Is My Metabolism Just Slow?
In this episode, we're diving deep into a topic that ties into everything we discuss: metabolism. We're breaking down this often misunderstood concept and answering some of the most common questions—like, does metabolism really slow as you age? And why do some people seem to have a "faster" metabolism than others? Whether you're curious about boosting your metabolism or just want to learn more, this episode is full of tips and facts you won’t want to miss!
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Juna Since we've been doing this podcast for a long time, we have covered a lot of topics.
Eddie And there are certain topics that are just really popular.
Juna And a lot of these topics are complicated, but they relate to everything we talk about. And one of those topics is metabolism. Oh boy. Eddie. Oh boy is right. Because metabolism is such a complex subject and it's been giving scientists headaches for decades. It has been giving me personally a headache for two decades. Okay.
Eddie All right. You know, before we lose the listeners in the first 30s of this podcast, I think we're going to do something that we're actually good at, okay. Which is take this admittedly complicated topic. Yeah. And break it down.
Juna Well, we're going to break it down. But did you know that we are a science based, humor laced health podcast? So I think we're also going to make it fun.
Eddie Yes, we're going to make it fun as well, because I mean, we're going to answer things that listeners ask us like, I my metabolism is slowing down or I just don't have the metabolism I used to.
Juna Or if you're like me, you're like, why is her metabolism so fast? Why is my metabolism so slow?
Eddie So we wanted to start a series will recover the fundamentals, the key concepts, the big rocks, the tie, everything else we talk about together.
Juna So on this first ever episode of the series, we are diving into the fundamentals of metabolism. What is our metabolism? Do some people have a slow one and other people have a fast one? How can I speed mine up asking for a friend? I'm unit yada.
Eddie And I'm Doctor Eddie Phillips, associate professor at Harvard Medical School.
Juna And you're listening to food. We need to talk, the only health podcast scientifically proven.
Eddie To speed up your metabolism.
Juna Do you? That's right. That was my line, Eddie.
Eddie Oh, sorry.
Juna First, let's take a moment to shout out one of our favorite reviews of the week. Eddie, do you want to do the honors?
Eddie I would love to, and I can't imagine how you chose this one unit because it says these two are the best and it's from a MLB 22. Sounds like.
Juna A lot of what is good.
Eddie For. I don't want to describe that, but they stand for. Or they just may want to remain.
Juna Send us an.
Eddie Email Lby 22 first. Thank you for your time, effort, and of course, energy.
Juna Oh.
Eddie With an exclamation point.
Juna Oh!
Eddie Speaking of energy, this amazing podcast has helped me learn about more ways I can increase my energy.
Juna Oh, happy.
Eddie To say my energy has been up up, up and my quality of life has improved too. Thank you. Oh, isn't that sweet?
Juna Awesome!
Eddie I think it's a great way to start the episode. My energy is up and I think people are going to hear about why this is such an important thing. We're going to talk about energy.
Juna Yes, it's so relevant to today and metabolism.
Eddie I mean, that was intentional.
Juna And your heart put it together to be honest. But now I did put it, guys, let's pretend I did. Okay, guys, you know, I totally did that on purpose. That's totally why I chose I because we're talking about metabolism today.
Eddie And you were choosing from almost 2000 reviews to find this one about energy. I think we're just about a 2000.
Juna 1,000%, 1,000%. Okay. But before we get to that, I just have one quick announcement to make. So we asked on our membership what you guys wanted from us next. And one of the most highly requested things that people said was a food we need to talk newsletter, right?
Eddie We cover a lot of complicated topics on the show, so people have been asking for years, can you kind of like, write it down? Give me the CliffsNotes. I just, you know, I was listening, I was laughing, it was fun, but I need some notes. So let's put together the studies and the take home all together in our newsletter.
Juna So we finally did it, guys. And basically whenever we come out with an episode, we're going to be sending you an email, breaking down the episode, linking to the studies, and giving you the bottom line for everything that we talk about. So right now you can go to food. We need to talk.com/email to sign up.
Eddie And now let's get to the episode.
Juna So when we were thinking about topics to discuss, metabolism was one of the most requested topics because obviously it's very complicated. There's a lot of science that goes into it. And honestly, it's been giving researchers headaches for decades. Like, we have really struggled to understand something as complicated as metabolism. But before we jump into the science, Eddie, I just wanted to know about your own personal relationship to your metabolism.
