in: Health, Health & Fitness, Podcast

• Last updated: November 6, 2023

Podcast #937: Protein — Everything You Need to Know

Protein, along with fat and carbohydrates, make up one of three basic macronutrients of the human diet. Yet for something so fundamental, a lot of confusion exists around protein. What’s the best kind? How much do you need? When should you eat it?

Here to clear up some of that confusion is Don Layman, professor emeritus of nutrition and one of the world’s foremost researchers on the subject of dietary protein. Today on the show, Don explains why animal-based proteins are superior to plant-based proteins, why he thinks collagen is worthless, how much protein you really need to consume and whether it depends on your activity level and age, what happens when kids don’t get enough protein, the optimal times of day to eat protein, who needs to consume protein right after a workout and who doesn’t, and whether you can get enough protein in your diet if you do intermittent fasting. We end our conversation with why Don thinks increasing protein consumption can be the most effective way to lose weight.

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Read the Transcript

Brett McKay: Brett McKay here and welcome to another edition of The Art of Manliness podcast. Protein along with fat and carbohydrates make up one of the three basic macronutrients of the human diet. Yet, for something so fundamental, a lot of confusion exists around protein. What’s the best kind? How much do you need? When should you eat it? Here to clear up some of that confusion is Don Layman, professor emeritus of nutrition and one of the world’s foremost researchers on the subject of dietary protein. Today on the show, Don explains why animal-based proteins are superior to plant-based proteins, why he thinks collagen is worthless, how much protein you really need to consume and whether it depends on your activity level and age, what happens when kids don’t get enough protein, the optimal times of day to eat protein, who needs to consume protein right after a workout and who doesn’t, and whether you can get enough protein in your diet if you do intermittent fasting. We enter a conversation with why Don thinks increasing protein consumption can be the most effective way to lose weight. After the show’s over, check out our show notes at

All right. Donald Layman, welcome to the show.

Donald Layman: Glad to be with you, Brett.

Brett McKay: So you are a researcher that has done a lot of studies on nutrition, particularly dietary protein. And I want to talk to you about protein today because I think a lot of people have questions about protein. What’s the best kind of protein? How much protein should I really be eating in a day? When should I eat protein? And there’s a lot of ideas floating out there in the popular press, but let’s start off with a brief overview of how our bodies use protein. I just had some chicken breast before we got on the show. I ate that piece of chicken. How is my body going to use the protein from that chicken?

Donald Layman: Yeah, you’re right. I think protein’s a complicated topic and I think maybe we can simplify it a little bit. So your chicken breast. I like to remind people that protein is kind of like a vitamin pill. We really don’t need the pill. What we need are the fourteen vitamins inside of it. We don’t talk about the color of the pill or the digestibility of the pill. We talk about the vitamins and that’s really what protein is. It’s really just a food delivery system for amino acids. So when you eat that chicken breast, the very first thing your body does is break that protein down into individual amino acids and there are 20 of them that are naturally occurring. Nine of them our body can’t make, that we call them essential or indispensable. We have to have them in a daily supply. The other 11 the body can make it. It’s sort of if you have enough of one amino acid you can make another one. So nine are essential, 11 are considered non-essential because we can make them. So once we digest it in our GI tract, in our intestine, the body then absorbs them.

How do we make them into protein or in the body or muscle protein? Well, the first thing to recognize is that as these amino acids are getting absorbed into the body, the body begins to use them. And about 50% of every amino acid that you take in in a diet gets used before it ever gets to the blood. It gets used by the lining of the intestinal tract, by the liver, and so only about 50% ever get to the blood. And of those, then the body will use some for energy and some can get made into protein.

So in muscle, about one out of every seven amino acids going into a new muscle protein comes from the diet and the other six actually are getting reused. So the whole system gets pretty complex at that point, but sort of the point of all that is that a single amino acid in that chicken breast you ate, it’s kinda hard to track it directly into a new protein and muscle. So that’s sort of the complexity and we can go from there as to how do we sort out the need and different quality and protein, but that’s sort of how the body’s using them.

Brett McKay: All right, so protein is the delivery for amino acids.

Donald Layman: Exactly.

Brett McKay: And protein doesn’t just make muscle tissue, but it also makes other tissue in our body. I think fingernails, hair, needs protein. That’s…

Donald Layman: Sure. In the body, all adults and even children, anyone over the age of about 16 has to make 250 to 300 grams of new protein in the body every day. Proteins that are in your liver, we’re replacing them almost hourly. Proteins in the blood might last 15, 16 days. Proteins in the muscle might last 30 or 40 days, but we’re continuously replacing those. In fact, if you sort of look at it on a total body basis, we replace the equivalent of every protein in our body about four times per year. So there’s this big turnover going on all the time and that’s important as we repair our body and sort of in the aging process, repair and replacement’s really important.

