How Much Protein Do You Need? Top Scientists Still Disagree

How much protein do you need? A person trying to avoid deficiency is asking one question, an older adult trying to preserve function is asking another. So, is an athlete recovering from training, a patient recovering from illness, or someone losing weight, for example, while on a GLP1, trying to retain a lean tissue. One size doesn't fit all. Depends on age, physical activity. It also depends on personal preference. Protein is still heavily debated. Even amongst the best and the brightest. The one thing that they agreed on is a- I'm Dr. Gabrielle Lyon, and I'm a physician. I am fellowship trained in nutritional sciences and geriatrics. I'm also board certified in family medicine, and I've been studying protein. I don't know for the last 20 years, and protein is everywhere right now, and thank goodness. It's in coffee, cereal, cookies, chips, shakes, snack bars, you name it, walk through almost any grocery store, or who knows, even a home depot, and you'll see products competing over who can place the biggest protein number on their package. And here's the strange part. Despite all of the confidence that you're seeing in the marketplace, protein researchers are still debating. Some surprisingly basic questions. I was at the Protein Summit 3.0 at Texas A&M in college station, and let me just tell you, it was so much fun. Yes, exactly right. No one wants to hang out with me on a Friday night because we'll be talking about citrally. But the reality is that protein is still heavily debated, even amongst the best and the brightest. A recent research symposium brought together established scientists, early career researchers, and representatives from several food and agricultural organizations to wrestle through these questions. And their conclusion at Protein Summit 3.0 wasn't that protein is good or bad. It actually was more interesting than that. I mean, who surprised? The one thing that they agreed on is that protein is essential. But its effects depend on the amino acids involved, the person eating the diet, and also the rest of the diet. Today we are going to pack just a little bit of what that means. First off, protein is more than building material. We usually hear that protein builds and repairs muscle. That's true, but it is only part of the story. When we eat protein, the body breaks it into amino acids. Those amino acids help make tissues, enzymes, hormones, neurotransmitters, and immune compounds. They also act as signals that tell ourselves what to do. Unlike body fat, however, the body doesn't have large storage tanks for extra amino acids. Every day, the amino acids we consume must be incorporated, transformed, oxidized, or otherwise metabolized. The word oxidized sometimes sounds negative. It can make it seem like the body is burning and wasting valuable protein. But that interpretation is just too simple. Amino acid oxidation can be part of the body's regulatory system. It can activate signals, support energy metabolism, and produce compounds that are needed elsewhere. So the question isn't merely, did this amino acid become muscle? Because basically out there in the landscape, people will eat protein and think, okay, well, this becomes muscle. It's not really that. The better question is, what useful job did the body assign it? There are four major amino acids. I mean, there are many. There are 20 different amino acids, nine of which are essential. But to understand this broader role, consider four examples that were discussed at the symposium. The first, this is methionine. Methionine contributes to the production of compounds such as glutathione, an antioxidant that helps the body respond to metabolic stress. It's also called the master antioxidant. Glutathione levels can decline with age, which raises the possibility that protein quality and intake could affect resilience in older adults, which I find fascinating. The second example, phenylalanine and tyrosine. These amino acids are connected to dopamine production. Dopamine is involved in motivation, mood, attention, and movement. Now, this does not mean that eating more protein is a simple cure for a low mood or for a concentration, but it does show that amino acids participate in brain chemistry as well as muscle biology. Again, why is this so fascinating? Because universally, we think about protein as just one thing, rather than its constituents. Third, three-anine. A large portion of incoming three-anine is used by the gut, included for mucin production, the protective mucous layer lining in the digestive tract. That means an amino acid can be important before it ever reaches the rest of the body. Mucin production is really important to protect your digestive lining. So, researchers know relatively little about how dietary protein affects this system in humans. And the gap matters because conversations about gut health usually focus on fiber and the microbiome, not on protein. Last but not least, there is my favorite and that is lucine. Lucine is widely associated with muscle because it helps activate emtore, which is a signaling pathway involved in protein synthesis. But lucine also interacts with insulin release, fatty acid oxidation, glutamine production, and other metabolic processes. The important lesson isn't that everyone should immediately go take lucine supplements. It is that individual amino acids have individual biological rows. Treating protein as one undifferentiated nutrient can hide that complexity. Okay, so this is the age-old topic, conversation question, minimum versus optimal. That leads to the most controversial question, which is, believe it or not, how much protein do we need? The familiar adult recommendation is said at about 0.8 grams per kilogram of body weight per day for a person weighing 70 kilograms, about 154 pounds, that works out to roughly 54 grams of protein. What does that number mean? Well, it generally is interpreted as an amount intended to cover the basic needs of most healthy adults. It is not necessarily a universal target for every possible outcome. Imagine this, a room full of the 100 most influential protein scientists. And they were arguing about this topic. And one of these topics was between a minimum adequate intake and an optimal intake for a particular goal. So is an athlete recovering from training, a patient recovering from illness, or someone losing weight, for example, while on a GLP1, trying to retain lean tissue? One of the speakers argued that a number of metabolic outcomes appear to improve somewhere around 1.1 to 1.6 grams per