Eddie Oh, you mean when I was, like, in my young 30s and was a new dad and a new practice, and I was eating like I was much younger and much more active?
Juna Yes, exactly.
Eddie And how my weight was going up like an average American, about 2 pounds a year. Is that what you're asking about?
Juna Yeah.
Eddie And I finally showed up at the doctor's office at about age 35 years old. Now, this is a big deal for a doctor, because I don't know if you know that a lot of doctors, the doctors they see are their friends in the hallway or their medical school.
Juna Do doctors not see a doctor?
Eddie We need to be better at that. And I finally show up and I figure it out. First off, congratulations. Hello. You know, I take care of me, and I'm in okay shape. I'm a little tired, a little stressed out. A little less exercise than I used to get. And the subject comes up about my weight, and I asked the doctor, how much should I be gaining each year? And he looks at me, holds up his hand in a big round zero. It has this. No no no no. Yeah. He's looking at me like. And where did you go to medical school. Like. And then he gently explained that I really should not be gaining weight, that something has changed. And I really thought, well, it's just that my metabolism has slowed down. There's more to the story and I think we should get on to that.
Juna Okay. Well for me I felt like first of all you know how we talks about like oh when I was young I could eat whatever I want to. I'm like, well I have never had that. I don't know where everybody else got that. Like honeymoon period in their teenage years and 20s. I never had that. I always felt like I had to be careful about what I eat. And I also had two sisters, which we talk about this in the book a lot.
Eddie We still have them.
Juna I still have them, yes. Thank God I love my sisters, too, that they're the best. But my sisters have always been very skinny, so they just had a very different body type than I did. And I was never overweight as a child, but I just wasn't stick skinny the way it was like very in fashion to be in the.
Eddie Like, they were really skinny and eating or just skinny.
Juna Were skinny and eating. I felt like like I felt like they were never, you know, when we go to birthday parties and stuff, I would always be like, oh no, like, I don't want any cake. Or when we have like a pizza party at school or something, I'll have one piece. And my sister, I remember she went through a phase where she was like, I'm going to try to eat five today. Like she was like, really? And she had such a big sweet tooth and all these things. So I just remember my family always saying, oh, she just has such a fast metabolism and me always thinking like, damn. Like, I guess some people can just eat whatever they want. Other people can't. And also all the women I knew in my life, they were always complaining about their metabolisms. And I'm sure men did this too. But maybe I just interacted more with women. Like a lot of my teachers were women and my piano teachers and stuff. And so I remember them saying things like, oh, you know, back when I was young, I could eat whatever I want, enjoy it while you have it. And I was like, lady, I don't even have that. So I'm like, I don't even know you're talking about.
Eddie So maybe like an infancy or eating whatever you wanted enough.
Juna To, I guess so, but yeah. So I just thought it was like this magical word that kind of explained why some people struggled with their weight and other people didn't. And that's kind of all I knew about it. Lo and behold, guys, it is not a magical concept. It's actually a biological thing that happens in our bodies. And that is what we're going to talk about today. And the first thing we need to tackle is that there is a lot of jargon in this episode, okay? There's gonna be a lot of words and acronyms. And so we're going to try to do it in a fun way. That's not confusing, but.
Eddie I'll keep on yelling out jargon alert. Yeah. No, seriously, what we're talking about and you and I have already brought up two topics that we need to cover. One is does your metabolism really slow as you age and what will cover that? And also, is it that one person has a faster metabolism than another? Can you blame it on your parents? Or is there more to it? So let's get to some of the definitions. The first one, I like how it defines itself. So I'll just say it is your total daily energy expenditure.
Juna Right. And this is if you look up in papers, if you're trying to find papers about metabolism, they're not going to talk about metabolism. The way we talk about it, they're going to talk about total daily energy expenditure. And that's because metabolism can refer to so many things in the body. So there's papers on like carbohydrate metabolism, alcohol metabolism, protein.
Eddie Metabolism, it all works differently. And that's why scientists need to be a little bit more specific. So let's if we say TDE is going.
Juna Right so we can just break it down right. Total daily the total energy in a day energy expenditure that you're spending right. Expenditure is spend. So it makes sense. It kind of defined itself like you said. But it is definitely a lot more of a mouthful TDE we're not going to we're not going to say, oh yes, my total daily energy expenditure today is really high because I did it. You know what I mean?
