Protein-Maxxing: Is It Actually Bad For Us?

- I have a confession to make. - I am, I am, (beep) - Whoa, I would never have thought I'd see the day. - Hi, I'm Wendy Zuckavan, and this is Side Spurses. (upbeat music) These days, protein is everywhere. It's being added to all kinds of foods from lattes to popcorn. Cottage cheese is flying off the shelves, and people are telling pulses, yes, I am actively trying to get more protein into my diet. And some of us are going hard. They are protein maxing. My protein talkers. - Hi protein enchilada pasta. - Five reasons. My protein is essential and wide more of it. - The house is film muscle. House to control our hunger. House to maintain a lean physique. And maintenance looks sex is (beep) High protein low calorie beef teriyaki summer rolls. - We still need more protein. - But just recently, we've been hearing something that is turning all of this on its head that suggests we are doing protein all wrong. Headlines are saying that we need to actually cut back on protein if we want to live long and healthy lives. The new research is challenging the high protein craze. Decades of data, animal studies and human studies, asking the question whether eating less protein can promote health through aging and help to extend your lifespan. - Low protein diets actually help you live longer. - So what is going on here? Should we be protein maxing or protein meaning? When it comes to protein, there's a lot of-- - We still need more protein. - But then there's science. - And if you have a friend who is guzzling down protein or just confused about what's the right thing to do here, understandably, share them this episode where on YouTube or wherever you get your podcasts. - Welcome back. Today we are digging into the science on protein and who else to give us that science? But meet head senior producer Rose Rimmler. - Hi Wendy. - Hello. I have a confession to make. - Do you, your protein maxing right now? Has we speak somehow? - I am adding protein powder to my yogurt. Whoa, I would never have thought I'd see the day. Trying to build more muscle and I got sucked in but now these headlines say, stop doing that Rose. I'm being vulnerable with you. - Wow, I can't believe you share something so personal. Thank you, I really appreciate that. You're not alone, that's not really that special of a confession, I think a lot of people are doing that. Which is why it was very surprising to crack up on the internet one day and see that now everybody's talking about maybe we should be doing less with protein instead of more. - Yes, I was so surprised when I'm getting these videos saying you study finds protein restriction is the way to go. So is the protein pendulum swinging? That's the question. And a lot of the headlines that are talking about this are referring to this one new paper. That came out recently. It's all about protein and lifespan. And I talked to one of the authors. His name is Dudley Lamming. - I'm a professor at medicine at the university. It was constant medicine. And I'm an aging biologist. - Not as in the creeks and pains of old age are catching up with him. - Yeah, yeah, I'm an aging podcasting. - You studies aging. - I've been studying aging for about 20, 25 years now. - This is exciting, though, because he is patient zero. He's the author that launched a thousand headlines about how protein restriction is healthy. - Yeah, I mean, kind of accidentally. I mean, that wasn't Dudley's intention when he wrote the paper. - I was quite surprised, it was originally written as an article for scientists by scientists. And so it was really interesting that it got so much attention. - 'Cause it turns out that scientists like Dudley have actually been studying protein restriction for a long time. I had never heard of it, but I was in the dark. This has been around for a while. And actually where this all comes from is, you know how there are studies in animals that find that calorie restriction can extend lifespan? - Yes, yes, of course, these are fasting. People might fasting diets that are also very popular right now. That all that research started off with animals. It's exciting, we'd studies in animals, little, little animals, the worms, the flies, they would put the board fasting diets and realize what they were living longer. So they have basically been doing the same thing with protein restriction all this time scientists. - More or less, yeah, because fasting or calorie restriction is pretty hard to stick to. So the idea here is like, well, actually, if we're seeing some of the same benefits from not reducing your overall energy intake, but just tweaking your macros so you eat less protein, then maybe this would be a lot easier for people to actually stick to. - And do they find that that in animals, if you restrict protein, they live longer? - Yeah, short answer, yeah. I mean, in a lot of organisms, mice and rats, primarily, but they've also tested it in fruit flies and yeast. - Do you know why you looked at me like that? - I was a yeast. Do you know something I don't know? - I'm just really trying to avoid saying animals like yeast. 