No. 1 protein expert: Are you eating enough? with Prof. Stuart Phillips and Dr. Federica Amati

Are you eating enough protein? This is probably a question you’ve asked yourself.

With “high protein” labels on almost every type of food product you can imagine, it’s easy to worry — maybe I do need to eat more protein?

Stuart is a professor in the Kinesiology Department at McMaster University. He’s the author of more than 400 scientific papers, many focusing on protein and muscle health, particularly during aging. 

With so much confusion around this topic, especially in the context of fitness and aging, this episode will provide clear, evidence-based answers from one of the world’s leading scientists on the topic to help listeners make smarter nutrition choices.

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Jonathan Wolf: Stuart, thank you for joining me today. 

Professor Stuart Phillips: It's a pleasure, Jonathan. Thanks for having me. 

Jonathan Wolf: Federica, thanks for being here. 

Dr Federica Amati: I'm so excited about today. Jonathan, can't wait. 

Jonathan Wolf: I think we're all excited about this one. 

First, we have to get through our traditional round of quick-fire questions. And Stuart, I've heard that you have listened to this podcast so you know what's coming.

Professor Stuart Phillips: Sure. 

Jonathan Wolf: We've designed this to be really difficult for scientists. You're ready to give it a go? 

Professor Stuart Phillips: Yeah, go for it. 

Jonathan Wolf: Brilliant. Stuart, is the protein that we consume mostly used for our muscles? 

Professor Stuart Phillips: No. 

Jonathan Wolf: Federica, are most of us deficient in protein? 

Dr Federica Amati: Not most of us, but some groups are at risk. 

Jonathan Wolf: Stuart, can protein help keep you healthy as you age?

Professor Stuart Phillips: Yes.

Jonathan Wolf: Federica, could some people benefit from protein supplements? 

Dr Federica Amati: Yes, but quality is important. 

Jonathan Wolf: And back to Stuart, does it matter when you eat protein? 

Professor Stuart Phillips: Maybe. 

Jonathan Wolf: And finally, Stuart, you've been researching protein for decades. Is there anything that you've changed your mind on as new data has emerged? 

Professor Stuart Phillips: There's lots of things I've changed my mind on, but I think the big one is that plant derived or plant-based protein is not inferior to animal-based protein in terms of supporting health and definitely muscles.

Jonathan Wolf: I think all of those quick-fire answers are super interesting, and that's partly because I know that we get an enormous number of questions about protein from our listeners. 

I think that's partly because there's enormous amount of conflicting advice online. But it's also partly because big food companies have started to plaster their products with labels saying high in protein, and as a result, lots of people are saying, Well, so I guess I'm deficient in protein, am I getting enough? 

So I'm incredibly excited to have both of you on here to hopefully clear up a lot of questions. Stuart, you are one of the world's leading researchers on protein with hundreds of peer reviewed papers on the subject. 

And Federica, you've been leading ZOE's own position on protein, which I know incorporates a lot of Stuart's research in order to provide personalized protein guidance to ZOE members. So I can't think of two better people to hopefully clear up some of this confusion. 

But before we talk about exactly how much, Stuart, could you actually help to explain why protein matters at all? 

Professor Stuart Phillips: Yeah, I mean, the clear distinction I like to make is that for carbohydrates and fats, they're fuel for the most part. There's a small requirement for fat to be a structural element of cells in our body.

But protein is the structural component of everything. It's skin, it's bones, it's your heart, it's your lungs. And, clearly it's your muscle, but it's part of your brain too. 

So, it's a substrate. It can also be burned as fuel, although not very much. So that's, I think, the key part that distinguishes it from the other two macronutrients. 

Jonathan Wolf: And can you help us to understand a little bit more? Why do I need to get it in food? What happens when I eat it? Where does it go? 

Professor Stuart Phillips: Yeah, sure. So protein is made up of building blocks, and we call these building blocks amino acids.

And the amino part comes from the fact that protein contains nitrogen. It's the essential nuclide that differentiates it from carbohydrates and fats, which are basically carbons, hydrogens, and oxygens. 

There are 20 different amino acids and we require, we need to get them from our diet, nine of them. And of those nine essential, we call them amino acids, there are groups that have various functions, but we can produce the rest.

So the need for protein is really the need for those essential amino acids, which are degraded and excreted in urine, hair, nails, your feces. 

And so our requirement for protein is really about replacing essential amino acids that are lost. 

Dr Federica Amati: Yeah, and I love to think of amino acids essentially as building blocks, as you said.

And it's amazing when you see the way the amino acids then connect and fold, makes proteins. Those then, as Stuart said, go to form skin, hair, nails. Also, it's an essential part of your immune system. 

Your immune system relies on protein to create immunoglobulins to get ready for inflammation or to get rid of an infection. So a really important thing. 

And this relationship between essential and non-essential amino acids is also important because our liver can use essential amino acids, like taking Lego bricks apart, and then build up the non-essential ones. 

So if you're getting enough variety of amino acids in your diet, apart from the essential ones, which you have to get through food, your liver is able to build the others and then make any protein need from that, which is really cool. The liver is super smart. It's a very clever organ.

Jonathan Wolf: I'm just thinking about all the parties at your house as you're watching YouTube and protein folding. I don’t know whether I'm going to quite be able to convince my family that that's Saturday night entertainment. 

Probably Stuart at your house, this is Saturday night entertainment. 

Professor Stuart Phillips: It used to be when my boys were young enough to appreciate Lego blocks, et cetera, but not so much anymore. 

Jonathan Wolf: Brilliant. So there are 20 of these different amino acids. These are sort of the Lego bricks that I use to build up the proteins for everything inside me. And as a human being, I can't make all of those from scratch. 

So, nine of those Lego bricks I need to take in, but the other 11 I can make myself. 

Now when I think of protein. I was thinking about this, last night, I immediately think of my 17-year-old son and he's like, well, I need to eat steak so I can put on more muscle at the gym. That is the link for him, it's totally clear. 

Everything that he's seen on his social media channels are all about, as a 17 year boy, how do you put on more muscle? And it's very exciting for him as well. Because the truth is that I go to the gym and I try really hard not to lose muscle. He goes to the gym and the next day it's just there. It's totally unfair. 

I'm sure there'll be some listeners who can understand that, but I know that in your research you are not just focused on sort of young people. People looking to weight lift or look beautiful. But actually you've done a lot of research on protein in older adults.

Could you help to explain why protein is important for health and quality of life as we age? Not just if I want to put more muscle on. 

Professor Stuart Phillips: Yeah, I mean, I think it would be fair to say over the 28 years that I've been at McMaster University, I started out, and we just looked at young people. We were interested in making their muscles bigger. So much like your son or university-age students. 

We learned a lot about what we can do in terms of protein. But the key stimulus for growing muscle, if you're younger, or if you're older, about preventing the loss, and I'm squarely in that category as well, is to lift weights. So resistance exercise, or loading, is the most important part. 

When you're a kid and you're growing, you're under the influence of lots of growth factors. Linear height and then broadened chest, and all these sorts of things, which your son is experiencing. And the fact that he's lifting in the gym, two thumbs up.

When you're older, of course, that growth stimulus is gone. And at a certain point, and it's probably depressing to mention, this is probably for most people, it's in their thirties, they begin to slowly lose muscle. 