Eddie So forgive us when we just say metabolism. We're thinking TDE total daily energy expenditure. So let's start off, you know, we're going to give you up for the next 24 hours. Here's your job. You have to lie in bed. Breathe. Keep your eyes closed. Oh, Instagram. Nothing. You're not going to eat. You are not going to go to the bathroom. We'll figure out something there. We're just going to keep the lights on so you can.
Juna You're going to stay alive for 24 hours.
Eddie You're going to breathe. You're going to digest anything that's in there right now. You're going to pump your blood, grow some new skin cells. Your hair is going to get a little bit longer, but you're not going to do anything else. Yes, that's going to be at your base, your basal metabolic rate.
Juna Boom. So your basal metabolic rate guys is the majority of your metabolism. So over half and it depends on the person. It can be 60 to 80% of the total calories they burn in a day is just their basal metabolic rate, which as Eddie said, is just the energy you spend keeping the lights.
Eddie On. And if a bigger person is keeping on more lights and actually pumping more blood, and is just playing bigger and growing more skin and has more muscles to keep up their basal metabolic rate measured in, we're going to get to it. Calories is going to be higher.
Juna Right? So intuitively, you probably have notice that it seems like bigger people can eat more than smaller people. And that's just going to be true in most cases. Just because the bigger person has a lot more cells, they have a lot more tissues. There's just a lot more upkeep that has to happen, which is why they can often eat more calories. And we should also say that this is also often true why men seem like they have higher metabolism. Some women. It's also because men are often, on average, larger than women, right?
Eddie So after lying there for a number of hours, being perfectly still, because you'll be so compliant with this and you haven't eaten and for God sakes, no Instagram. And then you whispered to me.
Juna Can you get me something to eat?
Eddie And I bring you. It really doesn't matter what. But I bring you 500 calories. I bring you a thousand calories.
Juna Okay? Yeah. I'm hungry.
Eddie Yeah, yeah, yeah. I mean, we've been at this for a while, and I bring you a thousand calories to eat because you're making up and that. Okay. What's really cool is that it actually takes energy to eat the well, to eat the food and digest it. So that is the thermic. Thermic refers to heat effect of food. Right. So I give you a thousand but it's going to cost you. What do we say like 10 to 15%.
Juna Yeah. Yeah.
Eddie Okay.
Juna To break it down. So. Okay. You know how we always talk about on the show. Remember we did our sugar episode. We were talking about how, like, oh, yeah, you got these, like, you know, all these molecules strung together and starches, and that goes into your stomach, and then your stomach has to break it down into, like, singular glucose molecules, and then they go to the bloodstream and all these things happen. And similar things with protein make protein is even harder to break down than fat and carbohydrates. So obviously it's a lot of work for your body to try and the food that you eat into, first of all, energy. And then second of all, what comes out the other end. Right? Like there's a lot of things that happen in between. And all of those things take up energy. And that is what Eddie's talking about. It's the thermic effect of food. So that's the second component of metabolism.
Eddie And it sounds like you're getting a discount, right? Like, oh, I did a thousand calories, but it cost me 150 to digest it. So therefore I'm only, you know, up 850 calories. But in the end, it really doesn't add up to that much. Because even if you eat, you know, 2500 calories, right? Probably more than you need, 3000 calories. You're still talking just a few hundred calories. And what, 5 or 10% of your total daily energy expenditure, right?
Juna So so far we have two components. We have basal metabolic rate, which is the amount of calories you need just to stay alive. We have the thermic effect of food, which is the calories you need to digest the food that you've eaten. And there is one more category which is activity thermogenesis.
Eddie And you know, knowing you, you're not going to want to lay there in bed much longer.
Juna Yeah.
Eddie And after I fed you, you got like, all right, you know, enough of this. Do we have enough? I got to go, I got to go. I got to move. And you're going to want to go where? Maybe to the gym.
Juna Yeah.
Eddie And you're going to lift some weights.
Juna Then I'll have to clean my room.
Eddie And you have to clean your room, and. But let's stick to the exercise. You're going to get yourself to the gym, lift some weights, pull yourself on to the treadmill or the elliptical. And how many calories are you realistically going to burn up in your exercise activity? Thermogenesis.
Juna You know, the the saddest part of all metabolism research is that exercise is the tiniest portion of your metabolism. So when they look at studies, on average exercise is first of all, 0% of your metabolism because the majority of people don't exercise. But even for people who.
