Protein, amino acids and plant vs animal: Dr Paul Morgan, the full interview

Do you want to start with an introduction of yourself and your research?

Paul Morgan, based at Manchester Metropolitan University. I've been here for about five years now; before that I was at the University of Birmingham, and before that the University of Exeter. My PhD was supervised by a guy that many of your listeners will know, Professor Andy Jones, the guy that started most of the beetroot research. My research background has transitioned from fatigue nutrition to more of a human performance focus, and when I say performance that's a really broad term: performance in the context of health and disease as well as sports performance. Looking primarily at muscle adaptation, but more broadly lean tissue adaptation, because some of my funding now is going towards that gut-muscle, inter-organ interaction area. My main area of research in my lab group at the moment is skeletal muscle protein metabolism.

What does that actually mean, skeletal muscle protein metabolism?

Good question. I was at a public engagement event last week with patients with a muscle disease and I said something like "muscle regulation", and to me that seems very straightforward, but to the layperson it probably sounds a lot more complex than it needs to be. Long story short, it's essentially how muscle builds itself: becomes bigger, becomes stronger, becomes leaner, whatever, and breaks itself down. Because muscle, as hopefully many of your listeners will know, is a metabolically active tissue. What I mean by that is even as me and you are sat here talking right now, doing nothing other than talking, we've got muscle tissue being broken down and being regenerated or rebuilt. And that's a really positive and important thing to happen, because what happens through days, weeks, months is the proteins, or the amino acids in the muscle tissue, become faulty. There are processes in the body that identify these faulty parts, like a faulty brick in a wall: you remove that brick from the wall and replace it with a new, non-faulty brick. That's essentially what happens with muscle.

I think that's important to stress, because as soon as we say "building up" and "breaking down", people naturally have a negative connotation to breaking down. In some contexts it is negative, but in a normal, healthy individual, breaking tissue down and rebuilding it is a really positive process. That's ultimately what we're interested in: how the muscle builds itself up, breaks itself down and rebuilds itself according to different interventions. They might be dietary interventions, exercise interventions, protein-focused interventions, or specific scenarios: some of the funding my lab group has received is looking at certain muscle diseases, and how the disease impacts the building and rebuilding of the muscle tissue.

A question that just came to me. You said we're sat down now and there's tissue being broken down and repaired. I believe I've heard that muscle is only built when you sleep. Is that true?

No. No, no, no. I don't know where that's come from. I must say I've heard of most things, but I haven't heard of that one before. What is interesting is that during sleep, I wouldn't say it's a black box, but it's probably the part of the day we know least about in the context of muscle building and breaking down. What we do know is that the muscle responds to protein being provided, and obviously what happens during sleep is protein isn't being provided.

Muscle turns over really slowly, by the way: about one to two percent per day. It's a really slow-turning-over tissue, about the same as bone. And if listeners are going, what's he talking about, turnover? That's the process I mentioned earlier: building up, breaking down.

What's unique about protein is that out of the macronutrients, carbohydrates, fats and proteins (and I'll get shot by the experts on hydration if I don't say water, which is also a macronutrient; Lewis James at Loughborough always says it's the forgotten macronutrient), it's the only one that doesn't have an inactive reservoir. What I mean by that is it doesn't have a storage depot somewhere in the body that's just doing nothing until it's used. Carbohydrates have two storage depots, one at the liver and one in the muscle, stored as glycogen, just sitting there waiting to be used. Fat is an easy one: you can look down at your forearm and pinch your fat. It's sitting there waiting to be used. Protein doesn't have that. What we have are storage depots of protein for the whole of the body, and one of them is muscle.

What essentially happens during periods of starvation, where you need those amino acids, is you have to get them from somewhere to regenerate the other tissue that keeps us alive. Remember that skeletal muscle, you look down at your leg, that's not keeping you alive. What's keeping you alive is your heart, your lungs, your kidneys and so on. They also need to be turned over; they've got amino acids and proteins that are being broken down and rebuilt, and they have much more critical needs than muscle. So in those critical periods, or even in an extended period of starvation where you're not getting any more protein in the diet, they have to get those amino acids from somewhere, and that predominantly comes from skeletal muscle. That has a really important role to play in some of our protein recommendations.