This age-related loss of muscle is a condition, if it's problematic, that we call sarcopenia. So, time marches on. Research becomes me-search because I'm interested in what's happening to me.

And I also direct a center where we have 500 community members coming in essentially to exercise. The average age of them is about 72. So, you know, I'm talking to these folks, why are you here? Why are you exercising? Well, I've heard it's important and et cetera, and this story goes on. 

So, lots of important benefits are associated with hanging on to muscle. But from the protein standpoint, supporting that lack of muscle loss and supporting all of the other physiological processes that Federica mentioned about protein-requiring processes that are important in older people, too.

Dr Federica Amati: Yeah, it's so important in older age to have functional ability and to be functionally able. You have to be able to get out of your chair, get out of bed by yourself, and musculoskeletal mass is essential. 

So how healthy your bones and your muscles are, and especially the muscles that help the skeleton get up. So not so much the like good looking muscles, but the functional muscles, they're the ones that we want to maintain.

Because as we get older, that's where you really see the difference between being able to live independently and having to need help to do sort of normal daily routine. 

So I think this is where a lot of the interest has come from in how do we maintain this functional ability in older adults. Musculoskeletal mass is super important for that.

Jonathan Wolf: And so is protein and muscles only about continuing to have strong enough muscles to be able to get out of your chair or to be able to get out of bed or to not fall over? Or does it play any other role? 

I'm asking Federica because you've talked about, for example, your immune system and…

Dr Federica Amati: As Stuart mentioned, we can't store protein. So, whereas with energy, we store it in our muscle tissue, we also store it in our liver. We store it as fat in our fat cells. So we have lots of lovely energy stores to tap into when we need them. 

But if you don't have enough protein in your diet, then essentially, we can't really get it from anywhere apart from breaking down our muscles to get that protein. 

We do that because the immune system needs protein because other functions, enzymes, which catalyze all of the reactions in your body, are proteins. So what happens is your body then starts to draw protein from your muscles to help with the other processes. 

Well, you see this a lot, Jonathan, like thinking about the life course, in low-income countries where there isn't access to food. The biggest killer for children under five is protein malnutrition, because our bodies cannot cope without enough protein. 

So when we think about why we need to be aware of the importance of protein, it's because it's involved in so many processes. Because of that, our body's amazing at absorbing it from food, by the way.

We're super efficient at absorbing protein from the small intestine and making the most of everything we eat. It's essentially a really important part of health, generally. 

Jonathan Wolf: If I'm not immediately getting it from food, I'm going to sort of strip it out of my muscles in order to carry out all of these critical things, like fight my cold or whatever it is.

So if I'm not getting that protein, then basically I'm going to strip down those muscles. And so this is one of the reasons that I might lose muscle over time if I'm not supporting it? 

Dr Federica Amati: Yes. And you see examples of this in two big groups. 

So one is people who have rapid weight loss, GLP-1 receptor agonists.

If we don't support people that take these drugs with exercise and correct nutrition, their body will use muscle to get protein. 

The other big group is cancer patients. So, patients who are undergoing chemotherapy. Cancer is a very metabolically active disease, and so it will get protein to support the immune system from your muscles.

This is called cancer cachexia. So this loss of muscle mass in cancer patients it's a big problem actually. It's a big predictor of survival for patients. 

Professor Stuart Phillips: It's like muscle is a labile reserve of amino acids and protein. And despite what people think about its importance, as Federica mentioned, it is the tissue that essentially will give up its amino acids for more critical processes.

There's a concept in aging, and this concept of muscle loss and sarcopenia, that muscle is sort of like a functional reserve. So in times of being challenged, whether you're sick or… during COVID was a great example when older people were hospitalized, and you know, it was a real struggle to survive.

And as Federica mentioned, skeletal muscle in those times is a particularly important organ. And almost the more you have of it going in there, the better your odds of survival are. 

Jonathan Wolf: It's funny, I'm completely re-imagining this that in a way I hadn't understood before. 

Because I think everybody listening probably is very familiar with the idea that the fat on their body is a store of energy. Right? We all know that if you haven't eaten any food, then you know that, in fact, that's where you are getting supported.

We know that human beings can live for a long time without food. As long as they're getting water. But we know that you lose fat and weight. 

I had never understood before that I could think about my muscles not only as mechanisms to move around with, but also, you're sort of saying it's the only place I can store this protein from one day to the next.

Professor Stuart Phillips: Yeah. I mean, I think that that's the odd part about protein that people maybe fail to recognize, is that we're very good at storing fat, almost an endless capacity, too good unfortunately.

We have limited capacity to store carbohydrate, but our liver and our muscles are two great sites where we do store carbohydrate. But there's nowhere to put protein, and sort of stock it away and use it at a later time.

So you either ingest it and use it, or you pull the nitrogen off, you make urea, ammonia, you excrete that mostly in the urine, and then the rest of the carbon skeleton that's left over you burn it as fuel. Or sometimes you can make it into glucose. 

I like to say, if you're stuck on a desert island and you had no protein, you wouldn't last long. But we can live with a minimal amount of carbohydrate and fat, as long as we have some protein. We won't be super happy, but we'll survive. 

Jonathan Wolf: Can I just ask for a second about that conversion of protein question because that came up a lot as well. Because we're now surrounded by products that say ‘high in protein’, ‘added protein’ and they're often on very highly processed food.

The argument basically is, well, there used to be fats and sugars in this, but now I've got protein, and so this is presented as it's all a win. 

But I think I just heard you say that if I eat more protein than I need, it can end up getting burned and used as calories. Could you just explain that for a second?

Professor Stuart Phillips: The seventies and eighties were characterized by fat was bad, carbs were good. And so we took fats out of a lot of foods, and we created very carb-heavy and in a lot of situations, replaced it with sugar. It was a true disservice to the food supply system. 

Then it was almost like it sort of swung back, and all of a sudden, fat was okay, and even saturated fat was okay. So the keto diet reemerged almost like a phoenix.

And now there's been a bit of a push, and I'm sure we'll talk about it, about the recommended dietary allowance in North America, the recommended nutrient intake in the U.K. Lots of different recommendations are probably too low, in my opinion, on a few others.

And so the pendulum becomes, well, we need to get protein because we're not getting enough. But that's not the message. It's actually, you know, a lot of people are getting more than enough. But maybe there are more people than we thought who aren't quite making it. 

So now the pendulum swung the other way. And you, as you point out, Jonathan, I think we've overcooked it, the message a little bit. And we've got products that, you know, protein water is the greatest example of… 

Dr Federica Amati: I like protein ice cream. Two-thirds of a tub for 10 grams of protein. It's awesome.

Professor Stuart Phillips: Yeah. Well, it's a pretty good ice-cream-to-protein ratio. But yeah, it's odd to see protein appearing in places where I don't think it has any business belonging because nobody's truly, in our societies, deficient in protein. 

There may be a few people who are just a little bit under what I think is the recommended intake, but I certainly don't think that it needs to be put into a lot of the foods where it's appearing.

Jonathan Wolf: Thank you, Stuart. 

And if I come back to this question about what happens if I'm taking more protein than I'm going to use right now. Because I had assumed that basically if I didn't need it, it was just coming straight back out the other side at no cost. 

But I think I just heard you say something else.