Eddie Don't move, it's if.
Juna You don't if you yeah, you don't do purposeful exercise. If you do do purposeful exercise, it's about 5 to 10% of your metabolism. And that makes sense because if you think about it, a lot of your exercise time is like getting to the venue of exercising. So like you have to get yourself to the gym, you go to the locker room, you're like fixing your hair, you're putting on your clothes, whatever. And then I don't know, let's say you burn a couple hundred calories during your exercise averaged out over the whole week. It's still not that many calories because we are burning so many calories doing all the other things to other week.
Eddie And I love that the acronym here is eat.
Juna Yeah.
Eddie So so when you read the articles and it says eat, you go, okay. Oh that's not about eating. It's about exercise activity thermogenesis. And to break that down I call myself out on a jargon alert. Thermo is again the heat. Genesis is you're creating the heat. You're creating the energy.
Juna Right.
Eddie So that's it. But I just want to share with the listeners that you and I have chosen to stand for this episode. And whilst keeping my mouth exactly the same distance from the microphone as best I can, I am sort of like twitching around here and, you know, just doing a little, a little dance as well. And we are doing non exercise activity thermogenesis. Ooh which is really neat isn't it.
Juna Yeah I was going to say that. I was just going to say it's neat. So we have a whole episode on this which I will link to in our show notes on non exercise activity Thermogenesis. But long story short, all you need to know is that it's the calories you burn with all the other non exercise movements in your day. So going to the grocery store, walking around, walking your dog.
Eddie standing to to a a podcast.
Juna Episode, typing at your desk. All of these things are your non exercise activity thermogenesis. And this is one of the most variable components of metabolism. People. So depending on how your lifestyle is laid out, your need can vary by thousands of calories. So, for example, somebody whose job is a very, very active I always think of my snowboard instructor, Ryan, because he's out in the cold all day. So it like takes him way more energy to keep himself warm. And he's like literally snowboarding all day from when he wakes up to like, you know, nighttime. And he has to eat so much because he's just on his feet all day long. And then I think of myself sitting at my desk all day, and then I come to the studio and I'm like, Eddie, I'm going to sit today. And I'm like, you know, what the heck? And then, oh my God, you know the worst part of all? What's okay? So I go to the dog park every evening for like an hour and a half to take my dog and have him play with all the other puppies. And I used to, like, stand outside with him, and I was like, oh, this is good for me. But then I saw other people. The dog park would bring folding chairs, so I bought myself a folding chair. I bought a pink one, and like, I loved it. But then I was like, honestly, like, I really shouldn't have bought this because I sit all day and I come to the dog park to sit again.
Eddie This is so ironic. So the people are sitting watching their dogs exercise. This is like the picture of the guy, like walking his dog with his hand out. He's driving his truck and the dog is on the end of a leash on this free walking assist as he's driving along. All right. So so if you want to if you're in Cambridge and you see someone sitting in a pink chair where they're very.
Juna Small, very.
Eddie Cute dog.
Juna With me, just yell, you know, shout out. I met a listener when I was walking to very recently and she said, oh my God, do you host food? And I was like, I do, and I was walking through there. So anyway.
Eddie Well, at least you're walking her. You are.
Juna Yes. You are standing there. Yes, I was walking, I was.
Eddie So the other thing about neat, which is neat, is that it's not just sort of the planned energy that we're talking about. Like, do you choose to walk around the soccer field while you're while your kid is playing or actually play with your dog, as opposed to watching them play with the other dogs? But even people sort of fidgeting and people that, you know, habitually don't like to sit. There is a correlation with weight. Yes. And so the easy correlation that's reported is that people who have obesity often don't move that much. And then you say, well, maybe it's hard to move when you're when you weigh more. Well, it turns out when they lose weight, a lot of these people habitually still don't move as much. And then you have someone who's slimmer, who is just kind of like always like moving. And you know, these people and you may be one of them and you may hear me sort of fidgeting here.
Juna And actually, my sister is like this. She is always fidgeting, okay.
Eddie So she's always moving. And then those folks, even if they gain weight, are still fidgeting.
Juna Yeah.
Eddie So there's something about what do we know? Do we know that it's actually.
Juna It's a gene for sure. There's something in the brain and there's different. So there's a lot of different components to this that we don't necessarily have control over. But basically there are just certain genes that will make you more or less likely to have the natural inclination to be moving. And that could be one of the reasons that explains why certain people in the same environment have trouble maintaining their weight and other people don't. Right. We'll talk a little bit more about that in our bonus episode on genetics. But for now, I know Eddie has a really good analogy to kind of bring together all these components of metabolism that we've talked about so far.