kilogram per day. This should not be heard as a new universal prescription. The symposium participants were clear that the evidence is not strong enough to replace one simplistic number with another. Instead, it points towards a range shaped by context. The future may involve population categories based on a life, stage, physical activity, and health status, rather than one precise recommendation for every adult. So I don't know about you, but this blows my mind, right? Think about this, that a 60-year-old postmenopausal woman would have the same dietary protein recommendations as a 35-year-old guy. It's not the same. And especially if the individual amino acids, those needs change. So perhaps a truly individualized protein prescription based on genetics, or detailed metabolic testing. I mean, I know that that's more aspirational for now, but I do think eventually it's going to become realistic. The other thing that this group noted is that the evidence has blind spots. Why don't researchers already have better answers? One reason is that some of the evidence underlying broad recommendations comes from narrow populations, particularly healthy younger men. It is risky to assume that those findings automatically apply to older adults. Women at different life stages, like I mentioned, children, athletes, are people living with chronic disease. One of the panelists noted that an influential body of evidence included remarkably fewer older adults, and that doesn't make the research useless, it means that it has boundaries and limitations that should be acknowledged. Researchers also face a methodological trade-off. What does that mean? Well, highly controlled laboratory studies can isolate mechanisms. Scientists can control meals, which, by the way, I packed and handed a bunch of those out. They can measure amino acid metabolism and determine what happens over several hours or days, even weeks. People do not live in metabolic wards. They just don't. I mean, not last time I checked. Free living studies reveal whether an intervention is practical and sustainable, and they include the messiness of appetite, schedules, budgets, food access, children, culture, and personal preference. The panel rejected the idea that one approach is inherently superior to others, which is a pretty big deal. This room full of the most elite scientists said that control studies and real world trials answered different questions and that they should inform each other rather than ranking the hierarchy of evidence. A laboratory study might tell us whether an intervention can work a longer real-world study helps reveal whether it does work when people have to live with it. Which again, it's so interesting if you sit down and you talk to scientists and you'll ask them about their paper and then you ask them to bridge the gap to real-world, it doesn't mean that the study was designed to do that. Give a rigor is possible in both controlled and free living research but one paper, one randomized trial can never be the answer or give an answer. It's a totality of evidence. Another thing that the protein working group talked about was why one size doesn't fit all. One of the strongest themes from the early career panel was context and this is the up and coming younger scientists. For public health guidance, broad recommendations are necessary. You cannot give millions of people a personalized metabolic assessment, even if we'd like. But clinical practice is different. Someone recovering from surgery may have different needs than a healthy office worker. An older adult with low appetite might face different challenges from a young athlete eating far more protein than necessary. So this distinction resembles the difference between public, physical activity guidelines and individualized training plans. We can make broad generalizations but that's very different than an individualized training plan. The general guideline helps move the population in a healthier direction. The prescription helps a particular person solve a particular problem. An in protein research the most promising near term opportunity may be better guidance for clinical populations and life stages were preserving muscle and function is especially important. Science is not yet precise enough to create a perfect number for every person. But it may be precise enough to stop pretending that everyone is the same, which is the biggest thing. People always ask me, how much protein do I need and I say, well, depends on age, physical activity, it also depends on personal preference. Another thing that came up was the protein fortification problem and we should talk about those protein cookies and coffees because frankly I love all of them. But protein fortification is one of the fastest moving parts of the food marketplace. And one of the least understood scientifically, adding protein to a product can be useful. An older adult with a low appetite might struggle to eat enough, a teenager with a packed school and sports schedule may need something convenient. Like my kids, we eat the David Bar at home all the time, shift workers or people with limited food access might not always have a complete meal available. This is where shakes and beef jerky can come in. A fortified product can fill a legitimate gap. But protein can also create a health halo. A drink containing 20 grams of protein may still contain 50 grams of added sugar and calories. A protein snack may be super high and dense in calories, but also have protein. So adding protein doesn't cancel the rest of the nutrition label. It can also be some displacement, which you're like displacement. What is that? If we just hyperfocus on protein, for example, if athletes reportedly consume far more protein than recommended while they fall short on carbohydrates, iron, calcium or vitamin D, the issue isn't simply that protein intake is high. It's that the dietary pattern has become unbalanced. So this gives us a practical rule, number one, never evaluate a food solely by its protein number alone. And I'm like, wait, what is she talking about? Doesn't she love protein? I do. But what else comes with it? Look at what replaces it and look at whether it solves a nutritional problem or potentially creates one. I remember, I ate tons and tons of egg whites. So that's all I was eating. I think it was in college. And I ended up giving myself a biotin deficiency. Because there was a binding component in these egg whites that I was eating and it bound all this biotin. So while I was solving for my protein problem, I was creating other problems. And listen, a protein