, three, four hours, or even up to a day or two, have the same response in terms of the additional effect of exercise and nutrition? And I think the consensus is broadly that I've heard it described by others quite articulately as it's rather than an anabolic window, it's more like a garage door that's left open for at least a day or two. And really what happens is we do a bout of exercise. It does give our body the stimulus we need to remodel itself. And then we extract the nutrients we require from several meals for the next day or two quite effectively without worrying too much if it's in the first hour. The body doesn't know if it's one hour or one hour, 10 minutes. I think that's incredibly reassuring. And we had a previous podcast with Christopher Gardner,

who's a good friend of Zoe's. And he gave this great analogy that I found really reassuring. It's like, you know, when you do a lot of exercise after you finish, do you tend to be hungry? And I was like, yeah, you know, you're quite right right like if you've gone out for a really long walk somewhere or he's done something really hard or he was saying you know i've got a 15 year old son like he comes back he's starving he's like yeah you're really hungry he's like what do you do he's like oh like i eat lots of food and he said sort of bingo so that in a sense once again what a surprise i think his message was your body tends to tell you when you need this and that you know for most people probably your hunger is going to help to to drive drive this do you think that's a would you agree with christopher i guess on this i would i mean we we always have to try to um use the best laboratory controlled experiments to understand

the fundamental mechanisms and then have some level of pragmatism to how that rolls out into real life. So if you do increase the protein requirement of the muscle by exercising it, the muscle is going to be quite good at extracting that protein requirements from subsequent meals. It's not going to say, if I don't get it in the next half an hour, I'm going to stop using it. We talked a lot about muscles. We actually had a lot of questions from our listeners about the impact of menopause, so maybe perimenopause, postmenopause. Is protein also important for things like bone health, or is it very much focused on muscles, this conversation? No, it's important for bone health as well. And that's been a relatively controversial topic over the years. There was a narrative suggesting that higher protein diets to

support exercise may be less good for bone health. I think that's largely being debunked in terms of it's probably quite good for bone health. There's less data on bone health. One of the reasons there's so much on muscle tissue and exercise, A, because people care about muscle tissue because it's got such a key role in how your muscle tissue adapts, ultimately dictates the function that you want to do with it, but also because it's slightly easier to investigate. People forget that a lot of what we know about muscle metabolism is because we can directly sample muscle tissue from healthy people and we can measure all these things. Sample means cut out, does it?

It does. Lovely. But you can't sample my muscle tissue today. Thank you, Ben. No problem. I didn't bring a needle with me today to do it. Okay, good. Maybe next time. If you told me it was a clinical study, I'd let you do it anyway. I'm like a total, I'm totally up for every clinical study, but okay. But it is harder to do those things in, for instance, bone tissue or other tissues where it is more invasive to sample those. Got it.

But protein is, just to understand, because I think I sort of grew up with the idea of bone as somehow being like sort of inert, almost stone-like substance. But protein plays a role in bone health? Yeah, it's one of the things that's been realized relatively recently, or not realized, but appreciated, is the turnover rates of protein in bone, heart, even brain is always occurring. And it's still extracting amino acids, the building blocks of protein from the protein in our diet. So we're not just replacing muscle proteins with what we eat, we are replacing proteins across all these other organ tissues as well. And they also similarly respond to exercise.

We know less about how they adapt to every meal than we do muscle tissue, but we do know that they're influencing it, absolutely. And this helps explain why a healthy diet is important for bone health. We're particularly talking here, obviously, about menopause, but more broadly. Absolutely. Last question before we want to talk more about how this ties into aging and things like this, but is there a maximum amount of protein that actually our bodies can absorb, or is this a myth? This was one of the real hot topics maybe 10, 15 years ago,

and there were some really nice studies that kind of, I think, do give us some quite clear answers. And sometimes I think it's about how you phrase the question. If you say, is there a maximum amount of protein that we can absorb? Probably not. We will absorb everything that goes into the gut to some extent. It might just take longer. It might be slower if we have a lot. But how much we absorb versus how much we use