Brett McKay: Let’s talk about protein and muscle. People typically, that’s what they associate, I’m going to consume protein to grow muscle tissue and the process where our body turns amino acids that we’ve consumed into muscle tissue, that’s called muscle protein synthesis, correct?

Donald Layman: Right. So protein synthesis is a term of every tissue, whether you’re talking about the heart or the brain or the liver or muscle. So it’s protein synthesis and as you point out, people have kind of focused on muscle, but in every tissue it’s the same.

Brett McKay: Okay. So let’s talk about the type of protein we consume. How does the type of protein we consume influence protein synthesis?

Donald Layman: Yeah. So again, we talk about protein as just a food delivery system for amino acids. So the type of protein really reflects the balance of amino acids. And as I said at the beginning, we absolutely require the nine essential amino acids. And so if you look at different proteins, whether you’re talking about a dairy protein like whey protein or a plant protein like soy protein, you look at the distribution of those nine essential amino acids and every protein’s a little different. What we know though is that proteins that come from animal sources, and in this case I’ll include eggs and fish, all sort of animal sources versus plant sources, proteins that come from animal sources always have a better distribution and a higher distribution of those essential amino acids.

If you wanna think about it, plants have amino acids for the sake of plants. They’re not assuming they’re going to get eaten. So they have it to make roots and stems and flowers and seeds, which are pretty different than brains, and hearts, and skin, and muscle. So the way to think about it is plant proteins have amino acids to making plant products, plant structures.

Brett McKay: And so I think one of the research you found, I’ve read this other places, that part of the problem with plant-based proteins is that they don’t have enough of a particular type of amino acid that helps kickstart protein synthesis, correct?

Donald Layman: Right. So of those nine essential amino acids, there are three that we often say are limiting in plants. And those three are lysine, methionine, and leucine. Of those three, one that I’ve studied a lot is called leucine. And what we discovered was that leucine has a very unusual role in triggering muscle protein synthesis. For reasons we don’t fully understand, the body has evolved to recognize the increase in leucine in the blood as a indicator that the meal was well enough balanced to trigger muscle protein synthesis.

Another way to sort of think about that is in the liver, you have to be making proteins 24 hours a day. If you’re not making them in the middle of the night, you’re going to die. You just have to be making them. Same with the brain or the heart. In muscle, we only do it when we have a meal that is adequate. We call it an anabolic response to a meal. And for whatever reason, the body evolved to recognize leucine as that signal that the meal is adequate. So leucine is a very important amino acid for defining what we call protein quality. Is there enough leucine to trigger muscle protein synthesis?

Brett McKay: And that’s why people who do a vegetarian diet, they have a harder time getting the necessary proteins. The plant-based doesn’t have enough leucine.

Donald Layman: Right. So if you look at, just for example, if you look at whey protein, which is a protein that’s become very popular with people who are trying to build muscle. If you look at the amino acids in whey protein, 12% of those amino acids are leucine. But if you look at a grain like quinoa, which people think of as a really good plant-based protein, leucine is 6%. So you have to have twice as much quinoa protein to trigger protein synthesis. That translates into something over seven cups of quinoa at a meal to trigger muscle protein synthesis. So from a calorie standpoint, from a volume standpoint, it’s hard to eat enough plant-based protein to get to the leucine number.

Brett McKay: Yeah, it sound like you’d have a lot of gas. You’d be bloated.

Donald Layman: Yeah. You get a lot of fiber. Quinoa, in my mind, quinoa is a great carbohydrate source that happens to have good protein in it. So it’s a great fiber. It has good nutrients. It’s a great food. But it’s a pretty poor protein source alone. So you really need to have something else with it, whether you’re gonna mix, say, soy protein with it or tofu or you need higher protein sources to make it work.

Brett McKay: Can you supplement with leucine to kickstart protein synthesis?

Donald Layman: You can at some level. We have done that sometimes in situations like somebody is ill in a hospital and they just can’t eat much. We’ve shown and others have shown that if you take in 15 grams of protein, but then supplement that with leucine, you can get up to that threshold to stimulate muscle protein synthesis. We know that you need to have around 3 grams of leucine in the meal. So you could get, say, one and a half from plant-based proteins and add in another one and a half as a supplement of leucine and you can get to that 3 gram level.

Brett McKay: So in terms of delivering amino acids, animal-based is going to be superior to plant-based proteins. Of the animal-based proteins, are some better than others? We’re talking like meat, or egg, or whey?

Donald Layman: I think you have to decide what your goal is. If your goal is to have a breakfast that stimulates muscle protein synthesis, and that’s really your only goal, then whey makes a perfect shake because it’s very high in leucine. You can stimulate muscle protein synthesis with only about 23, 24 grams of protein. On the other hand, if you’re thinking about a balanced diet, something like beef protein is a great source because not only is it a good source of the essential amino acids like leucine, but it’s also very rich in iron and zinc and selenium and B6 and B12. So you have to think about what your goal is.