Eddie All right. Dollars and cents.
Juna Okay.
Eddie Basal metabolic rate, BMR. It's like basic expenses. I got to pay the rent in order to stay here next month. I got to keep the lights. I got to eat. You're not going out. You're not on holiday. You're not vacationing? Nope. No plane flights. Just kind of like. Back to you, Anna. Lying in bed for the experiment. Yeah. Okay. When you bring in the money while there's. You know, I always hate this. Like someone wants to pay you, and then they start subtracting all of these things like.
Juna Taxes, fees.
Eddie And that is your TEF or your thermic effect of food. But think of that as transaction fees, right? It's kind of, you know, just the tax on even eating or on bringing money in or sometimes and spending it. The activity thermogenesis is the fun stuff, right?
Juna Extras.
Eddie So now you say like, but I do want to go to the movie and I do want to get on that flight. Why is Eddie telling me not to book the flight? And I do want to go out for dinner, and that's activity thermogenesis. And I guess we could continue further to say some of it is a big activity that is like intentional, like, you know, going on a vacation, maybe that does that fit? Maybe.
Juna Yeah. Yeah. Okay.
Eddie So as opposed to I'm just going for a walk and I have money in my pocket and here I am in for coffee and you know, I'm now I'm thirsty. And did you see that guy with the ice cream like. And you could figure out how far away the ice cream is by how much it is in his cone. And you and you work your way over and like, oh, I didn't think I wanted ice cream, but I really do. And maybe that's just the, the non. Size activity thermogenesis. So that's my financial analogy.
Juna Okay okay. So now we're going to have a little bit of physics in this episode. If you can believe in.
Eddie Chemistry biology I.
Juna Know.
Eddie Physics.
Juna I know. So to understand the relationship that our metabolism has with weight loss and weight gain, we have to understand the first law of thermodynamics. There's the word thermal again, because it's about heat or energy. And the law is that energy cannot be created or destroyed, only transformed. When I saw this, I said, what does this have to do with anything? Right? I'm like, what are we talking about? Like I don't care. And the answer is, you guys, if you are going to be eating food and you're eating, let's say, 3000 calories worth of food because you see the calories on the package, right? And you're wondering, what does this have to do? Like I burn calories doing stuff in the day, but I'm eating these calories of food. And how do these two things interact? And the answer is, those 3000 calories of food don't just disappear when you eat them. They get transformed, and they're either transformed into the energy that you're using for your day. So you're ATP, or they're transformed into fat that you're storing away if there is too many. Right. So when you are taking in food, there is always a transformation being happened to turn that food into either energy being used or into fat stores. So very similar to your finance analogy, right? If you are taking in as much money as you spend, then your bank account just stays even and your fat stores are staying the same, right?
Eddie And probably my weight would stay the same then.
Juna Yes.
Eddie Got it.
Juna Our fat stores. I just want everybody to know. Like even if you think of yourself as quote unquote thin, like we all have fat on our bodies and we need to have fat and our bodies.
Eddie We have normal stores of fat which are part of our metabolism. For instance, a healthy woman will often have at least 20% body fat. Right? And that's if you think about it, I'm still stuck on the money thing. It's nice to have a balance. So you're not losing money, gaining money, but you also want to have a little money in savings, right?
Juna Right, right. And so if you take in as many calories as you are expanding in your total daily energy expenditure, your fat stores stay the same. If you start taking in more money than you are spending, you get to save more. AKA you put it in your savings account, aka your fat stores, right? So you build up some more fat stores.
Eddie So the money side sounds good. You have a bigger savings account, but on our bodies it shows up as fat under the skin or around our organs or in our butts or wherever. Your.
Juna Yeah, if only we could choose where it went. Awesome. But I'm just kidding this. And then the flip side is if you are all of a sudden expanding a lot more calories, like, I feel like now I'm doing jujitsu, which is taking up so many more calories than the gym did, because it's just so exhausting and I feel like I have so much less time to cook. And so now I feel like I'm spending more calories than I am taking in. And so then you will start to tap into your fat stores. So there's constantly this exchange happening and the calories you're eating are not disappearing and the calories you're burning are not disappearing. Everything is constantly being transformed into the form it needs to be for your body. Wow. So cool right?