Professor Stuart Phillips: Yeah. So I think that there are some nuances in here. 

So the key point is that the nitrogen is pulled off of the protein structure and we make urea for the most part and ammonia, and that's excreted for the most part in our urine. 

So people say, Oh, you pee protein out. It's not really that you pee the protein out, you pee the nitrogen out. But once you've taken the nitrogen off of the amino acid, it ceases to be an amino acid and you either burn it, it's oxidized, so it yields energy or you can, in occasions you can turn it into glucose.

I think that it's true, however, to say that the efficiency that we do that with is not particularly good. So, as opposed to carbohydrates and fats, which we are very efficient at burning, we're not quite as good at burning amino acids.

So it's not that it's completely inert; you don't use it. You can, but maybe not with the same efficiency as carbohydrates and fats. 

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Jonathan Wolf: And I think that means it's not zero calorie, though, from that perspective. I just want to make sure this is clear. 

Professor Stuart Phillips: Protein is four calories per gram, kilocalories per gram, just like carbohydrates are with plus or minus a little bit. 

So yeah, of course it's energy. And when we look at everybody's dietary intake, it's not like protein; we sum it all up, and we just put a big zero on the bottom. For every gram, it's four kilocalories worth of energy as well. 

Jonathan Wolf: I think you are saying that seems totally obvious, and I was completely shocked because I think the way that it's presented is more like a vitamin. 

It's like, Hey, it doesn't count. You can get more of this thing you really need, as opposed to, by the way, if you're not going to use it up because you're not doing enough exercise today, then your body as usual, is going to figure out very efficiently how to burn it and therefore your total calories in the day is up. 

Ultimately, you know, if you are like many of us, just fighting not to put on weight, it's not going to be your friend, is it?

Professor Stuart Phillips: I think that there's a little bit of a nuance to that message.

We're not quite as good at burning protein as we are at burning carbohydrates and fats, but it's certainly not a free pass. In other words, if you overconsume protein, you are overconsuming energy. 

The hard part is to figure out do you actually gain fat. And, I know you've had Christopher Gardner on here, he's a good friend and a colleague, but I kind of surprised Christopher with a paper showing that if people consume more protein, they tend to gain a little bit of muscle, not a lot, and they don't gain as much fat as you might think. They still will put on weight, but not as much as you might think. 

I think that that's the sort of, Oh, you can eat as much protein as you want, it's not a problem. The answer is, like the answer to most interesting question is, it depends. 

Jonathan Wolf: What I'm understanding now is protein is definitely more than just building my son's big muscles. That we need it in order to live and function for every part of our body. It's also really important in order to live these long and healthy lives. 

I think this then brings us onto that key question that all of our listeners had,  how much, and I think you've already mentioned, right? There's a lot of debate on this topic now, Stuart. 

You've published hundreds of papers around protein, so I'd love to get your view, and you can maybe explain how that's contrasted with what you described about sort of historical recommended daily amounts.

Maybe just starting with healthy adults, what are your recommendations for protein intake? 

Professor Stuart Phillips: Sure. I think the beginning point for this is to talk about what we call in North America, it's the recommended dietary allowance or the RDA, in the U.K. recommended nutrient intake. It's usually about 0.8 grams of protein per kilogram of body weight.

Everybody wants to know, you know, is that ideal body weight? It's just per kilogram of body weight. From my perspective, I think that's a little bit too low. I think it should be closer to about one, maybe as high as 1.2 for older people. 

But I do think that the benefits of protein probably stop a lot sooner than a lot of people are making out. 

When you were first born as an infant in the first year of life, you doubled your body weight, and what do you think your protein intake was to support that? 

Jonathan Wolf: I'm assuming enormous amounts of protein at this point.

Professor Stuart Phillips: But remember, you're very small, right? That's true. So grams per kilo. It's actually, it's sort of about 1.2, 1.5, something like that.

So at the time of your life that you experienced the biggest and best growth you ever had, you did it with a pretty low protein intake. 

Jonathan Wolf: Is that breast milk that you're describing to us? 

Professor Stuart Phillips: Yeah, exactly. Nature's got it, right? 

Jonathan Wolf: That's a fascinating way to start with it. 

Some of our listeners won't realize, but this is a really charged debate. So if you're really into nutrition science and you talk to a lot of people, this is one of those areas where people get really worked up about this number. 

I feel that there will be a set of people listening to this and saying, Oh, but those numbers, they're clearly too low.  

I think about my first experience going to the gym and my trainer, I was in my thirties already. I'd never lifted anything. It was like, okay, well, one of the critical things you now need to do is eat two grams per kilogram in order to get any benefits. 

Why is there this debate, and where does this come from, and why are you so confident? And maybe also why, on the other hand, you feel that not 0.8 number was too low.

Maybe just give us a bit more of this, because I think that will help us all to feel confident in the answer. 

Professor Stuart Phillips: It is charged. I think that there's a lot of people who, myself included, have invested a lot of time into doing investigations and looking for the answer to this. 

Starting out with the recommended dietary allowance, recommended nutrient intake, so it's established with a method called Nitrogen Balance, and it's essentially exactly as it sounds, the balance of nitrogen, which is that we've already decided is the essential thing that makes protein or amino acids. 

And it's how much you take in all your food and all your drink, and how much you excrete. And so I do think, and I could be wrong here, that I may be one of the few people who's still active in doing protein, who has actually done a wonderful nitrogen balance experiment.

We collected everything. We collected urine, we collected feces, we did sweat wash-downs on people after they had exercised. It's so much fun. They're delightful studies to conduct. 

The balance of nitrogen should be, if your protein in and out, should be zero. 

The problem with nitrogen balance is that from a physiological standpoint, there is nothing that I can say about your physiology when you're in nitrogen balance.

There is this issue of, if we give people more and more protein, that the balance of nitrogen gets increasingly positive, which should mean that you're retaining more and more nitrogen. 

But we've already said we don't do that, so we can't really explain why that happens. We've got some ideas.

But those two, I'll just call them observations to me, really indicate that the methodology is not particularly good.

So, fast forward to 2025. We've got some methodologies now that I think are better. The problem in science is coming to some degree of agreement about how good those methodologies are. I'll be honest about that. So not everybody agrees. 

But we do have some observational studies looking at people's protein intakes. And if they are a little bit higher than the RDA, as people get older, they tend to have better muscle mass, they tend to have better mobility. They tend to be a little bit stronger, and they have maybe have a small survival advantage.

But is it so high that the protein intakes that are twice the RDA are better? I don't think that's the case. 

So, the RDA, I think, is too low. Higher than the RDA is better, but how much higher? That's really difficult to determine. 

I think it's the difference between what do you require i.e. need, and what is optimal? What is better? 

And nutritionally, to give you another example, vitamin C was recognized for a long time for its ability to obviously prevent you from getting scurvy, and you know, who wants to get scurvy, right? No thanks. 

But the recognition was that consuming more vitamin C over and above what you needed to prevent scurvy was good. And that was added to the intake to say, this is good, you get better immune function, smokers need more. 

But that extension hasn't happened for protein. And there's probably lots of reasons for that. Not the least of which would be the disagreement about how we replace nitrogen balance as a method to determine protein requirements. 

Dr Federica Amati: That's super interesting. I think what's also important is that our ability to maintain nitrogen balance changes over our life course. And when we are challenged with lower protein intake, our bodies become more efficient at maintaining the nitrogen balance.