Brett McKay: Eggs is another example, where the egg is a very balanced nutrient overall, vitamins, minerals, as well as protein. So you kind of have to think about the balance there. Fish, for example, is a very good protein source, but the vitamins and minerals tend to be lower. So again, what’s the balance? I think that’s why nutrition, we’ve always said, well, have a varied diet. Don’t believe that, well, the only protein I should eat is fish or the only protein I should eat is white meat chicken. Those are good protein sources, but actually low in other nutrients.

Yeah, I think that’s interesting. You got to think about the whole picture, not just protein.

Donald Layman: Yeah. In general right now, we’re beginning to focus more on what we call the food matrix. We’ve had what we might call a reductionist approach for a long time, where we think about a food, well, does it have enough vitamin C or does it have enough vitamin D or does it have enough of amino acids? But now we’re trying to think about it more as a meal complex and a whole diet.

Brett McKay: Well, speaking of this idea that protein is just a delivery capsule for amino acids. We talked about the fact that you can supplement leucine. Can you get the benefits of all the amino acids just by taking an amino acid supplement?

Donald Layman: You can. That’s incredibly expensive to do. To take in enough protein, to get 100 grams of amino acids per day would be an incredibly expensive, but people have certainly shown it in hospital situations. People who can’t eat, we can do an IV into their arm or whatever and supply those amino acids. That certainly can be done. My attitude about that is a little like people self-supplementing with vitamins. Do you really have enough knowledge to do the chemistry that resembles food intake that has evolved over a million years? I don’t think most people have the resources or the knowledge to really do supplementation.

Brett McKay: Okay. What about collagen proteins? I’ve been seeing a lot about that. I got my whole foods and I see a lot of rows of collagen proteins. What’s the quality of collagen proteins?

Donald Layman: Collagen, by any measure, is the single worst protein you could ever see.

Brett McKay: Okay.

Donald Layman: It’s deficient in at least four essential amino acids. It’s one that I always sort of scratch my head at. I look at all these testimonials out there that people think that collagen’s great, but the reality is from a scientific research standpoint, it’s awful. I think it’s a total waste of money. Obviously, I’m really negative about it. On the other hand, there’s a lot of people who believe in it. I sort of remain open-minded, but at the same time, I’ve seen no data to make me believe that it’s anything more than just a nitrogen source. When you look at the true protein requirement, it’s actually two parts. The first part is getting the nine essential amino acids, and the second part is getting additional nitrogen. That nitrogen we refer to as nonspecific. And I think, for example, collagen is nothing more than a nitrogen source. If you have a relatively low-protein diet and you want to supplement it with expensive collagen, I guess that works, but if you’re just trying to get adequate protein, collagen’s a lousy source.

Brett McKay: Okay. So the takeaway there, quality, the type of protein, animal-based is going to be your best bet to get all nine of the essential amino acids in the right dosage to kickstart and have muscle protein synthesis going on. If you’re doing a vegetarian diet, you might have to supplement with a higher source protein like a soy protein, and then, yeah, wasting your money with collagen and amino acids. Nature’s already got the pill for you. It’s animal-based protein, so just go with that.

Donald Layman: Yeah. That’s exactly right. And people will often say, “Well, he’s really negative about vegetarianism.” That’s not really the case. My problem with it is that if you look at the data, all the survey data, what you see is that vegetarians typically have lower protein intakes and they have lower protein quality, so that’s a risk. I think that if you’re making that lifestyle choice, you need to understand it. My personal preference would be a blended. I don’t think it’s all or nothing. I think you can be more plant-based. I think that’s great. But using fish or eggs or cheese or something to make it more balanced, I think, is a better choice. So I have no problem with being plant-based.

Being totally vegan is a real challenge. You’re sort of forced to go to ultra-processed foods. You need to have things like soy protein isolates or pea protein isolates to supplement your diet, or, like you said, maybe essential amino acids, which are very expensive. So it’s just a challenge and my fear is the average adult doesn’t have the knowledge to make that work.

Brett McKay: All right. So let’s talk about how much protein we should be consuming ’cause there’s a lot of different numbers out there in the popular press. What’s the typical amount that’s recommended? I think it’s the National Academy of Medicine has put out a recommended daily amount. What’s the amount that they recommend and what has your research shown to be an optimal amount of protein?

Donald Layman: Okay. So the National Academy of Sciences and the Institute of Medicine sort of sets dietary guidelines. So let’s take a non-protein example. So vitamin C, with every nutrient, the Institute of Medicine recommends a range for the nutrient. So for vitamin C, the low end of the range, which we call the RDA, Recommended Dietary Allowance, is 60 milligrams. But we know that you can go to an upper range with vitamin C of maybe up to 10 grams per day, more than 10 times the minimum RDA.