metabolically is a different question. So if we imagine that we take in a very large meal containing, let's say we have a really large steak, lots of protein in it, it might sit for various levels of the gut for several hours, but ultimately will absorb a set amount of the amino acids in that protein. And we will use those for metabolism over time. Another way of asking it is, is there a maximal amount of protein that we can use to stimulate muscle growth, for example? And that became something that was then investigated with sort of systematic approaches using state-of-the-art techniques to look at muscle tissue itself. So there's a study from Stu Phillips' lab, I forget the date now, but Dan Moore was the first author, and he looked at gradations of ingestion of egg protein. And what he did there

is, I think it was 20 grams, you could see there was a maximal response of muscle tissue in terms of this building up, this synthesis response we're're talking about and this was either at rest or post-exercise if you had 40 grams of protein you've still absorbed it it's just not being used to build up muscle tissue you've reached a plateau there and actually what you use then is more of the protein is just oxidized it's used as energy and and generally disposed of so just like extra calories extra calories exactly and not disposed of might mean just eventually stored as fat in your body as well, right? Like just not necessarily disposed of, which is what I discovered from Christopher a few months ago. Absolutely.

Ultimately, if you're having excess calories of any macronutrient, you've only really got one place to store them and that's in fat tissue. Protein can only really be stored in very, very minute amounts in this synthetic response of tissues after eating. And there's no other way of storing protein. So yes, disposed of. That study has also been repeated several times with different proteins. And it's a similar story, which is once you go above 20 grams in a meal, you're not getting

any extra muscle building response. The only caveat I would give to that is there's one study recently that showed that you might be able to use a little bit more for muscle building if some of these laboratory-based experiments that only use single leg exercise are using whole body exercise, where all of a sudden you're increasing the protein demands of the muscle across the body rather than just one leg. So there is some suggestion there that it might be a little bit higher than 20, but there will always be a maximal limit that we can use.

And can we talk about those numbers just for a minute? Because we had so many questions around this. And what I understood from this podcast we did a few months ago is there's a sort of recommended daily amount of protein. I think it was about 0.8 grams per kilogram of body weight. And that for most people, this was probably sufficient is that your view also but then how does that change for people who are maybe doing a lot of exercise really trying to build up muscle and how does that fit with the amount per meal you just sort of mentioned

this sort of 20 grams per meal because it seems like well if you're eating three meals a day that's sort of capping you at 60 that still feels way less than when i went to the gym and spoke to my trainer i think he was like more like two grams per kilogram or something that i was supposed to be eating in order to like maximize the benefit of this new amazing buff jonathan which if you see me you see it hasn't really entirely delivered so i think there's lots of questions. And I think this pushes people to eat a lot of foods as a result. So I think it's really important. And what are the facts? What does the science say?

Okay. So the 0.8 grams per kilogram body mass is a recommended daily amount. Without going into too much detail on that, that's broadly the amount we should eat to remain in something called nitrogen balance. So that's taking in a similar amount of nitrogen, which is the only place we take that in is within protein and excreting the same amount of nitrogen. So that's balance. So basically retaining our tissue as it is. That's derived from nitrogen balance studies, which is by necessity a whole body level. So it's encompassing all the tissues of our body.

And it's by definition, encompassing the majority of the population. So it's a very good benchmark amount that we should have to remain healthy. The difference there when we're talking about a recommended daily amount for health is it's kind of a minimum requirement to maintain health. When we're talking about exercise, what we're generally talking about is trying to optimize something like an adaptive response to exercise. An adaptive response means? With the most obvious example to use here is if, the example you just said, you're going to the gym, the trainer's trying to give you exercises to try and increase your muscle mass. So you're saying you need to increase your protein. That's a different question to whether or not this is

protein for health, this is trying to, or general health across the body the body this is will having more protein increase the amount of muscle tissue i have so that's really a slightly different question it's almost like an optimal versus a minimal requirement for health when we do this then we can look at whether or not broadly just consuming more protein is beneficial even before we look at the amount per meal or the timing. And the answer to that is, I'll perhaps start with the answer and then explain where we've come to this answer is, it does, having more than the RDA does increase the amount of muscle mass we can gain while training, but it's a relatively small amount. The majority of muscle that we gain is a direct result of the exercise and adequate protein in our diet.