Because protein is so important, our metabolism adapts to make sure we get what we need. 

Actually, there is also evidence to show that if you decrease protein availability in the diet, if you are under the age of 65, you still have this metabolic flexibility to maintain nitrogen balance with lower protein intake. 

Jonathan Wolf: You've used this word nitrogen balance, both of you a couple of times, and I haven't followed the link between that and the amount of protein. 

Can you just unpack that? 

Professor Stuart Phillips: Well, so in simple terms, it's protein in minus protein out. So if protein in is greater than protein out, it means that you're retaining protein.

So we can forget about nitrogen and just call it protein if you want. If protein and protein out are balanced, we're good.  We're eating the right amount and we're excreting the same amount. All good. 

The negative situation, protein out is exceeding protein in. We're losing protein from some pool, chances are we're losing it from muscle. I think, as Federica's already said, cancer weight loss, GLP-1 induced weight loss, for example. 

I think in those sit situations you have to realize is that muscle is lost, but then, you know, maybe some other processes and, leaning on a term called adaptation or being sort of down regulated and we're able to then come back into nitrogen balance because we have this amazing adaptive capacity to withstand, if you like, lower protein intakes. 

Probably, again, realizing the essential nature of protein for normal physiological function.

Jonathan Wolf: So if I'm in protein balance, which was your nitrogen balance, does that mean I am getting all the protein that I need? 

Professor Stuart Phillips: That's correct. 

Jonathan Wolf: In situations where maybe I am getting less protein, my body might make adjustments. So that actually, it can now cope with this lower level of protein. I'm in balance.

So you are saying both of you actually have not really got a problem. It's like I've sort of become more efficient somehow at using this. 

Dr Federica Amati: For some time. Right. But then, if you prolong that and you don't have enough protein for too long, then you start to run into troubles where you don't get enough protein, but your body tries really hard to maintain balance for as long as it can.

Some of the studies I've seen is about six weeks. Is that about right? 

Professor Stuart Phillips: Yeah. When we're in negative protein balance, we reestablish zero protein balance pretty quickly. 

So what that means, to come back to the Lego building block analogy, is that the processes that are using those building blocks have kind of slowed down. And you probably have a period of time where you're flexible and you can withstand that. It's not a big deal. 

But if your protein intake goes too low for too long, then that's when these adaptive processes become, if you like, an issue, and you begin to tap into proteins that are in your muscle, and maybe immune function gets a little bit lower.

But you know, I think that it's probably fair to say that the RDA is a pretty good, I'll just call it a baseline estimate. I'm not suggesting that it's 2, 3, 4 times the RDA, which I think a lot of people are out there saying this is where you need to aim. 

But it's at least, I think about 20 to 50% higher than what most people recommend.

Jonathan Wolf: I'd love to talk about different groups now. Maybe firstly, are there particular groups that are at more risk of not getting enough protein, and where these numbers of sort of, you were saying 1.2 maybe is too low. 

Dr Federica Amati: Yeah, so as we mentioned earlier, is children. So children have a high protein requirement. So where there is no access to food, children are at real risk of protein malnutrition.

I will say again, this is really only really seen in low-income countries. So children in the U.K. and the U.S. luckily have access to food to get enough protein.

Then later in life, it's after the age of 65, you start to see that there is this increased requirement for protein intake. And it's a combination of, as Stuart said, sarcopenia, so muscle mass loss, reduction in appetite. Also, we become a little bit less efficient at absorbing it, a little bit less efficient at getting it into the tissues it needs to go into. 

So the whole picture then means that actually increasing that recommendation in these groups is important.

And then, within older people, those who have chronic illness. So people who have a higher requirement for their immune function, if they have higher inflammation levels, that also requires additional protein. 

We've touched on cancer patients, which is actually a group where not enough protein can actually be the difference between life and death quite a lot of the time.

Those groups, I think, have I missed anyone? 

Professor Stuart Phillips: No, I think that's a, that's a pretty good summary. 

To come back to Jonathan's 17-year-old son, the belief there would be, of course, because you're gaining so much muscle, is that somehow protein is going to be the limiting step for that.

We've done a lot of work in this area, and I can say with pretty good confidence that the big driver, and by big, capital BIG, is lifting weights. 

Protein never really limits your muscle gains unless you're preparing for a bodybuilding competition. So they're desperately trying to lose weight, but they're trying to hang on to their muscle. And you know, that's a scenario, but it's not the scenario that most people are in. 

So let's just say weightlifting is the big thing as opposed to the protein. 

Jonathan Wolf: I was just describing the scenario when I first went to the gym, and my trainer says, You need to eat two grams per kilogram. And it's not like he just made that up off the internet.

So this is very strongly embedded in a lot of physical trainers, a lot of people you go to see. So I'd love to discuss a bit more what does this cutoff come to? 

So what is the number that you are saying, if I'm going to the gym? And is that  if I'm going to the gym three times a week, what about if I'm going every day?  

What is the number that actually, you should be hitting? 

Professor Stuart Phillips: Yeah. So to be really, really clear about this, going to the gym and lifting weights, if you're trying to gain muscle, or if you're older and trying to prevent the loss of muscle, is categorically the primary stimulus that's going to result in muscle growth, or retention of muscle as you age.

Protein helps, but the analogy I like to use is that lifting weights bakes the cake, and protein is that thin layer of icing, as delicious as it is, across the top of the cake. Or maybe it's even the sprinkles on the icing, I'm not sure. So it's a small dressing on top of that. 

If you’re one of these hardcore folks and you're doing CrossFit and you're hitting the gym three, and four times, maybe you do have an increased requirement for protein. There's a lot of wear and tear that goes on in your body that you probably need to replace some of those damaged proteins. I think it could be as high as about 1.6 grams per kilo. So that's twice the RDA.

I know a lot of people will say, Wow, that sounds like a lot, but recognize that it's much below the two grams per kilogram. Or traditionally the 2.2 grams per kilogram, which the bodybuilders would say is the almost folklore level of one gram per pound. 

When we talk about overcooked concepts, and you asked me about things I changed my mind on and this is one. 

We performed two, what are called meta-analyses, where we looked at a lot of the literature, and I remember one student of mine, he came back and he showed me, and I was like, That's not much at all for the extra muscle. 

And it really was, I don’t know if it was an epiphany moment, but it was this gradual realization that a lot of what I'd been cracking the whip on, I'm like, I don't think that's actually right. It takes time to undo learnings, my own included. 

I've tried to get the message out that it probably overdid it, but now the horses out of the stable now. And so things have sort of gone radically off in terms of recommendations and intakes I think, without any good science that backs it up. 

Jonathan Wolf: Are you saying by far the most important thing is how hard I'm working in the gym for determining my ability to put on these muscles?

Professor Stuart Phillips: Absolutely.

Jonathan Wolf: And as long as I'm not really, really deficient in protein, actually, it doesn't make a very big difference. If I was eating one gram per kilogram, I'm probably still going to get a lot of the muscle gain from the gym. 

Professor Stuart Phillips: You may get all of it at one gram, it might take you a little longer, but the thought experiment is how much difference that number makes. I'm sheepishly saying maybe not as big a deal as we once thought. 