So we know that the RDA prevents a deficiency, scurvy, but when you get a cold or concerned about COVID or something like that, people will take 500 mg or 1000 mg. So the difference between the minimum and the optimum. So let’s apply that to protein. The Institute of Medicine sets the minimum, the RDA, at 0.8g per kg, which is around 0.3g per pound. But it says there’s a range up to some upper limit, and we know that is up around a gram per pound. So a big range there. What we now know is the optimum range for most adults is somewhere between about 0.5 and 0.7g per pound. 1.2 to 1.8g per kg is the way we talk about it. So again, we need to recognize that for every nutrient there’s a range of intake. The RDA, which people hear about, is the minimum to prevent a deficiency. In fact, it’s defined at a level where 97% of the people don’t show a deficiency, but 3% will actually show a deficiency. And if we look at national survey data, what we know is that in women over 60 years of age, 40% are actually below the RDA. So in general, women in particular are particularly low in their dietary protein intake. Men are a little bit higher, but still not up in the range that we think is optimal.

Brett McKay: Okay. So just to put some concrete numbers to this. Okay, the RDA is the minimum you need to make sure you’re not wasting away. So let’s say you’re a 200-pound man, what did you say? The RDA was about 0.36g?

Donald Layman: So yeah, so the range of intake in the United States, the RDA, depending on body weight, is sort of between about 56 and 66g per day. Average intake in the United States is around 80g. We think that most adults should be above 100g. And again, it’s body weight. So if you take a 250-pound male, that person will have twice the amount of protein as a 125 pound female.

Brett McKay: That’s crazy that most people are only getting 80g of protein a day.

Donald Layman: That’s the average based on the national surveys, again, men a little higher, maybe a little closer to 90g, and women a little lower, closer to 70g, but the average is 80g.

Brett McKay: Okay. Do protein requirements change for men and women? So if you’re a man do you need more protein than women?

Donald Layman: It’s based on lean body mass. It’s based on body weight. So men typically are going to weigh more than women, so they need more protein. A 150-pound woman and 150-pound man would have essentially the same requirements. Slightly different because typically women will have a little more body fat, a little less lean body mass. But in essence the requirements are the same based on body weight.

Brett McKay: Does the requirement change or the optimal amount change if you’re physically active?

Donald Layman: That’s a good question. Interestingly enough, people generally assume that, “Well, if I’m lifting weights and trying to build body mass, I need more protein.” It’s actually endurance exercise. We know that endurance exercise burns about 10g of protein per hour of exercise. Like running, a marathon runner for example. So if you go out doing three-hour runs, by definition you need 30g of more protein than normal.

Brett McKay: Okay. So, whenever you exercise, you’re gonna need more protein. And that’s not just for weightlifting. I think that’s really interesting that if you do a lot of endurance sports, you need to be increasing your protein intake a lot. Speaking of consuming protein because you’re lifting weights to get stronger. I think a lot of people have this idea that, “Well, if I mega dose on protein, it’s gonna help me build more muscle tissue.” But your research has found that probably at a certain point, consuming more protein won’t have any benefit.

Donald Layman: Yeah, our methods aren’t great for determining sort of small differences between protein intakes. What we find is that a lot of bodybuilders will look at an intake of a gram per pound, which translates into about 2.2g per kg. The research shows we really can’t tell any difference between 1.8g per kg and 2.2g. So most bodybuilders are probably over consuming protein, but again, they’re looking for sort of a maximum effort. So I don’t see any problem with that. But the research doesn’t really support any real benefit above about 1.8g per kg. And again, I think that translates into about 0.8g per pound.

Brett McKay: Okay. So yeah, I consume… Right now I’m doing about a gram per pound. So I get about 200g of protein. I’m 190…

Donald Layman: That’s very common for people who are trying to lift weights. And again, you have to think about protein in the context of the whole diet. So if you don’t eat 200g of protein, what are you going to eat? And a lot of people say, “Well, I wanna be sure I don’t eat the carbohydrates ’cause that causes me to retain more water and I don’t like the way I feel,” or whatever. “I have tendency toward diabetes.” So from a pure muscle building standpoint, we think that around 0.8g per pound is totally adequate, but there’s nothing wrong with a gram per pound if that sort of suits your needs.

Brett McKay: What happens with the excess protein that your body doesn’t need?

Donald Layman: Excess is an interesting concept. Let’s think about you in terms of a gram per pound per day. How much muscle mass are you gaining this week? Probably nothing.

Brett McKay: Not much. Yeah.