We can add a little bit on top of that by actually increasing our protein intake. So the first part of that message is, if you're not training hard at the gym, your RDA is just fine, I think you're saying. If you are training hard, or it doesn't have to be just at the gym, I guess, like you could be out walking miles, so you want to get yourself stronger and fitter. I think you're saying you probably do want to be higher. How much higher? Because I think this is where a lot of us have been told these numbers, which are hugely higher, causing us to worry about having enough protein. Give us the truth, Ben. I'll start with the resistance training because there's some clearer answers on this front.

Some nice systematic review and meta-analysis type approaches that encompass lots of the studies in this field have generally arrived at a fairly similar conclusion, which is always reassuring in science when different groups come to the same conclusion. But really, if you push up from that 0.8 grams per kilogram body mass per day up to 1 or 1.2 all the way up to 1.6, you generally get slightly better outcomes in terms of gains of muscle mass and strength. Beyond 1.6, there seems to be a plateau where no additional benefits are available. A kind of breakpoint analysis will show you that. So really, I would say you can find a lot of recent papers now that will generally agree that about 1.6 grams per kilo is going to

give you the maximal benefit that you can expect from additional protein in the diet on top of training per se. The answer when we want to actually refer to something that's different than just gaining muscle, but for instance, what we discussed before, the reconditioning of muscle tissue with, for instance, more endurance-based exercise is a little bit more complicated. Similar to lots of things, endurance athletes, they use a lot of energy, so they consume more food, so they automatically consume more protein. It may well be that it's rather similar. The nitrogen balance studies do suggest that endurance exercise pushes up the requirements of protein close to 1.6 or even higher, just because of the additional caloric use. You still use some of that protein while doing

exercise. But I think this is quite an exciting area that's going on now because there's a lot of people using more modern approaches to actually look at whether or not the requirement for protein-during exercise and the requirement of protein to push adaptations associated with endurance exercise in the muscle, making it more energy efficient, can actually benefit from that additional protein. I would say that's a less clear answer than I can give you on the 1.6 for resistance training. So I think that's a really important point. This came up in a previous

podcast. I think it was looking at American and British data and suggested, you know, the RD8, like the recommended amount is this 0.8 per kilo. Actually actually on average, everybody is eating double this of protein already. So that would sort of take you to this 1.6 level, which would suggest that, you know, when I went into the gym, I'm probably already eating all the protein I need for actually building muscles, nevermind holding it still. Is that right? Do you think people need to worry about adding more protein? Take me as sort of as this example, know in your mid 40s doing this i think the vast majority probably don't need to worry if they're undertaking exercise and they're eating sufficient food they're probably eating sufficient protein they will be above the 0.8 what we're really talking about is trying to maximize adaptations for people

who are really concerned with squeezing out that that last percentage of every exercise bout. And that really brings us to when it might be advantageous because eating 1.4 or 1.5 grams per kilo is not too difficult if you're eating two and a half, 3000 calories, which a lot of young exercises already are. It is a lot harder if you're trying to, for instance, reduce the calories that you're consuming in your diet for weight loss, or you can't consume as many calories because you've got a reduced appetite or illness or inactivity, because then your overall energy intake decreases, which of course then resultantly means your protein intake decreases without particular attention to that macronutrient. And can we talk about that? Because I think we had a lot of questions around sort of aging. People,

I think, very interested, right, around sort of aging people, I think very interested in maintaining that health span that you were talking about at the beginning. And I think we all know that sort of our muscle mass, the amount of muscles tends to decline as we get older to the point when we've had guests here talking about, you just can't get out of your chair. And at that point, all these bad health things happen. I guess two questions. Why does the muscles decline? Because that doesn't seem obvious. And you mentioned at the beginning that older people may find it more difficult to get protein

in as well. So could you just explain what's going on there? And I guess, therefore, as we're thinking about either ourselves or maybe relatives how should we thinking about nutrition and protein as we get you know later into our lives i think i think aging is probably a really interesting model to discuss when some of the aspects that we've perhaps said are take care of themselves with protein and younger people is far more important to consider. So we lose muscle tissue as we get older. We generally call this sarcopenia. A nice way of thinking about sarcopenia, and it goes back to the quality of muscle that we

