Sports Science Dudes
The Sports Science Dudes cover all the cool topics on sports science, nutrition, and fitness!
Email: SportsScienceDudes@gmail.com or Exphys@aol.com
Hosted by Dr Jose Antonio
BIO: Jose Antonio PhD earned his doctorate and completed a postdoctoral research fellowship at the University of Texas Southwestern Medical Center. He is a Co-founder and CEO of the ISSN (www.issn.net), and Co-founder of the Society for Sports Neuroscience (www.neurosports.net). He is a Professor of Exercise and Sport Science at Nova Southeastern University. Twitter: @JoseAntonioPhD Instagram: supphd and the_issn
Co-hosts include Tony Ricci EdD FISSN and Cassie Evans MS RD CISSN
Sports Science Dudes
Episode 77 Dr. Sofia Cienfuegos - Exploring the Impact of Intermittent Fasting on Health and Longevity
Can fasting unlock the secret to a healthier, longer life? Join us for a captivating episode with Dr. Sofia Cienfuegos, a clinical assistant professor at the University of Illinois at Chicago, as she shares her remarkable research on intermittent fasting and time-restricted eating. With origins in Chile and now thriving in the harsh Chicago winters, Dr. Cienfuegos offers a unique perspective on the science and practicalities of fasting. We explore the nuances between intermittent fasting and time-restricted eating, plus her groundbreaking study comparing four-hour and six-hour feeding windows.
University of Illinois at Chicago. Dr. Cienfuegos has a Ph.D. in human nutrition and has been studying intermittent fasting for the last seven years. Dr. Cienfuegos is an emerging expert in this field, with more than 30 publications in the most prestigious journals, such as Cell, Annual Reviews, and Nature. She has participated in several national and international scientific conferences and trained other professionals worldwide. Dr. Cienfuegos is the Co-I on two R01s (R01DK119783 and R01DK128180), examining the health benefits of fasting.
About the Show
We cover all things related to sports science, nutrition, and performance. The Sports Science Dudes represent the opinions of the hosts and guests and are not the official opinions of the International Society of Sports Nutrition (ISSN), the Society for Sports Neuroscience, or Nova Southeastern University. The advice provided on this show should not be construed as medical advice and is purely an educational forum.
Hosted by Jose Antonio PhD
Dr. Antonio is the co-founder and CEO of the International Society of Sports Nutrition and the co-founder of the Society for Sports Neuroscience; Dr. Antonio has over 120 peer-reviewed publications, and 16 books, and is a Professor at Nova Southeastern University, Davie, Florida in the Department of Health and Human Performance.
Twitter: @JoseAntonioPhD
Instagram: the_issn and supphd
Co-host Anthony Ricci EdD
Welcome to the Sports Science Dudes. I'm your host, Dr Jose Antonio, with my co-host, Dr Tony Ricci. You can find us find our podcast on Spotify, YouTube, Apple Podcasts, so make sure, when you're on YouTube, hit the like button like our show. Our special guest today is Dr Cienfuegos. She's a clinical assistant professor. I think you're still assistant. Are you associate yet?
Speaker 2:Not yet.
Speaker 1:Not yet, okay, well, eventually you will be In. You're still a sister. Are you associate? Yet Not yet, not yet, okay. Well, eventually you will be In. Kinesiology and nutrition at University of Illinois at Chicago, dr Cienfuegos has a PhD in human nutrition and has been studying intermittent fasting for the last seven years. She's an emerging expert in the field, with more than 30 pubs in the most prestigious journals. It's quite impressive. Here You're published in Cell Annual Reviews and Nature. That's pretty badass. You've also participated in several national and international scientific conferences and trained other professionals worldwide. You currently are a co-investigator on two R01s examining the health benefits of Examining the Health Benefits of Fasting. So first of all, sophia, welcome to the show.
Speaker 2:Thank you, I'm excited to be here.
Speaker 1:Did some research into where you're from. You're from Chile.
Speaker 2:I'm from Chile. Yes, South America.
Speaker 1:Which is one of those countries. And as a young kid I was kind of a nerd. I would look at a globe and I would be like, hmm, I want to go here, I want to go there. And when I saw Chile I'm like, wow, this is a really long country. And I didn't realize how long it was till I looked it up today. It is long. It goes from the bottom of California all the way to the Northwest territories of Canada. I'm thinking that's crazy. So it's like, oh, it's a thin country, no, it's a long country. So so it's like, oh, it's a thin country, no, it's a long country. So this has nothing to do with science, but I'm curious If you go from the northernmost tip of Chile to the southernmost tip, I assume the northernmost tip is tropical and the southernmost tip is cold. No, no.