Jonathan Wolf: And you're saying that sheepishly, because if I'd interviewed you 20 years ago, what would you have said? 

Professor Stuart Phillips: The younger, maybe better-looking version of me, less wrinkled, definitely would've said, No, no, Jonathan, you need to get this intake. And it would've been at the higher end. 

I'm less and less convinced that's the case, and more with the aging population, where they're retaining muscle and aging wins, and it's the question of whether you age like this with muscle or you age like this, and you only require a little bit of protein to make that happen.

But once you begin to lift weights, it's the magic, that makes you really hang on to muscle. Or if you're a young person, to gain muscle. 

Jonathan Wolf: So if you're not going to the gym, there's no magic to eating more protein than most people have. You're not going to get any benefit.

If you are going to the gym regularly, I think you were saying 3, 4, 5 times a week. 

Professor Stuart Phillips: Well, the recommendations are two sessions of resistive exercise. Your 150 minutes [of aerobic activity], that's the WHO U.K., it doesn't matter where you are in the world, that's universal. So, you know, you've got to do both. I'm more of a lifter than I am a walker or a runner.

But you definitely have to get both to get all the health benefits. 

Jonathan Wolf: If you want to get the optimal return out of that effort. And I have to say I don't love going to the gym, so I do feel like I'm definitely doing it for the benefits.  

Professor Stuart Phillips: You're a mortal, you're doing your stay.

Jonathan Wolf: Then you're saying getting up to 1.6 grams per kilogram if you're really working out that much, will get my optimal benefits on muscle. 

But actually, what I'm hearing is if I was down at one or 1.2, it might be a very small difference, and so I shouldn't obsess about this versus other things. 

I don't want to put words in your mouth, I'm just want to make sure I've understood.

Professor Stuart Phillips: That's a pretty good summary. 

I mean, the other analogy I've used is, you dip a cloth in water, and every time you turn it, the water that comes out is a benefit. So, this is you going to the gym, lots of benefits. And the last little part here is that's where the protein comes in, and you gotta twist it pretty hard, and you get a few drops out and that's the protein layer on top of all of this. 

Jonathan Wolf: Can I ask one last question on this? Which is your own diet; so you do still go to, you do still go to the gym. I can tell that you work out. For people on audio, Stuart is in much better shape than you might pick up from his self-deprecating comments. How many grams a kilogram do you go for?

Professor Stuart Phillips: I'm probably around 1.3 to 1.4, on most days. I definitely don't focus on protein. I do have a protein-heavier meal, which, like a lot of people, is probably your dinnertime or suppertime meal, your last meal of the day, give it the global definition.

I think about it, but I certainly don't, you know, weigh things or obsess about. I'm definitely a very mediocre athlete slash whatever, and I'm a mere mortal these days. I'm not training for anything other than to age well.

Dr Federica Amati: We haven't talked about one important thing, which is that the majority of adults get around 1.2 to 1.4 grams a day without trying.

Our diets have protein in them. But at the end of the day, most of us who are eating enough food, and I have to stress that. So if you're getting enough food, you're getting about 1.2 to 1.4 grams a day. That's the average for U.S. and U.K. 

Jonathan Wolf: This actually came up, I think, in one of my podcasts, where some said to me, when you do exercise, you find you're hungrier.

And I was like, Oh, I do. And they're like, What happens when you're hungrier? And they're like, Do you eat more food? And I was like, Yes. 

And I assume out of this, just as a consequence of what you're talking about, that I'm going to eat more total amount of protein as part is this? 

Professor Stuart Phillips: This is where Christopher Gardner and I, a good friend, we agree to disagree on a few things, but he makes a great point, and it's a good one to sort of maybe keep in mind. 

He's at Stanford University, so big U.S. University, and in North American football players. So they eat a lot of food.  I mean, these guys, they're big men. They're eating at, you know, 3,000, 4,000 calories. And even if you ate, you know, 10% of your energy intake at that sort of caloric intake as protein.

As big as these guys are, they're hitting, you know, 1.7, 1.8 grams per kilo, without even trying. 

But Christopher's fond of saying there's a lot of protein supplements and everything, so then they are into the 2.3, 2.4 grams per kilo range, none of which I think is useful or doing anything for them, other than reinforcing the belief that that's what they need. 

But, it's almost without trying that it happens for very active people, particularly those that are trying to sort of bulk if you like. 

Dr Federica Amati: Also, I do think to your point, a lot of people think they're in this group. A lot of people think they're pro-athletes or that their requirements are super high, and it's really a very small percentage of the human population that has these specific requirements for very hard to obtain goals.

Earlier you said, Jonathan, if someone's not active, if they increase their protein, will that do any good? 

Not only will it not do any good, because it's not going to grow muscles for them if they don't move, it could actually be doing harm, especially in midlife. 

So what is quite consistent in the literature is that if people between the age of 50 and 65 get more than 20% of the caloric intake from protein, they're actually at higher risk of chronic diseases, especially cancer. 

So if you are essentially not active at all and you're in that midlife zone, increasing your protein intake with supplements or just because you decided that steaks are the best food in the world, you could actually be doing way more harm than good. 

Jonathan Wolf: I would like to move shortly into how do I turn all of this into practice for real around lunch?

Before I do that, there are also lots of questions around the timing and spread of protein, and I think that's also again encouraged by all of these big food manufacturers suggesting that I need to have protein in everything now. 

Thinking back also to my first experience of going to the gym, I realized as well as the two grams per kilogram, the other thing that you said is you absolutely need to eat protein, I mean, I'm slightly making this up, but I feel like within 10 minutes of leaving the gym, because otherwise all of that hard work would be completely waste. 

Professor Stuart Phillips: I’m cringing because that was probably me telling you that at some point.

Jonathan Wolf: Is that right? So it was your research from 20 years ago to some degree… 

Professor Stuart Phillips: Unwittingly, I think we've contributed this narrative, and it's not just me. I'd name other names, but I'll let them remain innocent for now. 

Jonathan Wolf: Well, now I'm having the opportunity to sit opposite you, Stuart. So what is the advice around the timing of eating protein compared, because you've already said you have to do some exercise with something heavy. 

Professor Stuart Phillips: So, you know, priority one is we’ve got to go to the gym. If we don't do that, as Frederica mentioned, absolutely spot on, nothing happens when you eat more protein. 

People talk about a satiety effect. I'm pretty lukewarm on that. That happens unless you really ramp up your protein. So, you know, let's sort of forget about that for now and say, go to the gym then your daily protein intake. 

I like it in that 1.2 range. We can agree most people hit that, some people don't, but most do. After that, the timing is this sort of, you know, and I hate to use the in the margins expression or, you know, majoring in the minors.

It's the last little twist of the cloth that you might get a couple of drips of benefit out. But it's certainly not something that would make me say, you know, immediately post-exercise, you need to get your protein. 

That concept, which was given the name probably, about 15 to 20 years ago, the anabolic window, was tied more to the replenishment actually, of muscle glycogen, which is muscle-stored carbohydrate, than it was to protein metabolism.

But a lot of us did some work in this area to try and see whether this was true. There's a good friend of mine named Sean Aaron, who's down at the University of South Carolina, and he's written a paper called, instead of the Anabolic Window, it's the anabolic garage or garage door. So it's open for a long time, and it's really, really big.