discussed earlier, is on a population basis, we tend to remain a relatively stable weight as we get older. I feel like despite all my best efforts, we all naturally put on a little bit of weight over time. You don't see that, Ben? It fluctuates over time. But if you look across decades, for instance, what the bigger factor is, what comprises the weight that we are. So we lose muscle tissue and gain fat tissue. So it's an undesirable shift in composition. And that's often called sarcopenic obesity. So you might get somebody that's not particularly, hasn't put on a lot of absolute weight, but they've actually put on a lot of fat, but they've lost the muscle. And this is what we talk about when we get less functional, less metabolically healthy,

because they've just got more fat to muscle ratio. There was a suggestion put forward by a paper from Cuthbertson, Mike Rennie's lab, to show that something called anabolic resistance to protein. So this was the idea that when we have a protein meal, as we get older, we don't respond quite as effectively to it as when we were younger. So the good way of viewing that would be if we have a piece of chicken and an older person, a younger person has it, more of that piece of chicken becomes the muscle tissue of the younger person than would be the case if it was the older person. So this is like a very slight reduction. It's not like I'm

suddenly only able to get half as much out of a protein bar or something as somebody who's 30. Exactly. It's a really insidious response. And it basically results in the kind of what we classically see as the frail older person in their 70s or 80s. That process probably started when they were more like 35 or 40. It's just happening much more slowly. And one reason that has been suggested is this anabolic resistance to protein intake. But the important question about that is whether or not there's anything that can be done about it. Because, of course, we all know that we're probably going to get frail as we get older.

Tell us the answer. Well, my answer is always, there is something we can do about it, because otherwise, which is what underpins how exercise and nutrition can ultimately help us live healthier lives. Regrettably, there is some inevitability about the decay of the human body with age. Ben looks very young, by the way, for those who listen on the podcast. So he says that, but it's very hard to feel he can really feel it in his heart because he's clearly evidence for the good exercise and the good nutrition. You'd have to verify that

with my wife, whether the nutrition is good at home or not. So some studies have demonstrated that an older person can simply consume more protein within a meal, and then they can actually increase their response to a protein intake. So we discussed before about 20 grams being a maximum for a kind of muscle building response in a younger individual. It's been shown a few times now that that is higher in older adults. So you could probably benefit from 25 or 30 grams of protein, whereas the younger person wouldn't benefit from it. And how, because there's two parts to this, I think, right? So one is that you may well just not be doing as much exercise as you're older than certainly you were probably when, you know, I'm thinking about my 15 year old who's kind of at this point where like, there's a lot of exercise in his day, which is already not true for me unless I make it happen.

And then there's also, I think you're saying, sort of declining appetite. So you're just eating less food. Is it a combination of the two that is leading to sort of this loss of muscle? And can you fix it just by eating more protein or do you have to lead with the more exercise and then the nutrition is on on top it's a great question i mean in some respects some people have tried to take the the real extreme stance of saying we don't decay because we get older we we decay because we we get less active because of course the two go hand in hand as you have just pointed out and we can certainly this anabolic resistance that i speak of which we can which we can detect just just in populations that are 30 years apart, we can detect in two, three or four days if we just immobilize the leg of a healthy individual.

So what I mean by that is if we measure the anabolic response, the muscle building response to a meal in a young, healthy individual who has walked around with one leg in a cast for a few days and the other leg not, so we isolate the variable of activity, nothing to do with age, we see anabolic resistance straight away in every individual we look at. And just to make sure that I've understood, anabolic resistance, I mean, like somehow the leg that was in this cast just can't use this protein successfully compared to the other leg that's still been walking around. Precisely. We actually showed a few years ago that from a meal of 20 grams of protein, 40% less was

used by the immobile leg compared to the mobile leg. So coming back, I guess, to my question, can you fix this just by eating more protein or really you need to exercise and the protein is secondary? The exercise still becomes paramount. So the other thing that an older person can do is perform a bout of exercise. And performing a bout of exercise basically sensitizes the muscle to the amino acids, the protein in the diet.