Donald Layman: So if you’re eating 200g of protein per day, where is it going? Basically, you have to burn every one of those grams, the equivalent of every one. So basically, whether you eat 60g of protein per day or 200g of protein per day, you’re going to burn it all for energy. You use it for protein synthesis, but at some level you have to get rid of every gram or you have to store it in some way, which means you’re gaining weight. So again, people think about burning the excess, but the reality is, I mentioned at the beginning, 50% of the amino acids that come into the body are burned in the GI tract or the liver before they ever get to the blood. So this whole concept of burning the excess is kind of a vague concept because we’re always burning everything we eat.

Brett McKay: We’re gonna take a quick break for a word from our sponsors. And now back to the show. And I also, I think it’s important to note that you highlight research that eating a high protein diet, it’s not gonna damage your kidneys. That’s an idea that’s out there. Too much protein is bad for you. If you do have some sort of kidney disease, high protein diet might be an issue, but if you’re healthy, eating a lot of protein won’t do anything to you. Basically, like as you said, any excess protein will be used in the body for something else. So yeah, I think the big takeaway there overall is that if you’re a physically active male, 0.8 to 1g per pound of body weight is probably what you’re looking at.

Donald Layman: That’s a target where the science shows, has really good data. We think that’s your… The upper range that makes any sense. And frankly, the research shows 0.8g is probably adequate, but there’s nothing wrong with going to a gram per pound.

Brett McKay: So if you’re a 200-pound man, that would be 160g per day, protein.

Donald Layman: Right. Up to 200g like you pointed out.

Brett McKay: Up to 200g. I think that’s a lot of protein, but it’s not… Once you kind of figure things out, you know what’s a high source of protein. And it’s easily to supplement with a whey protein. Whey protein’s fantastic. It’s cheap and you can get a lot of great protein bang for your buck with it.

Donald Layman: Yeah, I think most people find that amount of protein pretty hard to consume. We’ve done a lot of research with women, particularly looking at weight loss. We find it extremely difficult to keep women above 100g per day. I personally eat probably 100 to 120g per day. I weigh about 160 pounds. So, again, I think if you’re motivated toward bodybuilding, that’s great. But again, we think the healthy range is sort of in that, a lower end of about 0.55g per pound up to a gram per pound. So falling within that range is probably okay, depending on your personal goals.

Brett McKay: Something I’ve heard is that as you get older, to your 50s, 60s, 70s, 80s, you have to consume more protein. Is that true?

Donald Layman: What we know is that the efficiency of protein use goes down with age. Where does that start? We think it starts somewhere around 40, maybe 35. We know that when you’re still growing, your body is kind of driven by hormone. So when you’re in your teens or in your 20s, your body is making protein driven by growth hormone, IGF-1 insulin. Once you stop growing, now you’re going into the maintenance phase. We know that everything we’ve been talking about, all of this meal balance kind of thing, that starts to come into play in your mid 30s. So your point about the efficiency going down, we think that starts in the 40s. So people need to be making adjustments in their 40s. And certainly by the time you get out into 60 and 70, now you’re confronted with the issue that your total calorie needs per day begin to go down. But your protein need is at least as high as when you were 16 or 25, but now you need to get it in less total calories.

Donald Layman: So the quality of your diet needs to go up, your nutrient density needs to go up, you need to get more amino acids per calorie you eat. And it probably… Is it higher than when you’re 25? It might be. It might actually be higher. I think it’s one of the reasons why you tend to find more vegetarians who are between 20 and 40 than you do between 60 and 80. You just really hard to pull that off to get the protein you need with the reduced calories.

Brett McKay: So just correct me if I’m wrong here, to make sure I understand. So as you get older, does our body just become less responsive to protein? We just have to consume more of it to kickstart that protein synthesis?

Donald Layman: Exactly. When you’re young, muscle protein synthesis and a mechanism we know of as mTOR is very sensitive to insulin. And so you grow because of hormones. Once you get beyond mid 30s, now it becomes sensitive to the quality of the protein and particularly that amino acid, leucine. So we’re changing how the body regulates muscle protein synthesis, and as we get older it becomes more and more sensitive to the leucine amount.

Brett McKay: Okay. So any recommendations there? Just concrete numbers, say, you’re 70 years old.

Donald Layman: We know that the leucine trigger amount is about 3g, probably you begin to get a response at 2.5g. Some people have used up to 4g. We usually use the number of 3g of leucine as your target to activate that system. So if you look at a mixed diet then, let’s say you’re having a meal that has some animal protein, some plant protein, we usually use the number of around 8% leucine in a mixed meal. So that means your minimum threshold, you may have seen the meal number of 30g, 30-35g per meal. That’s assuming leucine makes up about 8% of the protein. So to get to 2.5 to 3g, you need at least 30g, 35g of total protein. So that’s where that meal number comes from.