If I take a step back: I don't know how naive your listeners are, and I don't mean that negatively, to what a protein actually is. This is going to sound like a mega cliche, but amino acids really are what many call the building blocks of life, because they build almost every tissue in the body. An amino acid is essentially a small building block that makes up protein. I always say to people, when I deliver lectures or public talks: don't forget that we don't have protein requirements. When we say there's an RDA for protein, there is, but the reason there is is because it's easy to understand. What that protein requirement actually relates to is amino acid requirements. How much protein do you need in a day? Well, you don't need any; you need amino acids. Of course those aren't mutually exclusive. Dietary proteins, and proteins in the body, are made up of these twenty different bricks, these amino acids. Nine of them are essential, eleven are non-essential, and a couple are conditionally essential. I want to stress that, because whenever you hear the word "essential" it sounds like the others aren't needed. All of the amino acids are needed in the body, in different amounts according to the different tissues. It's just that nine of them we can't synthesise in the body without consuming more protein. I like to describe protein very simply as just a vehicle for amino acids. A tasty vehicle for amino acids.

When you consume a whole protein, maybe plant, maybe animal, generally they taste really nice. When you put all these amino acids together, and these individual amino acids all have different functions, some more mobile, some more rigid, they all have different roles to play in building a complex protein structure, which might be muscle, for example. Different Lego pieces all come together to produce this quite amazing piece of tissue.

On conditionally essential, just so your listeners don't think I skipped it: there are certain conditions where certain amino acids become essential for a short period of time. Pregnancy is a great example; there are a couple of amino acids that seem to become a little more essential, perhaps because we can't synthesise them in sufficient amounts, maybe something to do with providing the baby. I'm now going outside my area of expertise, but there are certain situations where you get conditionally essential amino acids.

You touched on BCAAs. Where do they fit within the amino acids?

The branched-chain amino acids: first and foremost, they are essential amino acids, all three of them. Leucine is the one most of your listeners will have heard of; even people who are naive to supplements have probably heard of leucine. That's the amino acid that's received the most attention, because it seems to have a really important role in switching on the muscle protein building response. As soon as a certain amount of leucine is detected in circulation, or in the muscle, it seems to switch on the building process, or at least significantly increase the rate of new building. All the branched-chain amino acids, isoleucine, valine, leucine, are essential, and they're preferentially metabolised in the muscle, so that's why they've received added attention.

That was going to be a question. If I'm eating shit tons of protein and I'm taking whey, is there any point? Am I not already getting them from those protein sources?

It's a really good point, and I think that's probably a fair point. You're probably getting sufficient amounts of all of those amino acids. It's funny how branched-chain amino acids have taken off, because if you look at some of the original, seminal work from people like Kevin Tipton, who your listeners can search, they showed the branched-chain amino acids did have a positive impact, and they certainly were much better than the non-essential amino acids. But they were no better than just using a mixture of essential amino acids. That's because, as I said earlier, you need all of these amino acids to build muscle tissue. If you're getting just the branched-chain amino acids, you're still missing the remaining six essential amino acids.

I'm sure many of your listeners have consumed isolated amino acids before, probably branched-chain amino acids, which are really popular in the supplement industry. They taste horrendous, right? They taste bitter as hell, or sometimes really, really sweet. I think it's one of very few supplements that have survived any kind of issues with sensory analysis: they taste horrible, but people just suffer them.

For the gains.

Yeah. It's probably one of the few.

How much protein should people be consuming?

It's so difficult to answer, because it is and it isn't. Let me give you a bit of context. The RDA, the recommended daily allowance, for protein in the UK sits at about 0.8 grams per kilo per day. I weigh about 79 kilos, so if I extrapolate that out it works out at about sixty grams of protein per day. Most people interested in supplements will be listening to this and going, hang on a minute, sixty grams of protein, that's not much. It's not a lot at all.