So it makes the muscle respond a little bit more youthfully, if you like. But we can also then go a broad picture back, look cross-sectionally at older people who are more active, older people who consume more protein, older people who do both. And we can say, yes, generally, these cohorts of older people lose muscle tissue at a slightly lower rate than those that don't exercise or consume sufficient protein. However, the regretful bit that I said at the beginning is they are still losing muscle tissue and if i try to pin you to the ground which i know scientists hate to do without really all the data and you were saying like i want to make sure that i don't have this muscle loss because it's really going to affect the health you were describing my brain and my heart and all the rest of it i mean is this 80 exercise and 20 making sure i'm getting enough protein? Is it 50, 50? How much of those

two should I be worrying about as I think now about my action? Somebody's listening and saying, what do I need to do? Is it to go and eat more chicken or is it to go for a walk? I would say it's 80% upwards on the physical activity side. We see that the consuming protein becomes less and less effective as we become less and less active. In fact, when we immobilize people, we struggle to pick up the benefits of protein. I'd love therefore to come on to sort of this question about where you get your protein. And I think that we're living currently in this environment where there's this enormous amount of advertising about ultra processed foods that have all of this protein. And I was thinking about those bars that say 10 grams of protein added or people thinking about, I need to have some sort of shake with

whey powder in it in order to get the protein that I need. I think everything that we've learned through this podcast makes me feel very negative about those sorts of foods, but they do have lots of protein in it, right? So very high levels compared to most foods. How would you think about them? There's an argument to say, if you want to get every single percent out of your workout at the more elite level, that it might make a difference. The exact protein that you have following exercise, you might get slightly more out of it. If we step back slightly and look at all the protein that we consume across a day, this tends to pale into insignificance compared to just

getting sufficient protein for your goals, whether that's training or whether that's living a healthy life as we get older. An important point of view there would be is the pragmatic view though, because we've just discussed older people maybe have a slightly increased requirement for protein for muscle health, but that's concomitant or in parallel with the idea that they might eat less or find it harder to eat more. So there's a role then for how much protein is just available in foods. So something like chicken, it might not just be that chicken protein is great or whey protein is great. It's just got quite a lot of protein in it. And if you want to get the same amount of protein from broccoli, you've got to eat a lot of broccoli to get that

same amount of protein. So there's a level of convenience and practicality to something like a supplement that might be far more important than the actual protein that happens to be in it, for example, being particularly magic. There's a bit on both sides there, Ben. Let's say I'm listening to this. I'm just thinking about my action to believe what I should do. Maybe take me as an example. So I'm going to the gym three times a week. I'm lifting some heavy weights. I'm told that's good for me to help maintain all the health things that you're describing. I've sort of came away from the last conversation that we had about protein thinking, I really don't need to worry about protein. That's not really a problem. I need to make sure that I'm eating a

really good, healthy diet and it's balanced and that's going to give me all that I need. And that therefore, you know, the sort of these protein shakes that I had when I first started doing this definitely don't make sense. Would you agree with that? Or are you actually saying, well, actually, maybe I need to worry a bit more if I'm doing that about whether I'm getting enough protein? No, I don't think you need to. I mean, if you take the example you give, let's take a real textbook example. You're exercising, you're working, you're using two and a half thousand calories a day, you're consuming two and a half thousand calories a day. The protein comprises 15 to 20% of that. You're probably getting sufficient protein. I suppose the situation changes.

If you're trying to cut down your calories, you want to have 1500 calories a day. You want sufficient protein to support the adaptations of the exercise, but you don't want excess calories. You'll then be seeking protein dense foods. Got it. This is like, I want to look incredibly buff for my next Hollywood movie. So I need to have all my muscles and like 7% body fat. That's your, I'm looking forward to being asked to be in that next Hollywood movie. So I need to have all my muscles and like 7% body fat. That's your, I'm looking forward

to being asked to be in that next Hollywood movie. Somehow I haven't had the invitation yet. It could be that, or it could also equivalently just be wanting to lose weight for health reasons, but wanting to retain some muscle tissue

for health reasons as well. So there's an element there of just wanting to make sure protein doesn't drop at the same time as calories do drop. Things like protein shakes or protein-containing foods become just a feasible strategy for not having a full meal, but having the same protein. It's not necessary if you're having sufficient protein. The additional gains from that are probably so small as if they are there that