Brett McKay: Okay. So to recap, as you get older, your body becomes less sensitive to protein. So you may need to increase protein intake to make up for that. So I think the big takeaway there is just yeah, as you get older, be more aware of your protein and then think about how much protein you’re getting at each meal. And we’re gonna talk more here about protein distribution. But let’s talk about kids. What do we know about the protein requirements for children?

Donald Layman: So they change during aging. So in the first year, the two years, the protein requirement is at 2.2g per kg, so a gram per pound. So as a very young child, it’s now what we’re talking about for older adults. The belief then is as the rate of growth slows down, it solely goes from 2.2g down to 0.8g for a 16-year-old. So there’s that shifting process. I think the research is beginning to question does it really go down like that? We know that your rate of building protein is slowing down, but you’re building and replacing so much protein that actually isn’t growth. So I think we’re beginning to question that.

One of the important things about children versus adults is for adults, we’re now talking about the meal distribution of protein and leucine. So we talk about having 35g of protein per meal to get enough leucine. That doesn’t seem to be true for children. Children will respond at very small meals. If a child has 5g of protein at a snack or 10g for protein for breakfast, they’ll grow perfectly fine. Muscle protein synthesis is perfectly fine. So an average 10, 12-year-old is probably targeting around 50g per day and that can be distributed kind of in any way they want. It’s not meal-specific like it is for adults.

Brett McKay: Okay. So with kids with body weight, what’s the ratio, how many grams per kilogram you’re looking at for a child? Is it the same for an adult?

Donald Layman: So again, it’s the RDA for children over six is at 0.35g per pound. So it’s the RDA, is 0.8g per kg.

Okay. And again, that’s just the minimum. Do we know what happens if kids don’t get adequate protein in childhood? Does it have any long-term effects?

Oh, yeah. The biggest international problem with malnutrition is availability of protein. So growth stunting, there’s a lot of… Early in my career I did a lot of international work with children and malnutrition and growth stunting. And so we know that if children don’t develop the lean body mass they should when they’re young, there’s a real high risk that they’re going to be obese. If they don’t have the lean body mass, they’ll tend to deposit more body fat. So one of my concerns now is that, as mothers are hearing about everybody should have a more plant-based diet and they start translating that to children, there’s a real risk that we’re gonna induce malnutrition in children. They’re just not gonna grow correctly. And that’s a long-term risk.

One of the examples I like using is if you take a common wheat cereal and the serving size might be, let’s say it’s a cup, has 4g of plant protein, say a wheat protein, if you look on the label, let’s say, well, you take that cereal and you mix it with 6g of milk, we now have 10g. And that turns out to be exactly balanced for essential amino acids. But now we’re hearing about plant-based proteins and so they say, “Well, switch to soy milk.” Well, we’re not telling people very well, and I don’t think they get is that soy milk is deficient in the same amino acids that the wheat cereal’s deficient in. And so to get a balanced protein mix, you have to have over 25 ounces of soy fluid milk to balance that meal. 25 ounces, we’re nearing a quart. And if you go to almond milk, which is even worse, now you need over 50 ounces to make that work. So mothers need to recognize that basically if they’re doing that with plant-based milks, they’re creating an amino acid imbalance. And why I said that? Younger children can get along with protein at any meal, they still have to have a balanced ratio of essential amino acids. So my comment earlier is that I’m not sure most adults have the knowledge of how to create totally vegetarian diets. They might be able to do it, but very few can.

Brett McKay: Okay. So kids who don’t get enough protein in childhood, they’re not gonna develop lean muscle mass and as a consequence they might develop more adipose tissue, which could result in type 2 diabetes metabolic syndromes.

Donald Layman: Exactly. So that’s what we saw with the international work. If the children are growth stunted, did not develop the lean body mass during their first 14, 15 years, then they’re prone to developing obesity. And as you said, all of the diseases that go with that, diabetes, heart disease, etcetera, they’re much more prone to those kinds of things.

Brett McKay: Let’s shift to protein timing. That’s something I think a lot of people have read about, that there’s certain times of the day that it’s better to eat protein. Is there anything to that idea? Like should you consume protein after a workout? Is morning or dinner a better time for protein?

Donald Layman: So let’s sort of complete the comment with children. As I wanted to emphasize, timing doesn’t seem to be as important for children. So when we talk about timing, we’re talking about adults. What the research shows is that probably the first meal of the day may very well be the most important. We know that we’re coming out of an overnight fast, we know that all of the mechanisms for muscle protein synthesis are shut down. And until you eat a protein meal that has enough leucine till you get to 35g of protein at a meal, your muscle stays, what we call, catabolic. It’s breaking itself down. So we think that the first meal is critical. We also think that a later meal… What we don’t really know is, how important is the middle meal? Something you might do in middle of the day. Nobody’s really studied that, so we don’t really know.