'Cause it's not an animal. 'Cause it's not an animal, what is it? - It's a fungus. - It's a fungus. - And in these experiments, what scientists are doing is they're typically cutting the protein and the diets of these creatures, like in half, and then increasing either the fats or the carbs, so that overall they're eating the same number of calories. - Okay. - And in mice, Dudley says that they live-- - Up to 30% longer on a protein restricted diet, depending on exactly the conditions it can be anywhere from 10% to 30%. - You can see why that's exciting. Because if that translated perfectly to humans, that would be an extra like 20 years on our lives. - Yeah. - Yeah, yeah, for sure. If that translated to humans. - Right, and so back to this big study, I think I'd everyone all, a Twitter. - Yes. - It's not a new experiment that Dudley published. - It's a review paper. - Do you know I still roast after all these years? I see the headline, New Study Shows Protein Restriction, helps you live longer, and in my head, I'm like, wow, they did a study in 40,000 people, and they followed them, and they found that those who didn't need a lot of protein lived longer. And every freaking time you go to the paper, it's either a review paper looking at all studies or in some research in rats. - Yeah, you sweet summer child. - When will you learn? - But in some ways, depending on the review paper, this might be even more exciting, right? Because they're pooling together all of this research that we have from the past. - Yeah. - We're talking about a collector body of work, but depends any of the bodies in this study humans. - There are some human bodies in this screen paper. - Obviously there are no studies where scientists took, you know, 100 human babies randomized them to either low protein or more protein, and then followed them for 100 years and saw which baby lived longer, right? - Uh-huh, yeah. - Yeah, we do have studies where they put people on low protein diets for kind of a few weeks, to a few months, and seeing what happens to them, they can measure certain things about them. - So one that Dudley did, they got about 40 people, all these raw men, they were overweight. These guys were randomized to either go on a low protein diet or stay on their typical diet, which was high protein. - Uh-huh. - For the guys in the control arm, they, you know, live life as usual, while the guys in the low protein arm. - We found that they lost about a pound and a half a week, and their blood glucose went down by about 5%. - With the two groups eating the same amount of calories, it's just that the protein restriction group ate less protein. - No, here's the crazy thing. They are actually eating more calories than they had been before, and they still lost weight. - So what does Dudley think is happening here? - Okay, so here's what we know. We know that when you feed people a low protein diet, they make more of this particular hormone, and that hormone seems to have something to do with brown fat. Are you familiar with brown fat? - There's two different kinds of white fat. - White fat, brown fat. - Tell me more, what do we care about brown fat? - So brown fat is when you end up with a lot more mitochondria in your fat, mitochondria are powerhouse of the cell. They create energy, ATP fuel energy for the body disease. use. Yes, so what does that mean for this brown fat if it's got more mitochondria in it? Well, if your white fat starts recruiting more mitochondria, which are a little bit brown in color, that turns the fat from white to brown in a process that scientists very cleverly call Beijing. Causing them to essentially start producing more energy in the form of heat. And so the mice literally burn off additional calories as fuel and overall lose weight. Oh, okay, so you restrict protein in your diet or the mice restrict protein in their diet. They produce a hormone. And what's this hormone called? It's called FGF21. FGF, I understand why you didn't name check it. It's not one of the cool hormones. No, but it is cool because so to summarize what Dudley thinks is happening. One of the reasons why he thinks protein restriction might be healthy is because when you restrict how much protein you eat or when they do it with mice in a lab, you see an increase in that hormone. And then that starts recruiting mitochondria into your white fat, turning it into brown fat, and that increases the amount of energy in that fat, increasing the amount of heat, ultimately, increasing the metabolism. That's what we think. I mean, not all of those steps have been shown in humans. But I will say, I will say there's still more reason to be excited about protein restriction. There's this whole other thing that has to do with mTOR. Do you know what mTOR is? Are you familiar with that? Yes. This is a big in the longevity community. Yep, they're always trying to hack mTOR. Yeah. So walk us through