most people wouldn't notice't notice i think the interesting element there is if you want to replace something like meat proteins with non-meat proteins i'd love to talk about because i think you know one side is the ultra processed i don't think many people listening to all of these podcasts will be very excited about that lots of people are really interested to understand plant versus animal protein you You're talking about whey, right? That comes ultimately from dairy, doesn't it? So what does the science say about plant versus animal? We had lots of questions around this. Again, if I go back to the traditional literature, some very nice studies, these laboratory controlled studies that have looked at the

hours following exercise compared originally the muscle building following a bout of exercise in conjunction with the consumption of dairy proteins, whey and casein, and generally compared that to soy protein. Soy protein was generally lower in some of the essential amino acids that we think are important in muscle building. And in line with that, they showed a lower muscle building response. Largely following these studies there was the narrative therefore that if you want to go to a gym and build as much muscle as possible then you've got to stick with animal proteins and I think that we've probably moved from that narrative now

in the current literature because we now have studies on more divergent protein sources from plant origin. So rather than just eating this one plant from protein, you're now saying like lots of different plants with lots of different mixes of amino acids. Because one of the main criticisms of a plant protein would be that it might be lower, you can use the word deficient, but at least lower in key amino acids. That's definitely true. The question is how consequential that is when we think that we actually, multiple plant-based proteins from different sources, complementary proteins, if we again, coming back to the idea that we are

getting sufficient protein. The studies more recently now looking at that more consequential question, which is if I'm getting sufficient protein and training, does it matter where it comes from? Generally show, no, it doesn't matter. We recently published a paper this year demonstrating that people training five times a week, very, very hard, intense training for 10 weeks, they gained about two and a half kilos of muscle tissue. Half of them were obtaining most of their protein from animal sources, half from plant-based sources. There was no difference at all. And that was the goal of the study was to drive the biggest adaption to the biggest amount of muscle tissue we could gain in a relatively short period of time as we could and give them the optimal diet with animal protein and everything that people say, and then see if that was impaired, if we made

them virtually exclusively vegan for that time and it didn't impair it. So that's how, and it's also in line with papers from other groups such that the only caveat I would say there is in all the papers so far, that is people having sufficient protein. And assuming, because I think, you know, we talked a bit about some of this sort of particular issues around aging, but we all know that most people's issue is not that they're not eating enough food, right? It's that they're eating too much of the wrong sorts of food because that's the environment we live in. Was there much of the wrong sorts of food because that's the environment we live in. Was there anything special about the sorts of plants that they were eating in this

study that you did? Yeah, I mean, we hinged that to using fungal-derived proteins, mycoproteins, mainly because we'd used those proteins before and we demonstrated that they were under the more controlled laboratory environments that we've discussed. They were as anabolic as animal protein. So they're a kind of controlled agriculture, really, with benefits in terms of sustainability in the same way that people want benefits on the plant based proteins and these other various aspects. The caveat I always give to this work is it's just a bit harder to feed somebody on relatively high protein diets when you take away animal proteins. When we talked earlier about easily consuming 1.2, 1.4 grams, if you actually

look at the diet diaries of people that do that, a big proportion is coming from dairy and meat. So when you do take those out, you perhaps have to be a little bit more cognizant of where that's going to come from and then selecting protein sources that can actually fulfill that. That makes a lot of sense. And I think there's a lot of people listening who may have really cut back meat in their diet, but are actually still having quite a bit of dairy. And that definitely describes my diet, for example. And it's clearly what you're saying, that's really quite easy. If you go to being vegan and you're cutting out all of dairy, then I think it's sort of raising the bar and making sure you're having this healthy, balanced diet. And I know that there'll be lots of people listening saying, I have this fantastic diet doing that.