But we know for 100% certainty that that first meal… And I’m sort of avoiding calling it breakfast because that implies that it needs to be super early or something. But whenever you choose to eat it, whether it’s 7:00 in the morning or 11:00 in the morning, that first meal needs to be high protein. You mentioned after exercise. We did a lot of research and others have done a lot of research with exercise because exercise is sort of a catabolic period. Protein synthesis is depressed and so we’re looking at recovery. How’s the best way to build muscle? The thing to remember about that is almost all of that research is done with untrained individuals doing an acute exhaustive exercise. What we know is that the more trained you are, probably the less important that becomes.

So if you’re just beginning an exercise, you’re out of shape, you’re just beginning, having protein, 15, 20g after your exercise within the next hour or so, probably is a useful way to recover. But if you’re well-trained, doing the same thing week after week, when you have your protein after an exercise probably doesn’t make much difference. It’s really the total amount per day. Most extreme bodybuilders will probably take in protein at least four times a day. So if you want one of those to be after exercise, that’s great. But if your next meal happens three hours after exercise, that’s fine too. So I think the whole after exercise thing has been distorted a little bit. All of the research has been done with untrained people doing exhaustive exercise. So if you’re well-trained, the timing’s probably not nearly as important.

Brett McKay: So you mentioned to kickstart protein synthesis with that first meal, you gotta have 35g of protein. Is there any other research about distribution of protein throughout the day? So beyond that first meal, does it matter how you distribute your protein?

Donald Layman: It doesn’t really seem to. There’s pretty good data that having a larger meal later in the day is important. So like a dinner meal that has maybe 50, 60g of protein. And there’s a little bit of research. Luc van Loon in the Netherlands has shown that for individuals, again, interested in bodybuilding, having a fourth meal before bedtime, sort of shortening that… So typically a lot of people will have their dinner at 7:00 and then a breakfast at 7:00. So they’re going 12 hours without protein coming in. So having another protein intake at 10:00 before bed is something that bodybuilders will often adopt. So typically we always try and tell people that if you’re a normal healthy adult, try and get two meals, at least, your breakfast and dinner, where the protein amount is above 35g. If you’re trying to gain muscle mass, you should have at least three meals and possibly even four. So meal distribution takes on, again, a little different look depending on what your personal goals are.

Brett McKay: I know intermittent fasting’s become really popular. Some people might have a shortened eating window, so it might just be like a few hours. Is it possible to get all your protein requirements in that maybe four hours that you have to eat?

Donald Layman: Yeah. I don’t like patterns as short as four hours. We know that the mechanisms for regulating protein synthesis once you turn them on, they’re all active for at least five hours. So I think that the next meal needs to be separated by at least more than five hours. I like the concept of… The idea of time-restricted feeding is to reduce your just total eating. It’s a calorie control issue. I don’t have a problem with that, but I think that the two meals should probably be at least six hours apart. And again, how do you get in 150g of protein six hours apart? So 150g that means you’re getting in 75g per meal. We know that your optimal use of protein for muscle mass probably plateaus at somewhere around 60g. So you talked about excesses. There’s probably a limit to how much protein you can use at a single meal. And we think the upper end of that is probably 55 to 60g range.

Brett McKay: Okay. And so yeah. This would be below… Like if you’re an adult male or female, that’s not enough protein for optimal, right?

Donald Layman: Yeah. So if you’re trying to do weight loss, if you’re trying to restrict your calories, most of those people will probably be targeting 100 to 120g of protein per day. Distributing that in two meals of 55g is probably okay. But if you’re trying to be a bodybuilder with 200g per day, putting 100g in each meal is a really bad idea. You need to distribute that across three or four meals to optimize the effect.

Brett McKay: Speaking of weight management, is there any benefit of protein when it comes to weight management?

Donald Layman: Yeah. We’ve done a lot of research on that. And so two ways to think about it. One is we want enough protein to protect muscle. One of the problems of weight loss is what we call yo-yo dieting. People will restrict their calories, lose 20, 30lb and three months later they gain it back. Well, every time you lose body weight quickly, up to half of the weight you’re losing is muscle, is lean body mass. Somewhere between 35 and 50% it’s gonna be muscle mass. And so when you lose it quickly and then regain it, yo-yo back up, what you gain back is just the fat and you’ve lost muscle. So that makes it harder and harder to lose weight over time ’cause you’re losing your lean body mass. So the first reason we want to use protein is to try and prevent muscle loss during weight loss. We call it protein-sparing.

And we’ve shown that that’s very effective. The other aspect is when you’re trying to really reduce calories, what should you reduce? And most of the research shows that reducing carbohydrates is an important way to go. So when we add protein, we usually add it as a substitute for carbs. So we’ll add, whatever. 50 more grams of protein to a diet and replace 50g of carbohydrates. So we’re going to higher protein, lower carbohydrate diets. When we do that, we know that we reduce hunger, we increase satiety, we stimulate thermogenesis, the amount of heat you burn from meals, so you’re just wasting calories. And you also basically are sparing muscle protein loss. You’re correcting body composition. So there’s a lot of reasons to increase protein for weight loss. We know that it’s a highly, probably the most effective way to correct body composition and lose weight.