what tell us what's mTOR. MTOR is an enzyme that coordinates cell metabolism. And the thing about mTOR is that it's kind of like a switch. When it's on, it tells cells to grow and that seems to be linked to aging. And when it's off, it seems to increase what's called autophagy. And money, you know, you know, all about this, right? From an old episode. I mean, it's one of my favorite processes in the body. And it is a way that your body replaces damaged cell parts. And what happens is that a cell will literally eat itself. That's what auto-fudge means. So to take this back to protein restriction, what are they finding? It boosts autophagy? It looks like protein restriction, at least in mice, tamps down mTOR, boosts autophagy. And that might be what's leading to this increased lifespan, at least in these animal studies. But then, there's something inside me that still can't believe that restricting your protein is a good idea, because have I just been so rely? I mean, don't we need protein, right? For muscles, for balance, it's super important. Yeah, not all scientists are hopping on board, the protein restriction train. And there actually could be a downside here. It could be dangerous to try to do protein meaning. Coming up next… Welcome back today. We're talking all about protein. If you have a friend slamming down the protein day after day, maybe send them this episode. Rose, room less senior producer at science vases, you promised me some more science on this protein restriction, saying that perhaps it's not good, and we can keep out protein powder. Where do we go from here? Okay, so this idea of getting really low protein is so different from what we've been hearing that I had to talk to other scientists for other perspectives. The first person I thought of was Stuart Phillips. He is an exercise physiologist at McMaster University in Canada. Stuart is not on team protein maxing. So right off the bat, I'll tell you that. In fact, last year, he actually wrote a piece saying that this whole protein craze has gotten so out of hand, and he actually titled that piece. 2025 was the year that protein jumped the shark. An expression that kind of got him roasted by his family. My son was like, "What is this shark thing?" And I was like, "Well, there's this guy, his name is Arthur Fonzer-Relli, and he was the Fons, and he once jumped over his shark." And he was like, "What are you talking about?" So what does that mean? I was like, "Well, it was where the show really went downhill." And he was like, "That doesn't make any sense." But it's very pressing it because in 2025, he predicts that protein is going to go downhill from there. It's like happy days. And here we are in 2026, headlines saying, "We've gone too far." But he said he's not on team. He's not on team protein maxing, but he's not on team protein meaning either. So even though we think we've got a little overboard with our protein, he doesn't like those headlines that came out recently about how we all need to cut back and restrict our protein. Yeah, we ran some of those headlines by him. Surprising new study links low protein diets to healthy aging. Eating less protein could help you live longer. What do you think? Yeah. Well, all of the titles you read would have been reduced protein, helps you live longer, comma, if you're a fruit fly or a mouse. But you did, there was some human studies right. There was at least that one that you told me about. Yeah, I mean, Stuart's issue with that study was that it was short and not, you know, you can't really extrapolate from like a 12 week study to what's going to happen over an entire lifetime. You know, 12 weeks out of a year that has 52 weeks out of a life that is 84 years, you know, you can do the percentage. Another problem with the study, the menus of the people, you know, in the study were pretty different. So on the protein restricted arm, they were eating like a Mediterranean style diet. Lots of fish and leafy greens, whereas the other diet was like ribs and hot dogs and hamburgers. So there's a lot different about that diet than just protein content. And then that's they found all these benefits. Yeah, and the benefits aren't too surprising. The calorie thing and losing weight is surprising. But like the other stuff, like that would be better for you in other ways is not surprising. Given that they're eating a much healthier diet, even if you forget about how much protein they're eating. That's that's reason to be skeptical. Okay, so we don't have many human trials really putting this to the test. We don't have long-term studies, true for many things. Okay, but I guess you promised danger. Yeah, that's why we call you rose danger. Well, one of the reasons that Stuart is skeptical as he is is because there's reason to believe that going quite low in protein could be bad for you. Because as we age, we get worse and worse than incorporating the protein that we eat into our muscles and lose muscle mass. And so for older people and these are the people who are