In other words, it's probably open for about a day or a day and a half.

Jonathan Wolf: So I could go to the gym first thing in the morning, eat very little protein until the evening. And if I ate something with lots of protein, then I would still get the benefit from the exercise I did that morning.

Professor Stuart Phillips: Yep. 

Jonathan Wolf: Wow. I could tell my trainer straight after this.

Professor Stuart Phillips: I know, I know. And as soon as I've said that, I'm like, God, am I going to upset some people now? 

Dr Federica Amati: All the post-workout shakes. 

Professor Stuart Phillips: I run into these people, and they're like, I heard you on that ZOE podcast. And I'm like, It's just science. I'm just telling you the science. 

Jonathan Wolf: Can I try the counter then? Because they'll say, Sure, that's  fine, but you're working hard and you want to get the best benefit. And so actually why wouldn't you take the extra few percent? 

So what if he said that, would that change your advice?

Professor Stuart Phillips: And I think that's the rider, you know. 

I had the privilege of working with some very good athletes. For them, it's all about the detailed details. And so putting a medal around your neck and standing on a podium is not who this advice is for, who it might be sort of more pragmatic to begin the so-called recovery right away. And I get that. I understand it.

For most folks out there in regular society doing regular things and just hoping to get to stay a little bit healthier, that type of detail and nuances, I think, it's an inefficient message. 

The big one should be just get enough protein, go to the gym, continue, carry on.

Jonathan Wolf: I'd love to talk about protein sources now. Federica has been very, very patient on this. 

You told our researcher that this was something that you changed your mind on during the course of your career. Could you tell us sort of where you began and where you are today?

Professor Stuart Phillips: Yeah, I mean, I think it's pretty self-evident. There are two, what I'll call the major scoring systems for protein. 

Essentially, they come down to how digestible the protein is, so there's a digestibility issue, and how many of these essential amino acids each protein has. 

When you look at it from that perspective, animal-source proteins would be superior. In other words, they would have a higher score than plant source proteins, and everybody goes, Oh, well, game over, it's got a higher score. 

They're the winner easily. And that was me, 25 plus years ago. 

Fast forward, soy protein was the main plant protein that we had probably 15, 20 years ago. And we noticed that that's just not a whole lot different than, it's usually dairy-based proteins that we're converting and comparing. 

And now we're in a world where you've got access to a lot of plant-based protein sources, and the diversity is extraordinary compared to what it was 25 years ago.

We're beginning to conduct experiments, and we see very little difference between what happens with plant source proteins and animal source proteins. 

I would say that these are purified protein sources when we study this. And so we haven't studied whole diets, or, actually, that's not true, we have. But I can't tell you about that yet have me on in another year. I'll tell you all about it. 

I think it's fair to say that when we do that, even exclusively vegan diets are, if you're judicious about how you plan your protein, you're covered. The closer you get to the RDA, however, and the older you are, then it could be problematic.

I think we’ve sort of agreed is that those are populations for whom we probably need to pay attention anyway.

So plant-based diets are, you know, it requires a little bit of planning, but for younger, middle-age, especially active people, the differences between plant source and animal source proteins is it's trivial.

Another deep in the margins issue in my opinion. 

Dr Federica Amati: Yeah. So we're talking about quality earlier in the quick-fire questions.

So the experiments that Stuart's referring to are like soy protein isolate, whey protein isolate. So these are like the pure protein. 

But when we then look at the protein package, when we think about foods, it's the combination of plant foods that then provide this digestible, indispensable amino acid score.

They actually provide the same score as say, a chicken breast, right? So the key is combining plants that then gives you this really good score. 

And then we take a step further and we think, okay, when we're combining plants, so when we're eating legumes and nuts and seeds, you're not just getting those amino acids, you're getting the fiber, the bioactive compounds, the complex carbohydrates, which you don't get from the protein package in an animal protein.

So, actually, now we're in a place where there's so much evidence, and this is where I get excited, right, that shows that if you switch some of your animal protein to plant protein, you are actually prolonging your life. 

You are increasing longevity. You are decreasing your risk of chronic disease because of this protein package that plants come in.

People say that plants are incomplete proteins that're poor quality. That's not true. The science is very clear. The importance of combining plants is where the magic happens. 

Professor Stuart Phillips: If there's a myth to be busted, and Federica just touched on it, and I hear this a lot too, and Christopher Gardner would tell you all about this, is that people say plants are deficient in these amino acids and they're not.

They might be low in certain amino acids, but they're not deficient. In fact, it's really hard to find a plant source protein that is deficient in amino acids. I find it fascinating to go around the world and, I'll call them food insecure regions, or regions where there's not a lot of animal protein consumed, regions of Southeast Asia, India, South America, the Caribbean.

Everybody figured out that a grain and a legume together were good. 

Dr Federica Amati: Yeah. 

Professor Stuart Phillips: I'm so glad you're impressed, because I tell that to my undergraduate students and they just glaze over and look at me. And I think that's fascinating. 

Jonathan Wolf: Could you help to explain it? Because I also slightly glazed over, as you said. Could you help me to understand. 

Dr Federica Amati: Food synergy you just said? It's the magic of food synergy. 

Professor Stuart Phillips: It is. It's incredible. I mean, it can only be that so many people in disparate geographic areas of the world have figured that out because there's an evolutionary pressure for it to happen. Like ,you survived.

And so I'm trite when I say this, but the undergrads seem to resonate with it, is that grains are low in an essential amino acid called lysine. Legumes are pretty rich in lysine, but they're low in amino acids that contain sulfur. There's two of them, methionine and cysteine, but grains are high in those and when you eat them together, you're good to go. 

You get the lysine that you need. You get the methionine, cystine that you need. 

Jonathan Wolf: And so this is like mixing beans and rice.

Professor Stuart Phillips: Yeah, it's my beans and rice.Lentils and rice. 

Dr Federica Amati: It's barley and lentils, it’s spelt and borlotti beans. Right. 

Jonathan Wolf: So another thing that we've had a lot of listener questions about is the idea of an upper limit of protein absorption per serving.

Is there truth in this? Do we need to spread out our protein intake? 

Professor Stuart Phillips: Oh, we contributed to the noise in this one. We can absorb a lot of protein, I mean a lot, like hundreds of grams, and so there's no sort of upper limit on absorption.

But we did publish a paper at one point that showed that when you ate 20 grams of protein, that was all that your body could efficiently use. 

When we doubled the dose and we went to 40, your body used a little bit more, but it was by no means double the response. And so everybody walked away saying, Oh, well 20 grams is all you can digest and absorb. 

And that's not the message. You can digest and absorb a lot more. Your body just can't utilize it. And when I say utilize it, I mean your muscle couldn't utilize it. 

So we probably confuse some people with that. But people have taken and run with the concept. But you know, we can eat a lot of protein. I think Federica, you mentioned, is that we're very good at absorbing protein.

Rarely does it not get absorbed, and there's a little bit, but as we get older, it does go down. 

Jonathan Wolf: If I ate lots of protein in one meal and not a lot later, actually, that is going to deliver all the protein I need for my muscle growth and everything else over the next day. 

So this 20 grams, this is more to do with some sort of optimal thing, but actually, I'm going to be able to use it all.

Professor Stuart Phillips: Yeah. If you ate it in one big meal or you ate it in three meals, I don't think there would be a lot of difference. 