Now there's a bit of context around the RDA that's really important. First, we protein researchers think it's underestimated. I'll let your listeners read some of our publications, and the publications from Stu Phillips and Dave Church, who've done excellent work in this area. We think that for the general population it should probably be over one gram per kilo per day. A small increase, but still an increase. Importantly, the RDA is not based on what I would call biological outcomes. It's not based on whether you're getting optimal muscle outcomes. It's based on surviving. It's basically based on meeting the basic, basic needs of protein. We think it's underestimated, and we know it's based upon survival rather than thriving.

A little more context. The new US dietary guidelines, about six months old now, exploded when they came out, because they're probably the biggest change in dietary guidelines since dietary guidelines have existed. One of those changes was not in the explicit recommendation, but in the messaging around protein: to go from the RDA up to somewhere in the region of 1.5, 1.6 grams per kilo per day. So it's a doubling of the protein, not a change in the RDA, but a change in the messaging.

And remember that protein requirement relates to amino acid requirements being fulfilled. Let's say we keep to that number, sixty grams of protein. Sixty grams of beef protein, or whey protein for your listeners, because it's a supplement of high quality, versus sixty grams of a lower-quality plant-based protein: we're now talking very different amino acid compositions. Sixty grams may have been sufficient for one person when we're talking about high-quality proteins, because the original research was all conducted on high-quality proteins. If you take a lower-quality protein or a mixture of lower-quality proteins, that might not match up. So it's really difficult to say. But based on the research we've done, including meta-analyses in this area, we think that at around 1.6 grams per kilo, which is what the US guidelines mentioned as well, whether you're following a plant-based diet or an animal-based diet, you're probably covering all of your amino acid requirements and more. That's where the current line of thinking is. If you're looking at building muscle tissue on a mixed diet, I think somewhere in the region of 1.2 to 1.6 grams per kilo per day is sufficient.

Protein recommendations as they currently sit are based on a normal distribution. The original science that informs our current recommendations basically estimated the average requirement for protein in a group that related to the population. What that meant is that for fifty percent of the population, it was sufficient. It sat directly in the middle. If you think about a bell curve, a curve that goes up and back down again, the fifty percent sits right at the top, in the middle. Now on a standard normal distribution, if you go two standard deviations above that, and I know I'm going a little bit statistical here, it covers 97.5% of the population. So that's a really important number to remember. The RDA is derived from the mean population need, plus two standard deviations above that mean, and then you know that RDA covers 97.5% of the population.

What that means is a few things. It means that for some people, the RDA is not only sufficient, it's optimal. For some people. It also means there are loads of different protein requirements in a population; the RDA is general, not specific. And it means you've got a small percentage of the population where the RDA isn't even sufficient. So there's a lot of context required around the RDA. I could talk about this for the whole hour; in fact I did a podcast where we talked about the RDA for nearly an hour.

We have a limited capacity to use protein at each meal. What I mean by that is we can absorb loads of protein. Luc van Loon's lab has shown this: you can consume huge amounts of protein, the body will digest it, absorb it, it will go into circulation, but the muscle has a limited capacity to use it at a single opportunity. The complexity becomes comparing whole foods versus liquid forms of protein, and I won't go down that rabbit hole today.

What happens in that immediate period after is that the muscle remains in a sort of unresponsive state. At least, that's the current consensus; it might change as more research is done in the whole-food area. We think the main reason is that you can't keep building, building, building more muscle, because muscle building is ridiculously energetically expensive. It costs loads and loads of energy. There are probably mechanisms at play that put a dampener on it: you need to stop building muscle now for a period of time, and then you can start again. But throughout, it's really important to remember that most of our understanding is based on acute responses, and on supplemental forms of protein rather than whole food, which is what our diet typically consists of.

Different protein sources have different amino acid profiles: soy, pea, whey, steak, eggs, chicken. Someone might say, I need to hit my sixty, eighty, a hundred grams of protein a day. If they're getting it all from one source, and it's a lower-quality source than steak or whey, what impact will that have on muscle building?

Such a good question. First of all, muscle requires all twenty amino acids. That's the first important thing to point out, as opposed to something like collagen. Then you said: what if they're only consuming one source? It's an important caveat, because when does anyone ever consume one single source? If someone's following a plant-based diet, they're probably consuming loads of different plants, and if they're consuming enough protein they're probably getting enough of these different amino acids, as long as their diet isn't very, very narrow. If they were only consuming pea, that's a problem. But who's doing that?