Speaker 2:So actually the north part of Chile is usually it's like a desert, it's like that, so it's super dry, very hot, very dry like not non-tropical at all oh wow, desert.
Speaker 2:There's like a lot of minings and um. And then the south is patagonia. So I don't know if you heard of Patagonia logo. Yes, the south is very cold, but it's also really beautiful mountains, forests, it's gorgeous. I honestly am biased and I really like the south. The north, I mean, it's beautiful as well, but the south is, if you ever go to Chile, go to the south, it's so so the cold winters in chicago you're used to I'm from santiago.
Speaker 2:I'm from the middle and in the middle. In santiago our weather is exactly the same as in california. We have many, so it's like kind of like we have a little bit more seasons in california, but it's very mild, it's like.
Speaker 1:So the chicago winters are definitely rough for me yes, chicago is rough for everybody, I would tell you that.
Speaker 2:So uh, it's rough but I love it. I honestly love it here.
Speaker 1:I'm happy now you've been there not quite a decade, right at the university chicago eight years, now eight years yeah, and you going to stay there, get tenure and just who knows.
Speaker 2:Who knows After the pandemic? You know you cannot plan that much. You never know what's going to happen. You know it's like your plans can be. I don't know what's going to happen, but yeah.
Speaker 1:Well, well, first of all, thanks for being on the show, and I think what prompted me to want you to get you on the show is obviously intermittent fasting is a hot topic, particularly and we and Tony and I come from. We come from an exercise performance athlete background and so I I I tend to view IF from that lens versus looking at health and body comp or whatnot. But still, all of that's important. But when you gave a online seminar for us way back when and this is sort of jumping the gun to get to some details, but we'll get to some of the generalities later you published a really elegant study comparing four hour and six hour time restricted feeding.
Speaker 1:Now, before I go further with some of the specific data, on social media people use different terminology for what can be best described as you're not eating. Okay, so we have intermittent fasting, we have time-restricted feeding, and even within the IF world, some people have different definitions for intermittent fasting. You know, if you skip breakfast, that's intermittent fasting, if you skip dinner, it's intermittent fasting. So is there an accepted global definition for it? And if not, that's fine too, as long as we know what we're talking about. And compare IF to time-restricted feeding, because I know you use time-restricted feeding in that study.
Speaker 2:Yeah, so yeah, that's a really good question. We don't have a very universal consensus yet. However, what everybody doing research in intermittent fasting agrees on is that intermittent fasting is sort of like an umbrella term for the different types of strategies that would be considered intermittent fasting, so you have time-restricted feeding, like you said. We usually now call it time-restricted eating because feeding was called when we were moving from animal studies to human studies, and then in human studies we usually call it now it's time-restricted eating, because you feed the animal but humans eat. So that's why now it's time-restricted eating Okay.
Speaker 2:Yeah, so time-restrict restricted eating is the most common one, the one that people kind of associate with intermittent fasting the most, uh, where you shorten the amount of hours that you eat each day. So that could be either skipping breakfast or skipping dinner, however you prefer, but you eat on less hours than you usually eat. So you eat on an eight hour window or a six hour window, or a 10 hour window, you choose, and that's the type of vitamin fasting that we've been studying. But there are some other types of vitamin fasting. Another one is called alternate day fasting, where you alternate one day of eating normal and one day of fasting. The other day you eat normal, the other day you fast, and that fast could be a complete fast, so like zero calories, or it could be like a very low calorie diet, like 500 or 600 calories.
Speaker 2:There's another one that's called the 5-2 diet, where it's very similar, but you fast for two days a week. Those could be like consecutive or non-consecutive days, and then the remaining five days you eat normal. And then the last one is the fasting mimicking diet. I don't know if you've heard of the fasting mimicking diet. It's kind of getting popular. It's, uh uh, the main researcher in fasting, mimicking diets, dr walter longo, and it's basically a diet that you eat, but you eat very low calories, very low protein and it's basically like a plant-based uh diet that mimics what happens during fasting. So it's it's actually very low protein and it's. I don't know if you've seen prolon no, no those products where it's it's.
Speaker 2:So you do it five days a month, uh, and basically it's like as if your body would have been fasting for five days. I've never done it, but yeah, it's, it's getting it's. It's a little bit popular, I would say, but definitely the most popular one is time-restricted eating do you yourself, uh, engage in time-restricted eating um, I do do.