Eddie It really is. And as we go on here, we're trying to make this simple and excuse me digestible, but but it actually gets a little bit more complicated. So here's like a little riddle for you. Ready. Yeah. You are in energy balance right. So we've just defined your number of calories you're bringing in is what you're burning for the day. You're not gaining weight. You're not losing weight. You're fat. Stores which are normal stay about the same. And everything is exactly the same. Okay. Yeah. And let's say you read an article about, oh, I'm going to take 10,000 steps a day, which is about five miles of walking. The average person who is actually based on a 70 kilogram white male.
Juna Perfect, which I.
Eddie Used to.
Juna Be in.
Eddie School.
Juna Where are you? Literally the average white male.
Eddie If you look, if you look it up, you'll see my picture here. That's your 70 kilogram white male was the average for labs and everything. So. Right. That person, if they walk a mile, burns about 100 calories, which is actually remarkably efficient, which also goes back to why we could, pursue animals.
Juna Right.
Eddie Long distances and not exhaust ourselves and be able to kind of outlast them. All right. So 100 calories, we're going to walk 10,000 steps. That turns into five miles. I can do the math with you. It's going to take me 500 calories. Yeah, that I wasn't otherwise burning. Okay. If I do that seven days a week, I'm going to do the math. 3500. Calories. That is the energy and a pound of fat.
Juna Right?
Eddie So I should, in the first week burn up a pound of fat. Right. And I should be able to continue, okay, week after week.
Juna 52 pounds a year.
Eddie And then 52 weeks later, you asked me to get back on the scale.
Juna And I'm like, I don't even. Where is he? I can't even see him. He's disappeared. He's gone.
Eddie And in fact, I have not lost 52 pounds. Oh, I've lost maybe five. I mean, so, like, okay, you and I, here's your riddle. What happened to all that energy?
Juna That is what we're going to talk about right after this short break.
Eddie And we're back. This has been a brief break for units. Try to figure out why I did lose 52 pounds just by walking an extra five miles per day.
Juna Oh my God.
Eddie You know, where did that energy go? And if we went all the way to Tanzania, might that help us figure this out?
Juna So, Eddie, actually, this experiment has been done to answer this exact question. So back in the day, you guys, let's let's think back 20 years in the yonder year of 2005, let's say. People thought in the early 2000, okay, the biggest difference between us and the way our traditional ancestors lived is that we don't move as much, right? So let's go look at some traditional hunter gatherer civilizations that are still around, still living the way that they used to thousands of years ago. And let's study them and let's see how much they move and how many calories they burn. And so they went to study a tribe in Tanzania called the Hadza tribe. This was Herman Pontzer and we actually had him on the show years ago. I think like in 2022.
Eddie We can still link to it.
Juna Yeah I know, yeah. We'll link link to it in our show notes. And we went to go see the that move about 20,000 steps a day on average.
Eddie So that's like ten miles at least. Right. Okay.
Juna They're watching on time.
Eddie Much more than we do.
Juna Much more. And so they go to measure how many calories they're burning every day because you think, wow, these people must be burning. Like, I don't know, 4000 calories a day, right? And the shocking finding was that the average Hadza male is burning the same amount of calories as the average Westerner, and the average has. A female was burning the average amount of calories as the average Western woman.
Eddie And just to paint the picture a little bit, these lab rats from the US go over there and do like doubly labeled isotope water experiments to determine exactly how much. And then they fly their samples back to the US and get this. And what do they say to each other?
Juna They're like, this is a mistake. We did something wrong. And they go.
Eddie Back. You just get just get another grant and you go back.
Juna And they measured it with like heart rate straps or something. And they came back again. They were like, this can't be right. And basically the conclusion they came to was that when you start moving a lot, your body compensates by reducing the amount of energy it needs for other things. So it basically becomes more efficient at the other tasks it needs to do, so that you have enough energy to move as much as you need to. And this makes sense because in the past, if there was periods where you needed to move around a lot to hunt or let's say you had less food, it would not be really useful for your body to just lose a ton of weight all the time, right? So your body is very resistant to losing large amounts of weight, which is why it has developed this adaptation mechanism.