Brett McKay: So I’ve heard about this idea called the protein leverage hypothesis and I’m intrigued by it. What do you know about that? Can you walk us through that idea?

Donald Layman: Yeah. So Steve Simpson in Australia is a nutritional anthropologist. He’s actually a pretty good friend. He basically looked at the diet of humans, but basically all animal species. And he realized that basically all animals eat toward a protein target and it’s around 16, 17% of calories. And what his concept was… We look back in time and we realize that in the mid 1980s, all of a sudden we see this epidemic increase in obesity in the United States. And we start wondering why. And one of the things that happened at that point is people were so afraid of cholesterol and saturated fat. We developed what was called the food guide pyramid. And the food guide pyramid said eat a lot less animal products, ’cause that’s the way you reduce cholesterol and saturated fat, and eat a lot more grain products.

What that did was dilute out the nutrient density of the diet. People ate 40% more calories from grains. We diluted the protein down and saw the protein leverage hypothesis is is that for adults to get to the protein target, they had to eat a lot more calories. And that seems to be exactly what people did. They ended up eating 350 to 400 more calories. Our protein intake stayed about the same, but we ate 400 calories more to get to it. And we think, or the theory is that that’s the… Was really the origins of obesity epidemic. And so we’re now seeing sort of a shift back to people who are much more protein-conscious. People are trying to reduce the carbohydrate and we’re seeing some people at least having much more success in controlling body weight.

Brett McKay: Yeah. It’s really interesting and it makes sense. And I can see it with snack foods. A lot of the snacks they’re high carb, low protein. So people’s bodies are trying to hit their daily protein target, what the body wants, but they just keep eating and eating in order to reach it. And they eat through a lot more calories to get to the protein their body wants.

Donald Layman: Yeah. The food industry has done a great job of developing foods that are very savory. The body sort of recognizes them as that protein kind of taste and they’re very addictive. And so to your point, we’re seeing a lot more snack foods, a lot more high carbohydrate, grain-based products in the diet and people are getting too many calories. Most of the data suggests that obesity is really associated with snacking more than it is with meals. And I think that’s true. I think portion size is part of the issue but I think the calories we consume outside of mealtime are a huge part of the issue.

Brett McKay: And a way to counter that is be more conscious about the protein you consume. Be more deliberate about it.

Donald Layman: When we teach it for weight loss, we always teach people that anytime you eat, you have to focus it on protein. You have to make a protein decision first. And so you should never be eating anything that isn’t focused on protein. And it may be that you’re making a choice of eating some almonds for a snack or cheese or something, but you should always be protein-conscious. And likewise, when you’re starting a meal, we teach people that the first thing you eat at any meal needs to be the protein part. Your first bite needs to be a protein bite. So when they bring out the bread or the chips or while you’re waiting, you can’t eat that until the protein arrives because your body doesn’t recognize carbs really for satiety very well. The example I like is, okay, we all go out for dinner and at the end of the dinner and you’re basically full, if they bring out another steak, it’s totally revolting. You’re not gonna eat it. But if they bring out chocolate cake, you’re perfectly happy to eat it. We just simply don’t register carbohydrates in the same way.

Brett McKay: Well, Donald, this has been a great conversation. Where can people go to learn more about your work?

Donald Layman: So I’m on what used to be called Twitter with @donlayman. So I try and provide some science there. I have a website called and my colleague Gabrielle Lyon and I have a book coming out called Forever Strong, that will come out October 17th I believe, coming up. So new book, Forever Strong, I think will be a great piece of information for the general public.

Brett McKay: Fantastic. Well, Donald Layman, thanks for your time. It’s been a pleasure.

Donald Layman: My pleasure. Thanks, Brett.

Brett McKay: My guest today was Dr. Don Layman. He’s the foremost researcher on dietary protein. You can find more information about his work at his website, Also check out our show notes at, where you can find links to resources, we delve deeper into this topic.

Well, that wraps up another edition of the AOM podcast. Make sure to check out our website at, where you can find our podcast archives as well as thousands of articles that we’ve written over the years about pretty much anything you think of. And if you haven’t done this already, I’d appreciate it if you take one minute to give us a review on Apple Podcast or Spotify. It helps out a lot. And if you’ve done that already, thank you. Please consider sharing the show with a friend or family member who you think could get something out of it. As always, thank you for the continued support and until next time, this is Brett McKay, reminding you to not only listen to the AOM podcast, but put what you’ve heard into action.

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