Speaker 2:There's some periods of my life where I do it more like strictly unconsciously, and some other periods but I would consider myself as someone that kind of naturally fasts. But that's not exactly the same as doing intermittent fasting, but still I I naturally kind of start eating later in the day. Uh, so for me, whenever I really want to like do intermittent fasting, it's not that difficult for me. But still I am someone that struggles. I struggle with eating enough protein. So for me, sometimes fasting is not the best strategy because it's a little bit difficult for me to eat enough you know it's interesting and, tony, we're a bit older than you, sophia.
Speaker 1:So we went through, we were part of the generation where it was hammered, and even in grade school. So, like we were told, breakfast is the most important meal of the day. Make sure you don't skip breakfast. And and, ironically, most people are just not hungry at breakfast. I mean, I'm not hungry, but I in a way, but in a way I avoid it by just working out and then I have a protein shake or something after I work out, but I'm not hungry in breakfast. But that point was always hammered home.
Speaker 1:And then I don't know when, data on fasting started to come out and then I was sitting there and I realized, wait a minute. So all these people who are skipping breakfast, they were basically intermittently fasting without calling it intermittently fasting. They just said I'm not hungry, so I'm not eating. And I always thought, well, what a great way to not gain weight. You're just basically skipping one of the meals out of. Most people eat three meals. So, tony, I don't know if you remember in grade school where it was like got to eat breakfast most important meal of the day.
Speaker 3:Yeah, absolutely yeah. We didn't want to leave the house without putting something in us, for sure yeah.
Speaker 1:So the question is, is it really the most important meal of the day?
Speaker 2:that's a really, really complicated question and there's been a lot of like debate about that lately in like the intermittent fasting world world. Um, because, okay, so it's. It's tricky because some people consider breakfast skipping as the same as intermittent fasting and not necessarily you could. You could be fasting and doing intermittent fasting and having breakfast as well, so maybe you have breakfast and you finish eating a little bit earlier.
Speaker 2:The thing with breakfast skipping is that usually breakfast one thing is like we don't really know what breakfast is. There's not like a universal definition of breakfast. So all the data on breakfast skipping, we're not really sure what people are considering breakfast. This is because of the time. If you eat it between 6 am 10 am, that would be breakfast or is it the types of foods that you're consuming there. So that's a little bit like I don't know, not very clear um.
Speaker 2:And also, breakfast skipping is, um related to many unhealthy habits. So usually breakfast skipper are people that go to bed really late and wake up really late as well, people that drink alcohol, people that smoke. So usually breakfast skipping is linked to other unhealthy things. So when you look at the population in general and you look at people that skip breakfast, they have worse health outcomes in general. Right, but we don't really know if it's because they're skipping breakfast or because of the many other variables are related to someone that is not having breakfast.
Speaker 2:People that have breakfast usually are from more stable houses, higher socioeconomic levels, more organized, healthier lifestyles, exercise, other things. So I wouldn't say that breakfast is the most important meal a day. However, it's definitely better if you're going to fast, if you're going to do intermittent fasting at least from my point of view it's better to do your eating window earlier in the day, so to have breakfast and have lunch and finish eating earlier, than to skip breakfast and like have lunch and dinner and doing your eating window kind of late in the day. Definitely doing it earlier is better. So I wouldn't say that there's one meal that's the most important one, but eating earlier in the day I would consider it better or healthier. I don't know if that made any sense. Hopefully it wasn't confusing.
Speaker 3:No, no, that made. That makes a lot of sense and I have actually done it the reverse way that you said, dr Sophia, which I finished. I went to an experiment for about six months when I lived in Texas where I finished eating about 430 every day and it was challenging. I'll say that I went to bed real hungry and I could not wait to get up, but it was definitely hit my lowest percentage of body fat. But I do have one question that follows on that one in terms of independent of whether we call it time-restricted eating, is there a minimum duration? We have to be without food in hours in order for it to qualify, so maybe just eight-hour regular fast, obviously from sleeping, is not enough. Do we know if there's a minimum window that would help qualify under any nomenclature, independent of what we call it?
Speaker 2:that's really good question, um and that. So studies have usually looked at the time for glycogen depletion to determine when like the fasting metabolism kind of starts. So the point where your glycogen stores are depleted and you have to start using fat, right, that's the point where you say, okay, the the fasting kind of metabolic state is starting to to take action, and that depends a lot on body size, right? So glycogen stores are mainly in the liver and the muscle. So, uh, I don't know, a hundred pound female probably in like eight or nine hours could start burning fat because their glycogen stores are probably already depleted. But I don't know, a 250 pound weight lifter male, probably those glycogen stores last for way longer because of the muscle and liver mass in general.