probably like thinking about like how how can I accept my my lifespan. They're the exact group of people who probably shouldn't be going low in protein. I think that those folks are in or are going to be in trouble. So they will lose muscle, they will get weaker, their risk for frailty goes up. And that's where my mom is right now. So I care about my mom. If you cut down your protein and you're not getting enough to replenish your muscles, you could end up with something that's called sarcopenia, which is like not having enough muscle mass and being really frail. So this is what we've known for a while. Protein is important for building muscles. So you need to get enough of it. Yeah, and if you don't, I mean the sarcopenia thing, it is a pretty big deal. We know that people who have sarcopenia, they are more likely to have falls. They're less likely to be able to be independent, eat, get dressed, go to the bathroom by themselves. And they're more likely to die like four times more likely compared to people of their age who don't have sarcopenia, according to one review. And it's not only that though, like there's this whole other thing we have to think about when it comes to low protein diets. It could really mess with your immune system. And this goes back to the whole MTOR thing we were talking about before. So, you know, the low protein diets seem to suppress MTOR. That also suppresses your immune system. And we know that because there is a drug that people will take, these longevity hackers, called rapamycin. That's right. Yes. That drug is actually, it's approved as an immunosuppressant. That's what it's actually for. And they give it to people who get organ transplants to tamp down their immune system. So that's the side effects that can happen if you're taking rapamycin, maybe a side effect that could happen if you're going low protein and tamping down your MTOR. You might be also tamping it down so much that it messes your immune system. And that wouldn't show up as much in the mice studies because the mice aren't really exposed to a lot of pathogens or in these like clean sterile cages and labs, right? But in the real world, we're out in society. getting rubby. And we actually have some signals in other places too that this could be a problem. So like I found this very small but very interesting study. They got 12 elderly women. Half of them were on a low protein diet, like really low. The other half more normal. And they did stuff to them like they tested their immune response. They exposed them to certain antigens and then saw like how well their body kind of responded to it. Okay. Antigens like tetanus, streptococcus, diphtheria, tuberculosis around. So what happened? So the people on the low protein diet they didn't mount as efficient or as good of an immune response as the people on the adequate protein diet. People that are on low protein and takes have lower levels of immune markers and immune function. And that's something that Stuart and Dudley agree on. Dudley being the the person that did the you know the big review paper we talked to earlier. Yes. He brought up a lot of these same risks and he is like this diet is not ready for prime time. So this isn't a diet that we're advising anybody to eat right now. So does Dudley restrict his protein? No, he says no he doesn't he doesn't do it. No, not even he does. No. So this leads us to the very obvious question of when it comes to protein. What the hell should we be eating? Okay. So out in the real world when you ask people what they eat and follow them over time, you get their food diaries, left to their own devices. People eat about between 10 to like maybe 25% of their total calories come from protein. Without even trying or thinking you're probably in that range. Yes. Does it make a difference if you're in the higher range versus the lower range? What do we know? So we have loads of studies looking at that. They follow people eating this normal range. They look at the lowest protein years. They compare them to the highest protein eaters. They look at stuff like cardiovascular disease, cancer, death from all causes. And when we look at total protein intake, we don't see a clear signal that higher protein is worse and lower protein is better or vice versa. This is how Stewart puts it. It's effectively neutral. In other words, there's no good or bad. But then how does this make sense with that study, the small study of women that showed when they were restricting their protein, it was affecting their immune system? Because in real life, people are very rarely getting too little protein by accident. You don't have to take protein powder to meet your minimum needs. You go out on the street and pull anyone off the street in New York City or if you went outside your studio and pulled anyone off the street in Melbourne, they're almost certainly getting enough protein to meet their basic needs without even trying. The one consistent thing we do see is that the source of the protein matters. So if