More broadly: animal sources, if you look at the amino acid composition of the twenty amino acids, more closely reflect what the muscle looks like. That makes sense if you think about a piece of animal tissue. I always say surely the best protein you can consume is human tissue. It's a weird thing to say, I'm not a cannibal, but you've got the perfect amino acid composition. Soy is probably the best example of an isolated plant protein that has a really good amino acid profile. Broadly speaking it has a lower amount of most of the amino acids compared to something like whey, and slightly less leucine, but it has a pretty decent profile. If you look at all the seminal work in plant proteins, a lot of those studies used soy, and it's no surprise there weren't huge differences, because soy is a pretty decent protein. It's no surprise soy is such a common substitute in plant-based foods.

Pea is a tricky one, because it's got lower leucine content, which is a worry, and low methionine content as well. But there are lots of ways you can counteract that, at a single meal or in your habitual diet. One of them is obvious, because it's a common formulation in supplement product development: combining pea with rice. You get a complementary blend of amino acids, a decent profile from combining two different plant proteins. And it's funny, because Stu Phillips said to me once, and I started looking online and found loads on it: these complementary blends appear in nature. If you look across the globe at diets that don't include animal foods, you see these complementary blends everywhere, whether it's Asia or elsewhere. They haven't gone, years ago, "we need to consume those two foods together because they're complementary". It's just happened. It makes you think, as a scientist, perhaps we're not the smart ones.

Let me direct your readers to a review from Luc van Loon's group; the first author, I think, is Pinckaers. They put together a review on the anabolic response to plant proteins, with some really nice graphics, and one of them was how to compensate for lower-quality proteins. I love it because it summarises it perfectly: the four main ways you can counteract lower-quality protein sources. Having a varied whole-food diet is an obvious one. You can extract protein, which is what supplement companies do: they extract protein from whole foods. You can fortify the protein with a given amino acid, which happens loads in supplement and food companies; if you take pea, you could fortify it with those two amino acids, for example. And you can blend complementary proteins, pea and rice as an example.

The other obvious thing: some plant foods have an excellent amino acid profile, they've just got low protein. A great example, thinking about Stu's work again, is potato. The amino acid profile is really good; the problem is you get almost no protein per potato, so you'd have to consume loads of potato to get a decent amount of amino acids. You can just increase the food intake. That's challenging for potatoes, but there are examples where you can simply increase your intake to get those amino acids. A note of caution with plant proteins is the additional fibre. We talk about this in the context of athletes in particular, because too much fibre might be an issue for digestion, ironically. And plant proteins have lower digestibility, so in certain contexts you might get less bang for your buck.

On the potato example: is total protein not just the adding up of all the amino acids?

Exactly that. The only caveat I'd throw in is digestibility. When you look at the amino acid profile, we do this in research: you can look at some of our studies where we've tested the amino acid profile of the supplement, and then tested amino acid availability in the blood, how the amino acids are actually appearing in the blood. You might go, why would you do that? You can see the amino acids in the supplement, they're just going to appear in circulation. They don't. They appear in circulation differently, according to context. You might have someone with a digestive disorder; ageing is associated with impaired digestion. But different proteins are also digested differently. To take a broad stance: plant proteins have lower digestibility, particularly because of the higher fibre content, and animal proteins have higher digestibility. So for the amount of amino acids you're consuming, more are appearing in circulation for the ones with higher digestibility. You are right, it is literally just all of the amino acids added up that are appearing in circulation, but they might appear in the body differently following consumption.

Part of your research is the gut axis. So depending on the state of the gut, that can influence digestion and actually using the nutrients you eat?

Exactly right. We're just finishing off a study at the moment; it's finished, and we're trying to publish it as we speak. The lead author is one of my students, Anna Lazzarato. She took older adults with obesity. Why? Because we know that with ageing and with obesity you get impaired muscle building, you also get impaired digestion, and as a result impaired availability of the amino acids contained within protein. We gave them a sledgehammer gut-health intervention, really high-dose pre- and probiotics, and we characterised the amino acid concentrations in the blood following a supplemental whey protein. There's some indication that even a two-week intervention, taking that sledgehammer approach to someone with impaired gut health, improves the availability of those amino acids in circulation. So there is evidence that the gut can have quite an important role to play. We see this in ageing anyway: higher retention of amino acids in the gut. You're consuming them, they're just not appearing in circulation as you'd expect.