Eddie All right. So I'm still a little frustrated that all I've lost is 5 pounds, even though I'm walking fricking five miles a day that I hadn't been doing before. Yeah, we'll talk about there's a lot of benefits to that. But if we're just talking weight loss, I have not lost all that. And part of it is that like my immune system now is not so energy hungry. It's a lot more efficient, right? I might not be as inflamed as I used to be, which is good for your health, right? And you're going to spend less calories there. And our bodies just amazingly adapt. So I've asked, well, we've asked on the air and I've asked lots of experts. So is a calorie a calorie? And the answer is yeah.
Juna But yeah.
Eddie It depends. You know what sort of state you're in.
Juna Yeah. Well, the cool thing is like, your body is meant to adapt, like it's doing what it's supposed to do. And the biggest discovery about metabolism over the past decade or so has been that it's not additive. So, for example, you experienced this yourself, right? When you run a marathon. You are burning so many more calories when you start training for a marathon. But do you lose that much weight.
Eddie I get so hungry. Yeah that. How could that.
Juna Happen. Right. Your body compensates with other things so it makes you hungrier. And you also get better at running. And you're running will burn less calories. Like your average mile at the same pace is going to take you less calories at the end of your training than it did at the beginning of your training.
Eddie So you become more efficient as well.
Juna Right. So when they do studies on people exercising while they're dieting and the first six weeks of the study, usually the person will burn about as many calories as you would expect them to burn from their exercise. But as time goes on, if you extrapolate months into the future, they lose only about a third of the way you would expect them to lose from the exercise.
Eddie So I just want to like, shout out that we're talking about how exercise is not a great way to lose weight, but and we have covered this, many, many times, and we will continue to do so. There are myriad benefits to exercise, so please keep on doing it. So if you choose to lift weights, you will put on trained muscle mass which is energy hungry. It will burn more. Calories, and that is one of the hacks to increasing your basal metabolic rate and therefore your total daily energy expenditure, and therefore possibly either losing weight or maintaining weight loss.
Juna Right. Which I do want to talk about the end of this episode. We need to talk about some of the hacks for either speeding up or maintaining a healthy metabolism. But before we get to that, I want to talk about one more thing, which is a study on the Biggest Loser contestants.
Eddie So from Tanzania, Africa to reality TV, take us away, you know?
Juna Okay, so this is, I think, one of the most interesting studies that I have ever read about because I personally grew up watching The Biggest Loser and being like, it's my dream. Not that I was. I was never like, the weight that the people on The Biggest Loser were. But I just had, you know, I thought it'd be so cool to, like, go to a boot camp and come back three months later just being like, oh, yeah, I look totally different. Like, I just loved the idea of being super drastic for three months, looking how you wanted to look and never having to deal with it again.
Eddie So I love the idea that this is reality TV. And yet Kevin Hall and others were studying the biggest losers, and to them, the 14 contestants were 14 subjects in the study. Right? And what did they lose? Like 128 pounds.
Juna 128 pounds on average on the show and their metabolism at the end of the show was about 610 calories less. So this makes sense because they're smaller of weight, right?
Eddie They're smaller. And anyone who's trying to lose weight, if you go from, let's say 200 pounds to 180, you're down 10%. You're always going to need less calories.
Juna Forever, right? That's one thing people never talk about. People like, I want to lose weight. I want his weight. I'm like, do you want to eat less for the rest of your life? Hello? But yes, that's always going to be a consequence. All right.
Eddie So they're down 610 calories in their total daily energy expenditure or their, quote metabolism. Right. All right.
Juna What okay.
Eddie What's wrong with that.
Juna So the study did a six year follow up. So everybody just went about their you know right. It's like a sequel.
Eddie It's a sequel.
Juna Exactly. They should do that. Oh my god. Well make them look really bad which is why they don't do it. But that would be such a good show. So six years later, the 14 contestants had regained on average, 90 pounds, right? So most of the weight had been regained. And you would think that their metabolisms would have gone back up because they gained the weight, right?
Eddie Yeah.
Juna Instead, what they found was their metabolisms were 704 calories slower from when they first met.
Eddie So they're slower than they were at the initial weight loss. And it stays lower.
Juna Yes, it got even lower. Even though they regained 90 pounds. Their metabolisms got even slower after six years. So on average, the contestants had lost some weight from the beginning of the show. But Kevin Hall and his colleagues calculated that the metabolic adaptation, which is the extra slowing of the metabolism that you would not expect from the weight loss, was about 500 calories, so their metabolisms were 500 calories slower than what you would have expected. So the way I always experience people, because it gets very confusing is imagine you had a 200 pound person. That had just always been 200 pounds. And then imagine a person that had been, I don't know, 300 pounds and had lost 100 pounds of weight. Yeah. That person who had lost a bunch of weight, their metabolism is slower than the person who had always been 200 pounds often. And the reason for this, we think, is because of the restriction that they had to go through for the extreme weight loss.