you're getting your protein mostly from animal sources, especially like red meat and processed meat, that's associated with some worse health outcomes. It certainly does point towards plant-based proteins as a potentially healthier source of protein. Okay, so then I think my last question is just about protein maxing. So in these studies, you just talked about where people are kind of eating in this general range of what was it 10 to 25? Maybe 25, yeah. Percent of their diet and I'll go and overboard. But now with this new trend, people are really spooning the protein in, which I like you. Some sprinkling. I'm just sprinkling. Is this bad? Is it bad? Because this is a new trend. It wouldn't have been captured in those studies you're talking about, right? I don't know what the protein maxers are doing in terms of like the percentage of their diet coming from protein. If it's higher than 25%, they're kind of a known person's land in terms of the science. We don't really have many studies on those. Here's what Stuart said about that. We're conducting the natural experiment in real time. Call me back in about 10 years and we'll see whether this is playing out poorly or well for most people. So we don't really know if there's going to be a downside for people going really hard on the protein. But what we do know is that they don't need to. There's this meta-analysis that looks at studies where people they give people a ton of extra protein and have them hit the gym. Not average, the gains they got were like a quarter of a pound of muscle, like spread out through their whole body. So like tiny little gains from eating a bunch more protein. You just don't need it. And in fact, Stuart in our last episode about protein, he told us how he did these experiments where you collect, you feed people a certain diet and do you remember this? You collect their fingernail clippings in their pee and their poop and you look for the night in the period. That was quite visceral. It turns out that you just excrete what you don't use. Yes. Maybe you're not harming yourself. Wendy, with your protein sprinkling, but you might be wasting your money because you might just be peeing it out. I mean, also, this is why I'm least sprinkling because I look at the ingredients of it. In 70% protein, 30% absolute crap. This is a boi gum, a mulls of eyes. It's all this ultra-processed crap. Yeah, Stuart brought that up too. He was like, you know, a lot of that stuff is basically junk food, like protein bars. That is a franken food in terms of ultra-processed ingredients crushed together as a bar. I get it. They're tasty. Everybody goes, well, they taste so good and I'm like, yeah, sugar, a little bit of fat, a little bit of protein, blended all together. I had a chocolate one the other day and I was like, I think this is a candy bar. I know. It's a dressed up candy bar, but if I have my choice, we should all just have a piece of chocolate around three o'clock every day. Doctors orders. Got to have you through a clock chocolate. Hey. It was a fancy reference. You got it? Yeah, I mean, it's been a while since I had access to Nick a night, but I think, but I think that is what the fonts did. Hey. All right, Rose, you changing your diet as a result of all this research? No, I'm not protein maxing. I'm not protein minning. I haven't really changed a thing. That's a result of all this. So much research. So so many papers that you've read to not change a thing. That's pretty good. The big question, Wendy, are you going to keep sprinkling on that protein powder on your yogurt? No, I'm not. I'm not. I'm not going to no protein minning for me. Yeah, but no, I'm good. I mean, yeah, I was doing it just in case, just in case Rose. That's it. Get your, with the just in case. I don't need the just in case. No, I'm glad we had this talk. Yeah, that's science facets. How many citations are in this week's episode? Oh, um, this week there are 41. 41? And if people want to see them in all of their glory, where can they go? They can click on the link to our transcripts, the citations are on the transcript, and they can find that link in our show notes. Cool. Bye. Bye. This episode was produced by Rose Rimla with help from Meryl Horn, Michelle Dange, and a Kedi foster case. We're edited by Blitz Terrell. Wendy Zuckerman, me, I'm the executive producer, fact-checking by Marlo Staling, video editing and sound by Bobby Lorde, music written by Boomi Hidaka, Peter Lennon, Emma Munga, and Bobby Lorde. Thanks to the researchers, we spoke to for this episode, including Dr. Edward Giovenucci, Professor Holly Brownborg, Professor John Speakman, Dr. Min Yang Song, and Dr. Jessica Bisekersky. And an extra thanks to Humdinger Studios in Melbourne and Wolf Island Studios in New York City. Science Versus is a Spotify Studios original. You can listen to us for free on Spotify or wherever you get your podcasts. You can also find us on YouTube, TikTok and Instagram. So please come and say hello. I'm Wendy Zuckerman, back to you next time.