The gut wall is keeping them within the gut; they're not passing through.

For various reasons. Maybe the gut's not permeable enough, maybe it's too permeable, maybe they're being retained by other tissues before they get to circulation, perhaps more focused on turning over gut tissue than getting out into circulation. There are loads of potential reasons.

Last question. I've always been what we call a hard gainer, super fast metabolism, and ever since I've been lifting I've been trying to shove in as much food as I can. Do you think you need to be in a calorie surplus to build muscle? I've always noticed the most muscle growth when I have been. But who's to say that when I'm not in a surplus I'm still building muscle, just so slowly that I'm looking in the mirror and not seeing any progress? The body doesn't care how you look in the mirror; it just wants you to survive.

It's such a good question, one of my favourite questions you've asked today. I feel you: I think we look similar in terms of build, and I've tried for years. Sometimes I feel a bit of a fraud that I'm a protein metabolism researcher and I can barely put on muscle. First of all, and I'm going to steal this from Stu again: Stu always says the best thing you can do for building muscle is pick your parents wisely. You can't do that, but he says it because it's so important. Some people are just more fortunate, some less; it's just the way it is.

On the energy deficit: it's such a good question because it's still asked, and in the public domain there seems to be a bit of uncertainty around it, though in the scientific world we're pretty confident. If you look at the original research in this area, people like Stefan Pasiakos, and Stu Phillips' PhD students and postdocs, they showed a clear effect. Say I'm not on an energy deficit and you are. You take muscle biopsies from both of us, and you've given us both 20 grams of protein before the energy deficit and after. My muscle responds in exactly the same way. Your muscle, for the same amount of protein, doesn't respond as well as it did before. You're just building less tissue for the same amount of protein, or the same amount of exercise. The main reason, we think, is that muscle building is ridiculously expensive. If you're on an energy deficit, it would be a really stupid adaptation for the body to go, we've got limited energy available, let's use it to build more muscle tissue. There are mechanisms at play that seem to say: if you're on an energy deficit, you ain't building muscle.

Now there are important caveats. Stu has shown that if you put people on a really, really intensive exercise regime, and that's important because exercise is by far the biggest stimulus for muscle adaptation, far beyond protein, though protein is needed for muscle to adapt, and you give people loads and loads of protein, so excess amino acids, it seems you can go on an energy deficit, lose body fat and build muscle tissue. It's just much trickier, much more suffering. A lot of that work came from the military, looking at people who are in energy deficit all the time and what can overcome the symptoms they see. Long story short: two key points. Load up the protein, and exercise very, very hard, and you might be able to achieve it. That issue you don't have on an energy surplus, of course. You could then argue what happens if you're consuming too much energy and putting on body fat, is that impacting the muscle response, but that's another argument. The simple answer is you can do it if you're strategic and if you're fortunate.

Something I haven't mentioned: when you're on an energy deficit you see higher amino acid oxidation. Very simply, you start to use amino acids for energy rather than building new tissue, because there's not much energy available. That's one of the justifications for increasing protein intake: if more of the amino acids are being directed towards energy, give them more amino acids. Does that happen when you're not in a deficit? Yes, but oxidation of amino acids on a normal diet is tiny; we typically refer to it as negligible. As soon as you reduce your intake and need energy, you start to get it from amino acids. There have been some really nice studies of higher-dose protein diets in athletes and recreational people in that context.

The genetic thing is fascinating to me. Online, everyone's got their opinion in the gym space: this is the best for building muscle, no, this is. But what if different ways work better for different people?