You sort of have to be a bit more thoughtful, am I right in saying that, in order to make sure you're getting the right protein? I think so. I think it's kind of inescapable. You've got to be more thoughtful. But I think what we and others have shown in those kind of papers is it's eminently achievable. Amazing. We were following up on exactly what sort of fermented mushrooms you can have, because I think if Tim was, Tim's going to be listening, he's like, you know, that's, it's got all the things he's going to love, plants, fermentation, all the rest of it. Ben, there's many more things that I could ask, but I think we're definitely at time. I'd love to try and do a quick summary of what we covered and please, you know,

let me know if I've got anything wrong as I run through it, if that's okay. Absolutely. Brilliant. So I think we started by just saying exercise is incredibly important. And there's just this new emerging evidence about how it affects all parts of our health. I was particularly excited to hear about this, that it may even affect your risk of dementia. It's not just about your cardiovascular health and things like this. Muscles are a really big part of this. And an interesting, there's such a thing as a healthy or an unhealthy muscle. It's not just how big it is, which was completely news to me. And if you can get to these healthier muscles, actually, they're really going to support you by, for

example, reducing these blood sugar spikes, being able to sort of balance your body out more. They're constantly replacing themselves. I think you said like one to 2% of the muscle is basically turning over. And if we exercise, we actually increase that. So that's even more. So we need to keep eating this protein just to maintain our muscles. And then we need to eat even more if we want to get more muscle, which will probably support that exercise and the health. Most people don't need to worry about having enough protein, that the 0.8 grams per kilogram is sort of what you need for balance. Now, if you're trying to put on more weight, and that could be like my 15-year-old

son who just frankly is putting on that because he's growing, but also wants to get stronger, or somebody saying, you know, I really need to get fitter. Maybe I'm the person you described who's seen their weight stay fairly stable, but actually over time that, you know, the muscle has gone down and the fat has gone up, then it needs to be higher. And you said, it does depend the sort of exercise you're doing. You said for resistance training. So this is sort of like the weights and the strength that I think we've spoken with Javier and others have been really great for your health. Probably 1.6 grams per kilo is really the top. So once you go above that, it doesn't matter anymore.

Might be a bit higher for endurance, not sure. And again, most people are getting this. And I think the two people that you described you need to think about is one is as you're getting older and getting relatively late, I think, in your life you're describing, you'll find it harder to absorb this protein. You may also just be eating smaller amounts. So it can be a problem to look at. And yet in all of these cases, fundamentally, it's the exercise is 80% of this.

The nutrition is the 20% that you're putting around in terms of the muscle control and all the rest of it. Then final couple of things, you definitely killed a few myths. Don't worry. There's this anabolic window of when you eat after exercising. Don't worry about it. You know, it doesn't matter if you have to delay. And I was just thinking about, you know, our ancestors going out for a hunt and killing

an antelope and thinking, yeah, they probably didn't like eat the antelope straight after killing it, did they? They worked out harder than I've ever done. And presumably they went back and they made a fire and they cooked it. So it sort of makes sense that actually we're designed to be able to wait. And then finally, we talked about what sort of food you should eat. You don't need to eat these protein shakes and things like this. And that actually, interestingly, you've just done this brand new study that showed when you had people exercising really hard and

putting on a lot of muscle, actually, you could feed them an entirely plant-based diet and they were able to put on the same very high amount of muscle as animal. With the proviso that if you were eating no dairy, it probably is a bit harder in that situation to get all of the protein that you need. So you can get it to work as a vegan, but it's clearly like a higher bar than if you're having some cheese or whatever it is in your diet,

where I think you were saying it was pretty easy. A remarkably precise and concise summary. I wish I could do it so succinctly. Well, that's because I don't understand anything more than what you've just described to me. Ben, I thought that was fantastic. Thank you so much for coming in. I am sure we will have a whole host of follow-on questions after this. So I hope we can get you back again in the future. It's been a pleasure. Thank you very much. Wonderful. Thank you, Ben. Bye-bye.

Goodbye. Thank you, Ben, for joining me on Zoe's Science and Nutrition today. If you want to understand how to support your body with the best foods for whatever exercise you're doing, then you may want to try Zoe's personalized nutrition program to improve your health. You can get 10% off by going to joinzoe.com slash podcast. As always, I'm your host, Jonathan Wolfe. Zoe Science and Nutrition is produced by

Yellow Hewins Martin, Richard Willan, and Alex Jones here at Zoe. See you next time.