I think the advantage would go to the three meals. We do have a study going on that, and so again, a year or so from now, we'd probably be able to give you the answer. But the truth is, you can digest a lot of protein.

It's not capped out at 20 or 30 grams. 

Jonathan Wolf: Now, Federica, we have a lot of our older ZOE members who ask for advice on how to eat adequate protein without having to eat more food than they find actually they have appetite for. 

Do you have any simple tips for them? 

Dr Federica Amati: Yeah. Increase nutrient-dense foods. So make sure that you're eating foods that provide essential protein and essential nutrients. 

So when I think about this, I think about things like beans and tofu and nuts and seeds and Greek yogurt. 

They're very nutrientedense, so they don't take up too much volume when you have reduced appetite, that can be really helpful. 

Jonathan Wolf: I would love now to actually turn all of this advice into really clear, actionable advice about what I can put on my plate.

Maybe start with the healthiest sources of proteins. What should our listeners be eating?

Professor Stuart Phillips: Look, I mean, the traditional protein sources, everybody I think could rhyme it off. They probably first say eggs, meat, poultry, fish. Great sources of protein, lots of other nutrients in there. Awesome. 

I think eggs have been on the dirty list for too long. I think they're still a pretty good source of protein. Affordable, lots of good nutrients in there. 

But I think we can now begin to talk about plant source proteins. So legumes, beans, pulses, these sorts of things. As a bioequivalent form of protein, you might have to eat a little bit more, but probably not so much more that you would worry about it.

I think a meal where people, I don't say under consume protein, but that tends to be carbohydrate-heavy is breakfast. And the trend these days, I'm sure it's the same in the U.K., U.S., and Canada, doesn't matter, Australia, is that there are lots of ultra-processed foods that are available at breakfast that really are doing everybody a disservice.

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I like to teach students that if we shopped on the outside of the grocery store, up the produce aisle, meat and dairy grains and stayed away from the middle where all the good tasting, highly addictive, high protein cookies. 

Dr Federica Amati: Cookies, yes, exactly. 

Professor Stuart Phillips: The protein, ice cream, protein, water, et cetera. We would probably be a lot better off. So we eat real food, whole food from that standpoint. 

Then I do like to talk a little bit more about protein at breakfast. My super food at breakfast is Greek-style yogurt. So a little bit higher in protein than the regular yogurt, probiotics. And it's a good breakfast food. Throw some nuts, throw some seeds, throw some fruit in there. It's probably my go-to breakfast just about every day. 

Dr Federica Amati: Yeah. And if you have Greek-style yogurt and you add 200 mL of kefir, kefir is exceptionally high in protein actually. Then, as Stuart said, you have two teaspoons of chia, a protein and fiber powerhouse plus omega-3 ALAs, some nuts and some fresh berries, you have got yourself between 20 and 30 grams of protein in that breakfast in a regular-sized bowl. And it's such a great start to the day.

Back to your point about eggs. Eggs are great for breakfast too, right? And if you combine those with a bread that has whole grains in it, or even a pumpernickel-style bread, you can add some beans to that, you've got a great breakfast that packs protein, other bioactive nutrients, and fiber at the same time. 

So I think pivoting to thinking about how can we include not only protein, but also fiber, also probiotics or say, fermented foods, all these things. Then go back to this protein package. How can we make the most of these meals.

I think what's important to note, is if we think about protein in a hierarchy of health impact, okay. So at the bottom you have these plant-based proteins. That should be the majority of where we get our proteins from. Whole grains, legumes, soy products, nuts and seeds. 

Jonathan Wolf: We’ve said this word, legumes and pulses, often.

Dr Federica Amati: Beans and lentils, chickpeas, peas, green peas, navy beans, edamame beans. But if you think about it as that's the majority of a protein, then the next level up is kefir yogurt. So fermented dairy is a great source of protein, and it's good for us for lots of other reasons. 

Then the next level up for me is oily fish. Oily fish are the healthiest animal protein, so they have the omega-3 ALAs, they are consistently shown to improve longevity, cognitive function. They improve a lot of things. 

Then above that, you have eggs. So eggs are good for us, they're just not quite as good as fish, in my opinion, for a protein source.

And then above that you have white meat. Right at the very top, occasionally, you have red meat. Off the pyramid to the side and should not be a source of protein every day is processed meat. I'm quite alarmed by the rise of beef jerky and other processed like salamis as a healthy protein source.

Processed red meat in no world, is a healthy protein source. Processed red meat is a class one carcinogen and it's consistently shown to be detrimental for health. So it should not be a daily protein source. 

I think about it in that order of how well is this going to serve me for longevity and for decreasing my risk of the long-term chronic diseases that really we're all trying to avoid.

I've made that pyramid up, but I love it. 

Professor Stuart Phillips: I have no issues with that pyramid. I'll say about jerky is that if you're worried about your sodium intake, stay away from jerky. 

Jonathan Wolf: I think what's interesting is that while the amount of protein that you're suggesting is higher than has been the standard guidance. It's interesting that it still seems to line up very much with what we end up covering a lot on this podcast around the ability to eat that with a diet that's really supporting your gut health and things like that. 

So I feel that's actually very positive. I would like to directly talk about protein supplements. Because I think that many people jump to protein supplements. 

Again, when I first went to the gym, the consequence of all of that advice was, well, you need to eat all of this protein really fast and you've got this really high number. So, you know, start taking this protein supplement straight afterwards, which I did for a number of years.

Now I really worry about it because I look at it and I see that ZOE says, this is a high-risk processed food. I gave that up as I started to understand in the last few years, all these issues around processed foods. But obviously it gives you a lot of protein. 

What are your thoughts on that, Stuart?

Professor Stuart Phillips: So, pros and cons. The pros of a protein supplement, it's just protein. If it's protein powder and you don't have, you know, a lot of people, they're like, Well, I don't want fat, I don't want carbs because you know, they're going to kill you and et cetera. So yeah, I'm being trite, but you get my point.

I get it. And maybe there's a time and a place for that. It's convenient. And when I deal with a lot of athletes who are in different places, they don't have access to the foods that they would normally eat. 

Outside of that. It's really hard to think of too many pros. The cons are, as you point out, it's processed, it's stripped of other nutrients. I mean, I love your pyramid.

The other part is, we put the big umbrella over the top, and it's pretty delicious too, right? I think that we've lost a little bit of sight of food as an enjoyable commodity that we spend our time cooking and eating, and with friends sometimes.

And we focus on nutrition and its ingredients, but we all eat food. And I think, maybe we've lost sight of some of the enjoyment that comes with eating food. 

So from that standpoint, when you look at some of the bars that are out there and you look at their contents and you look at the amount of sugar that is in them, the amount of sodium that's in them.

I'm okay with those if you think that that's a snack. But you know, just let's be clear that it's not a free pass, and a lot of people say, Oh, it's healthier than a chocolate bar. And I'm like, Well here's the chocolate bar. This is how much healthier the protein bar is. 

It might be a small nudge, but it's not like this is a free pass and this is super healthy and hopefully we've made the point clear that that window and everything else is sort of overhyped in terms of its importance.

I know it's boring, but a food-first approach is going to serve you a whole lot better than any form of supplement will. I work with athletes and I will say is that they go to supplements, and the number one reason for it is convenience. 