Speaker 2:But there is like in general people say that is around 12 hours. So usually the threshold is 12 hours. So if you're fasting for at least 12 hours or more, that would be considered intermittent fasting. If you're fasting for more than like 24 to 30 hours, that wouldn't technically be considered intermittent fasting, that would be considered prolonged fasting and actually the metabolic behavior of that is also kind of different. So it's anywhere between 12 and kind of 30 hours. That's the spot of for intermittent fasting.
Speaker 1:Could you comment real quickly on religious fasting or Ramadan fasting, how that is or is not different than sort of the traditional intermittent fast?
Speaker 2:Yeah, so actually many of the data that we had prior to starting doing research on intermittent fasting came from Ramadan fast studies studies. We know that it's safe, we know that people kind of lose weight, but but it's definitely different. So the two main differences, or three main differences, would be that, first of all, ramalan fast is done during the day, whereas time-restricted eating you fast during the night and you eat during the day. So ramalan you um start fasting when the sun rises and then you break your fast or you stop fasting whenever the sun sets. So during the day you're fasting and then at night, basically, you can start eating. So that's kind of the opposite. During intermittent fasting, you fast during the night and then around I don't know noon you start eating. You eat during the day and around seven or eight you stop eating and then. So it's like when you eat is kind of the opposite. Also, ramalan fast is a dry fast, so people don't consume any water.
Speaker 2:So that's also different from yeah, so there's during the fasting hours you're not allowed to drink water, whereas in intermittent fasting or time-restricted eating you are definitely allowed and encouraged to drink water. And also with Ramalan fast, whenever you break your fast at around well, depends on where you are, but around like 8 or 9 pm you usually break your fast with a feast that's called iftar, so it's like a like a real feast. So you get together with other families, you eat a lot of different foods and it's like a celebration. And that's also different from your regular intermittent fasting where you break your fast with just a regular meal that's not necessarily like a big feast, so they're different, um, but at the same time it's similar.
Speaker 2:So, in a way, that you're prolonging the amount of hours that you usually fast, and the results of ramalan fast are surprisingly good. Even though people are feasting and eating a lot, whenever they break their fast, they still lose weight. Some of their metabolic markers improve as well.
Speaker 1:So that's a lot of the data comes from those studies. Our data come from those. So they're still in a caloric deficit even though they're feasting.
Speaker 2:Exactly.
Speaker 3:And I would just interject that culturally, the foods they eat are probably significantly better than American foods. The foods they eat are probably significantly better than american foods. So yeah, if we would, if we were to do that here in this country, people be going mcdonald's at nine o'clock burger king. But culturally I think they, they, they really, you know, do well on their dietary practices too.
Speaker 2:So yeah, they kind of align with, like the mediterranean diet, which are definitely one of the healthiest ones.
Speaker 1:Yeah, in america it would be completely different right now, in terms of the uh, the benefits, the health benefits of intermittent fasting or fasting um, compare it to chronic caloric restriction, so with calories equated and also I don't know if it's you know data if protein is also equated, if the health benefits are related to just the loss of body weight, because you lose weight, and if you lose weight even from just exercise, all the metabolic markers improve. So is it just the fact that you're losing weight that confers the health benefits and it has nothing to do with the technique of intermittent fasting, chronic lark restriction, ramadan fasting, you know whatever. So what do you think?
Speaker 2:oh, that's, that's another really, really difficult question. Uh, that that's. That's actually the big question in fasting. Is it that fasting is just another strategy to make you lose weight and because of the weight loss you see all the benefits, or is it something else? It depends on who you ask. Honestly, uh, if you're asking me, I would say most 90 of the benefits of fasting is because of the weight loss. Yeah, so it's. It's another strategy to achieve a caloric restriction and negative energy balance.
Speaker 2:Weight loss there's been, and it's really difficult to study this because in order to try to assess if it's the weight loss or it's something else, you need to design sort of like a weight neutral study where people don't lose weight while they fast, and that's really challenging to achieve. There's been some tiny studies, short term with very few people, but very well controlled studies that I've tried to see, um see, like and measure this, and they've actually seen some improvements in the absence of weight loss. So, two groups uh, one of the groups fast, the other group is not fasting, it's doing a calorie restriction, but those two groups sort of not exactly a calorie restriction, but they're changing their diet, but they're maintaining their weight like weight neutral. They're not achieving any weight loss and the fasting group has improved some metabolic markers, decreased insulin markers, specifically related to insulin and glucoregulatory markers. But those are tiny studies uh, not a lot of people, so I wouldn't I wouldn't say too much about it.