It's an excellent point. You can look at genes, but you can also look at the muscle, at the amino acid transporters that allow amino acids to actually get into the muscle. They might respond differently in different people; we know they do. I've got this working hypothesis that if you've got someone who's been on a high-protein diet for a long period of time, and then you stick them on a low-quality or low-protein diet, they'll respond really poorly to it, because some of the cellular mechanisms, those amino acid transporters for example, would be a bit downregulated. They become less efficient because they don't need to be efficient. Whereas if you get people on lower-protein diets, and I don't think you can get away with a very low-protein diet, you probably maximise the efficiency of those transporters. So, horses for courses, I think you're right. What happens if we've exposed ourselves to a certain diet over a period of time? Perhaps physiology has changed. There's not one rule fits all. You can look at this data in the papers we and others have published: you get huge variation between individuals.

Well, Ronnie Coleman, right? Something's going right with him. He's got some advantage.

Exactly, exactly.

Whey has gone up in price a huge amount over the past three or four years. I've got a chart in the video from a financial analysis tool showing the cost of a kilo of whey for a brand to buy, and it has just gone up and up for four years. I think it's demand: they're putting it in Doritos, in coffee. It's a marketing thing now, and the supply hasn't kept up, because it takes a lot of investment to build whey production facilities.

It's a really good point that they're starting to use whey in other products. You go to those milkshake shops where you can put anything in a milkshake, and you can buy a bag of protein powder. It sounds insignificant in isolation, but that's the way the consumer market has gone, across the market. Everywhere you go, you can add protein on, or there's whey protein contained in a product; whey protein in ice cream, for example. So it's not just driven by demand but by a marketing strategy that's seen an opportunity. I'm throwing out hypotheticals, of course. When you have too much reliance on one single food type, that creates its own issues, and does it really surprise you that the price has been driven to where it is? I don't think it's the only reason; the state of farming in the UK is a big contributing factor. But there's something to say about the price being driven by demand, which is funny, because demand normally drives the price down: more volume, lower price. One of the companies I work with, quite a small company, stopped selling whey for about a year, which is crazy, because it would have been one of their best sellers. They physically didn't want to increase the price, and they'd have had to, to make money on it. That's where the big companies take over, because they can deal with big fluctuations in price a lot better than smaller companies.

Every brand is looking at their food product and going, can we put "protein" on the packaging? The consumer knows protein's good, and they don't even need to put that much in. The coffees are probably putting in five or ten grams. And the protein brands have been increasing prices a bit, but also reducing the amount in the bag slightly; some are doing 900 grams instead of a kilo. It's still a 30 gram serving.

That's a really good point about gradual reduction; it's where the food market's gone in the last 20, 30 years. But what's a particularly good point in protein is that the serving size isn't going to change. If you change the serving recommendation in protein, you've got a big problem, because you're going away from the science. Whereas you can change the packet size, no problem.

The other thing about soy is the whole oestrogen thing. I know people are going to go, well, soy raises oestrogen. From what I've seen there are studies for and against.

It's an easy thing to go to, isn't it? I think the discussion around that is probably oversold based upon equivocal findings. If you put someone on very, very high-dose soy for a long period of time, I'm not sure, but it's always important to recognise that diets aren't isolated. Very rarely would you eat a plate of carrots; you're eating it with a bunch of other foods. We're never suggesting someone should consume a very narrow, isolated diet, other than perhaps shakes, which are isolated proteins and which some people have as meal replacements. But in a habitual diet it very rarely happens.

I think soy is not a bad option at all, even for non-vegans. For the gym bros who'll say oestrogen, blah blah blah: I take soy, because whey flares my skin up, like all dairy does.

If you speak to most reasonable researchers in protein metabolism, we've said for years that soy is a good protein. Whenever I talk about the inferiority of plant versus animal, because it does exist, and it exists starkly, the one caveat I always throw in is soy. There are other plants that have great amino acid profiles, but the protein density is so low that it's no good. I do think things have gone a bit far the other way, though. Stu Phillips is a good friend and a very good colleague, and alongside Luc van Loon he's one of the two protein leaders in the world. He's done a lot of work in the plant-based protein area, and in fairness to him he's had to swallow a lot of pride and say: my early research was good, but I've clearly shown now that plant-based proteins can be as efficacious as animal-based proteins. But that messaging has come across as "I got it wrong, they're all the same". That's not quite what we're saying. We're saying they could be the same if you're strategic. If you get the right plants, and a decent chunk of them, of course there's no difference, because it's all about amino acids. It's the first thing I say to my students: proteins are just vehicles for amino acids. Ignore the protein. The protein is irrelevant. What's relevant is the amino acids.