cookie might be useful in one context, like it takes delicious and potentially unnecessary in another where you're overeating a protein cookie when you really just need some fruits and vegetables. Another reoccurring message was that protein doesn't arrive by itself. What does that mean? It comes in beans and lentils, soy foods, dairies, meats, fish, eggs. I feel like I'm on trivia, but you get it. It comes in a whole food matrix. And each source of protein brings a different food matrix and a package of nutrients. That makes isolated comparisons difficult. So you can't compare fish to the protein in beans or beef, really, to the protein in fish, per se, because it's not just about the protein, it's about the whole food matrix. And researchers want to understand protein quality and bioavailability, but they also want to understand how protein containing foods operate within a complex dietary system. And I think that this is really the future of what we're going to see in nutritional research. And the public doesn't eat amino acid charts and no one's talking about them Friday night unless you're at my house, but they do eat meals. And future research must ask not only whether one isolated protein produces a short-term response, but also what happens when it is part of a realistic diet over time. What food does it replace? What nutrients accompany it? Can people afford and prepare it? Do they even enjoy eating it? And will they continue to eat that way six months later? Scientists and price often shape decisions before health claims do. Nutrition guidance that ignores the reality is unlikely to change behavior. Another thing that was discussed was why collaboration is so difficult. Good protein research is expensive and difficult to coordinate. Large, multi-site studies can recruit more diverse participants and harmonize methods across institutions. They may be especially valuable for studying populations that are difficult for one research center to recruit. But collaborations, for example, if WashU wants to collaborate with Harvard, this involves a contract, data systems, competing timelines, institutional rules, and decisions about funding and publication. Food industry and commodity organizations express interest in collaboration with dietary pattern research, bioavailability, and better methods. And one of the sponsors at this group described plans to require raw data sharing in new contracts to improve transparency and reproducibility. This means that we could have industry involvement that could strengthen trust particularly because food industry-funded nutrition research is often viewed skeptically. And that was also really surprising with these researchers is that research is really expensive. And everyone in the room acknowledged it that it was expensive and it was complicated. And that scientific ideas operating under different contracts and funding rules just becomes really challenging. One potential solution that they had talked about was to combine federal funding with multiple industry partners and you study designs that compare several dietary patterns or protein sources at once. This means if you are someone who's really interested in science and you see industry funding a study doesn't mean that it's bad. The bottleneck is typically the infrastructure needed to then go out and do these studies. Where does the field go from here? Well first, researchers want to study more diverse populations rather than continuing to generalize from young healthy subjects, right? The majority of research is done in young healthy males. Second, they want to connect short-term mechanistic studies with longer real world outcomes. And third, they want better standardization. When studies define foods, protein exposure, and outcomes differently combining the evidence becomes difficult, which goes to one of the other solo castes that I talked about. We have to have a unified language for talking about things otherwise, you know, someone is talking about their favorite protein and how fluffy it is and the other person is imagining a marshmallow, whatever it is, but we have to have a unified language. And fourth, they want to investigate protein as part of complete meals and dietary patterns. They want more evidence about fortified foods, including who benefits and what nutritional trade-offs that they create. For example, if you do what I did and have a loose egg white diet only, you might also get a biotin deficiency. Thank you very much. And finally, they all want clear communication. Scientists deal in caveats and uncertainty. Public communication rewards simple claims. You and I both know that. Scientists hedge what they say, where public in terms of what is out there on the internet, the simple claims are the ones that are grabbed on. And the challenge is how do we simplify universally without distorting the accuracy. For example, more protein is always better, the quote, the saying, but it's inaccurate. Or another saying quote, protein doesn't matter because most people avoid deficiency. That's also too simple. A more reasonable message might be the following. Get enough protein from varied sources, balanced dietary pattern, and recognize that your needs may change with age, activity, and health. So in closing, there is a lot for us to learn, but the one takeaway I is this. Protein is not simply one single number. It's a collection of amino acids that each do various things within the body and that the amount and the kind of amino acids that we need depend on our age, our activity level, what we're eating in totality. And we have a lot more to learn, but the current recommendation provides a useful baseline. But remember a baseline is not the same as ideal for every person in every scenario with every goal. And at the same time, the excitement around protein is amazing and it should not persuade us to judge every product by how much protein it has by understanding that sometimes extra protein is helpful. Sometimes there's an added cost and sometimes it's actually distracting from what the overall diet is missing. The future of protein science probably won't produce one perfect number. So forget it, it's never going to happen. But what it will do and what I'm really excited is that it will produce better questions. For example, who is this protein good for and what is the outcome and from which foods and what about the food matrix? And these questions, I know I'm so sorry, they're less catchy, but that doesn't mean that they are less relevant. Till next time, I'm Dr. Gabriel Lyon and don't forget to stay forever strong.