Eddie So their body was adapting to the restriction, right?
Juna Their body adapted so severely to the restriction, it had gotten so much more efficient and all its other tasks that now its metabolism was basically slower because that got gotten better at all these other things. And so this is why they always say, when, you know, people are giving you advice about weight loss, and they say it should be slow and steady. This is one of the main reasons why is because your metabolism does adapt to drastic lowering of food or drastic increases in exercise. Your body tries to protect itself against that by becoming more efficient at other tasks.
Eddie Also, if you go slow and steady, that'll give you a chance to hit the gym. Yeah, so lift the weights.
Juna Yeah.
Eddie To get more lean muscle mass or to at least mitigate its loss. Because when you lose weight, especially if it's going to be fast, everyone's hoping that it's going to be all fat, but you will actually lose the lean or muscle mass, right? And then if you regain, unless you're hitting the gym extra hard, right regain is going to be primarily fat, right?
Juna This always happens. So they've noticed this a lot with the new weight loss medications. People are losing so much muscle mass because they're losing weight so.
Eddie Fast because they're not eating as much as they used to. And they're okay.
Juna Probably also not. Exercising. Right. So okay, to end on a positive note, let's talk about some of the things that we can do to protect and or increase our metabolism. So the first step is going to be not to damage the metabolism. Right.
Eddie So your metabolism is not broken.
Juna It's not broken.
Eddie It's just adapting.
Juna Right?
Eddie You might be frustrated by that, but that's what it's doing. It's your job. Okay. So what kind of hacks or what kind of things can we do to support our metabolism?
Juna So first of all, avoiding yo yo dieting, avoiding extreme diets, avoiding extreme periods of overactivity. Right. Obviously, for some of us, that ship has sailed, right. I think probably for I don't want to say for most people, but for a lot of people, that ship has sailed like you probably have done a lot of yo yo dieting, especially if you're interested in this podcast and I'm right there with you. So that's totally okay. So let's talk about some of the things that can support an increase in your metabolism.
Eddie I think I've mentioned this a couple of times. Let's maintain and build your muscle mass.
Juna Yes. So muscle mass is one of the most expensive tissues the body has. It requires a lot of calories. And so if you can maintain your muscle mass and or increase it by lifting weights, which.
Eddie You can do at any age, you can lift weights at any age, but you can actually increase your muscle mass even at 100 years old. We never lose that capacity.
Juna Right?
Eddie And I'm going to add, I think we should just make this whole thing neat and easy. Any age. Just incorporate some more movement into your day, right? If you've got a podcast, do it standing.
Juna Yes. So incorporating more movement and building your muscle mass are going to be the two main ways of increasing your metabolism. And then of course avoiding extreme diets and like giving your body the nutrition it actually needs is going to be a way to support a healthy metabolism. So what are your biggest takeaways from this episode?
Eddie I think we need to celebrate our bodies. Yeah. And actually like understand. Well, this adaptation has kept us alive as a species. It is keeping us alive. Now let's support it, not try to overwhelm it with, as you're saying, like yo yo dieting, etc..
Juna Eddie, I love that and I'm so excited to talk about whether or not our metabolisms slow as we age and what impact genes have on your metabolism, which we will do on our bonus episode. So stay tuned for that. But until then, thank you guys so much for listening to today's episode. If you want to get an email where we break down a lot of the information in today's episode, you can go to food we need to talk.com/email. You can get the bonus episode in our show notes or go to food. We need to talk.com/membership. You can find us on Instagram at food. We need to talk. You can find me on Instagram at the official uni and uni on YouTube and TikTok. And you can find Eddie adapting.
Eddie And honoring that process.
Juna I love that Food We Need to Talk is produced by me and Rebecca Seidel and is distributed by Pyrex.
Eddie Our mix engineer is Rebecca Seidel.
Juna We were co-created by Kerry Goldberg, George Hicks, Eddie Phillips, and me.
Eddie For any personal health questions, please consult your health provider to find out more. Go to food. We need to talk.com. Thanks for listening.