Dr Federica Amati: If you are having a whey protein isolate or a soy protein isolate added to your smoothie that you're making yourself, there's less risk.

But a lot of these supplements are high-risk foods. So if you have a Snickers bar, it's a high-risk candy bar. If you add protein to it, it's a Snickers bar with protein, but it's still a Snickers bar, right?  It's not actually a good source of protein. 

The data is also really clear that the more of these foods, these high-risk processed foods you have, the more you are decreasing your chances of living a long and healthy life. 

So the study, I love, the Tessier study in Nature, they calculated that ultra-processed food and high-risk food consumption gives you 32% lower odds of healthy aging. 

So when we think about protein supplementation, are you just adding whey protein isolate because you're an athlete? Or are you eating protein cookies? If it's the protein cookies or protein Snickers bar, you're actually possibly actively reducing your healthy life years. It's not a good idea. 

So protein supplements, I think, is too broad a term nowadays. It's gone from being genuinely just added isolated protein, to junk food that has got a protein health halo sprinkled on top.

And that to me is just a no. 

Jonathan Wolf: I mean, the thing that I'm struck at the end of this is, once again, there's been a big role of big food companies into this story, right? 

Because you've talked about these individual foods as being really bad, and both of you are very aligned on that. But it's not just randomly happened that you get the Snickers bar that says high in protein or the ice cream ready of these.

And I think they play incredibly strongly to why there are so many listeners who contact us and ask, because people see this all over the supermarket, and they're like, Oh wow, I must be short of protein. And also, Oh, so if I get the thing that's high in protein, that actually means that this food, whatever it is, is going to be good for me.

And it's incredibly cynical. 

Dr Federica Amati: And there's usually a markup. People will pay 20% more for the same product with added protein. Great money maker because whey protein isolate is super cheap. So you add that to your waffles, frozen waffles, and you're suddenly selling them for more money and making more money in the process.

It's a complete marketing play, unfortunately. And it's not serving people's health, it's just serving profit margins at the moment. 

Jonathan Wolf: Final question, Stuart, we've gone through lots and lots of advice. 

If I was going to ask you to speak to the listeners and just give one simple actionable tip that they could take away right now that would start to make a change to make them healthier, what would it be?

Professor Stuart Phillips: Does it have to be nutrition-related? 

Jonathan Wolf: No, it doesn't. 

Professor Stuart Phillips: Then exercise. It seems trite, but after years of doing this, and essentially believing, thinking, based on data, that protein was more important than it was. I've come to the realization that it's the exercise that really drives the bus. And protein is a small part of the benefit that could accrue from doing the exercise.

That doesn't matter whether you're a runner or a lifter or anything, that's far more important than getting more protein in your diet and enjoy food. 

I just think that we've obsessed around ingredients for too long and we've lost the sight of a little bit of what it means to sit down and make and then eat a good meal, whether it's by ourselves.

I know it's not always motivating, having lived alone, to cook for yourself, but particularly with other people. The older I get, I think meals with friends, those are special times and should be cherished for sure. 

Dr Federica Amati: I would love people to start thinking about how they can replace some of the protein they're getting from animal foods, like processed meats, red meats, or to your point, Jonathan's snack foods like protein supplement cookies to healthier plant-based proteins that we know are going to improve longevity and outcomes in the long term.

So how can you integrate more lentils, more beans? Can you try tofu or tempeh? Try different oily fish, like add mackerel to your shopping list, add some anchovies, some tin sardines, and just really see how you can integrate these healthy proteins into your everyday life and get rid of some of the ones that are likely to be doing more harm than good.

Jonathan Wolf: I'm going to try and do a summary at least of the key things that we covered. 

I think my starting point is the recommended daily protein intake, which is sort of 0.8 grams per kilogram is too low. And so that is really interesting. 

The second big thing I'm taking away, you have to lift something heavy to get any benefit from protein. So if you're listening to this and you're not lifting anything heavy, don't get tricked into all of these products saying eat more protein, because it's not relevant.  

The question is, what could you do to lift something heavy in order to use it? 

The next thing in my mind, and Federica, I know you've been doing a lot of work on this, is the right amount of protein for you is personalized. There isn't just one single number. And that's, I think, part of the reason you're talking about this recommended daily intake being too low. 

So you're saying, for regular healthy adult, it might be  1-1.2, so it's a bit higher than the number that we've described. But in certain cases, and you're particularly talking about people as they're getting much older because it's harder to absorb this, and it's so important to protect them, it might be higher.

When you're very young, you were describing what you get in breast milk, and it's a bit higher. But in no cases is it as high as we've been hearing a lot from sort of influencers and indeed from the trainers if we go and see them. 

So, I think your own intake is really interesting. You say sort of 1.3 to 1.4, and you're obviously serious about wanting to protect your health and going to the gym.

If you're working out a lot and you're talking about this is the CrossFit, power athlete, hardcore… 

Dr Federica Amati: 0.1%

Jonathan Wolf: Optimizing this at the very best is at 1.6. So again, still well below the 2. So even if you're aspiring to that, that sort of 1.6.

The big thing that you've changed your mind about is this idea that the only way you can solve for your protein intake is eating lots and lots of meat. And that actually, that's really a myth.

It turns out that plants are not deficient in amino acids, but you can't just eat one plant. So you've gotta eat this sort of balanced diet.

That timing is not a big concern. So again, unless you are literally competing for your country, you don't need to worry about eating protein immediately after your workout, which again, reduces some of this pressure, I think, to eat these protein shakes.

Because if you're out and about, then you sort of have to do it immediately. But if you've got more time, then I think comes into play. 

And then I think you talked about some really practical things, which I thought was really great. You could think about breakfast where you're probably not eating a very healthy diet and you may not be getting very much protein. 

Greek-style yogurt mixed with kefir, which I had not realized was particularly high in protein as well. But also eggs and whole grain bread, that's a fantastic breakfast. So breakfast being one of those things you could really change to  improve both health and protein. 

And then in general, there are these obvious things we think about being protein, eggs, and maybe oily fish and dairy. Those are good. But actually, there are all of these things like legumes and pulses, as your chickpeas and lentils, and beans that actually have lots of protein in. 

I was worried you were going to tell me I wasn't getting enough protein, but actually, I think it sounds like I'm going to be okay. 

Professor Stuart Phillips: The odd part again about the complementation that we talked about, about the grain and the legume or the bean is these days, because in past times when people had to do that, the legumes were the rate-limiting thing. They were hard to find. 

Now we can get them almost everywhere. And there's a variety of different sources. It used to be there were two different types of beans, and there were peas. Now it's, it's all kinds of things. So I think that that's an important point.

The pairing with the grain, it might be tasty. It's actually not necessary if you eat enough legumes, 

Dr Federica Amati: But it makes a great base for any meal. If you have a legume and a grain. Quinoa, peas, beans and barley, spelt and lentils. It's just instant. 

Professor Stuart Phillips: If we could take the protein out of quinoa, it has the same protein quality score as milk.

Dr Federica Amati: Huh… There you go. 

Jonathan Wolf: Amazing. If you found this episode with Stuart and Federica useful, I know you'll also enjoy watching this conversation with Federica on protein supplements, where we talk about the health impact of protein bars and powders, and ask whether extra protein can help you to lose weight.