For all the proteins we tested, we tested nitrogen and then we tested the amino acids. All the nitrogen tests were higher than the amino acid tests, but for most of the wheys it was what you'd expect, within ten percent, and the amino acid test had a 14% measurement uncertainty, so those were fine. But both the plant ones were significantly different. The pea protein had a label claim, then the nitrogen test was slightly lower, and then the amino acids were about thirty percent lower than the label claim. This is where I think they're being a bit naughty: they've added other ingredients to the protein that are known to contain nitrogen.

I was waiting for you to say it. This is a known thing. I don't think it's that well known publicly, but it is an issue. It's the same sort of manipulative thing people do with the high-protein foods: most of them contain gluten, which we know is a problem, or some other lowish-quality protein that's really cheap. I remember reading about this only a couple of years ago and thinking, that's crazy. Unfortunately it's a limitation of calculating protein. Time and money dictate these assessments, and it's much cheaper and quicker to measure nitrogen content in a whole food than to measure the individual amino acids.

Protein in a food is calculated based upon nitrogen. Amino acids are often measured via mass spectrometry, a very precise method based on amino acid standards. So your more accurate calculation is always going to be the individual amino acids accumulated, rather than what we would call crude protein. That's the same with all foods: if you pick up a food from your local store and look at the protein, that is just crude protein, so you can't be absolutely confident it's accurate, but it's within a reasonable degree. We do a lot of this in research, looking at protein in a commercially available product and then at the amino acids, and quite often there's a discrepancy. Sometimes it's because tryptophan gets destroyed in the processing of these products, but it would require ridiculous amounts of tryptophan to match the protein, so it's more than likely just a nitrogen labelling error, if you want to call it that.

Wheat was another one, right? Wheat has nitrogen but a very weak amino acid profile. Will that have much muscle-building benefit, if it's not got much in the way of amino acids?

That's a really good point. It comes back to the whole point about combining it with other foods: are you ever consuming wheat in isolation? If you were to eat wheat in isolation, no.

The soy one I tested also had quite a big gap with the nitrogen, over twenty-five percent. I did two amino acid tests and they were about twenty-five and twenty-eight percent under. But interestingly, it was still the cheapest way to hit the amino acids. They're kind of BSing on the label, but still kind of the best option.

When you compare the cost to reach a hundred grams of amino acids from soy versus whey, whey is about double the price. Even factoring in an absorption adjustment, soy is a lot cheaper, even though the soy protein we tested was under its label claim on aminos.

It's interesting. That would obviously be population-specific, the absorption. In young, healthy people, even plant-based proteins would be quite well absorbed, to be honest. So there's a little bit more nuance there. It's tricky to take a metric and apply it universally; you can't just say X protein and apply it globally to the population in terms of its cost. It gets mega nuanced, and you could argue whether that level of nuance is needed.

There's a lot to weigh up. If you want to follow a plant-based diet and you're an athlete, that's fine. But if you want to reach these higher protein intakes, what might become an issue is GI distress, because you're consuming so much fibre to meet those protein numbers. If you're a vegan it starts to become really challenging: higher amino acid oxidation because you're exercising loads, sequestration of some amino acids during digestion, and you haven't got the luxury of eating higher-quality proteins for lower amounts of fibre. Unless you consume a lot of isolated proteins, of course, where you can remove the fibre. That could be an option.

I think that'll be the conclusion of the video: per serving, soy loses on the test results, but when you take cost into account you can have twice as much for the same price.

You could take it further and ask: what is the cost? Financial cost? Caloric cost? Environmental cost? Most people are talking purely financially, but there's a lot more, and it's population-, region- and globally specific. I think you can make some general top-level conclusions, albeit they might change depending on X, Y, Z. And some things are so stark you don't need to worry about it; it doesn't change wherever you go. If we talk about collagen as a protein, for example, wherever you get the collagen, it's never going to have tryptophan in it.