Speaker 1:Well, I want you to speculate a little. If you were to guess, you have people fast but they're not losing weight, would it be better to shift those calories to the morning versus the night, and why? Or does it matter?
Speaker 2:You're asking me really difficult questions because it depends, in my opinion, in the perfect world, shift those calories to earlier in the day. So, like Tony said, when you eat earlier in the day and you stop eating earlier in the day, definitely you, at least from my point of view and from my opinion. Now it's better when you do it earlier in the day. Now, adherence is a big problem.
Speaker 2:It's difficult for people to do that it is really challenging, especially considering that most people have their family meals at nine. So the time where you can spend with your wife, your kids, it's usually at dinner. So telling people to skip that meal is really difficult. So if you tell them to eat really early, you might run the risk of them actually not doing it. So, in a perfect world earlier, in a real world, whatever they're able to adhere to honestly, yeah, whatever they're able to adhere to.
Speaker 1:Honestly, yeah, so assuming, tony, before you ask the question, assuming caloric deficit is the same, whether it's you know, I decide to eat less, smaller breakfast, smaller lunch, smaller dinner, or I decide to narrow the window of feeding, but the caloric restriction is the same, I assume weight loss is the same. Fat loss is the same, yes, no, maybe, so it's the same. And weight?
Speaker 2:loss is the same. Fat loss is the same. Yes, no, maybe. So it's the same and we've measured it. It's. It's the same.
Speaker 2:We we've, like the latest two or three trials that we've run has been comparing intermittent fasting with a calorie restriction. Uh, we've done using an eight hour window, so you eat during eight hours and you fast for 16 hours. The calorie restriction group restricts 25% of their energy needs and the results are basically the same. So you achieve the same results in terms of body weight and cardio metabolic like benefits If you're fasting for 16 hours versus if you're restricting 25 percent of your energy needs. Um, you can read that as like okay, fasting is useless. But you can also read that as passing is another stride, another tool to achieve a calorie restriction without having to make people measure what they eat.
Speaker 2:And there are some people that are really good at tracking calories. Right, probably the people that you guys work with athletes are really good at tracking macros and using apps and measuring. But the population that I work with it's usually people with metabolic diseases, prediabetes, diabetes are really bad at that. So if you can offer people a strategy where they don't have to measure, they don't have to track, they just have to look at watch and eat on less hours and basically they can eat whatever they want to eat. That's usually how we do it in our studies. They achieve the same results, that's at least, least from my perspective, it's really interesting and amazing.
Speaker 2:Now, that's with an eight-hour window. If you shorten the eating window even further, the results could be better. We haven't tested that, but they could be better.
Speaker 1:Tony, did you have a question?
Speaker 3:Yeah, it moves off the current order, so we're getting to the understanding that this practice is really good in weight management, weight control, perhaps decreasing body fat.
Speaker 3:There are a lot of Dr Sofia, a lot of other claims that are a bit extravagant too, that in terms of fasting and I don't want to go way out of bounds here, but I'm talking about all the various hormone releases or this hormone is mitigated If you fast. This hormone is increased, testosterone is increased If you fast. I mean from an evolutionary biology perspective, we would expect that the body had learned to adapt, probably at various times, to not having food for sustained periods of time. You know, we didn't have DoorDash and supermarkets so it wasn't as plentiful. But I guess one thing that is being for sure brought out to us hey, it's a great tool in weight management. But some of the other claims are there any things that are happening? Like I said, release of this hormone, the mitigation of that one, anything? I've even read things on why it's so much better for neuroplasticity and I don't know if any of that's true, but I don't want to go way off topic, but is any of it potentially even true?
Speaker 2:Yeah, so actually also a great question. So the problem with the research in fasting is that most of the research in fasting comes from studies done in animal models. Okay, and many of those results come from studies done in animal models, specifically mice. So the thing is, yes, yes, when you make mice fast for specific periods of time, you see some really amazing results. Uh, have we been able to replicate that in humans? No, uh, have we measured the exact same things in humans? No, and the length. So if you make a rat or a mice fast for eight hours, that's not the same as making a or 16 hours. It's not the same as making a human fast for 16 hours, because the mice or a rat will die of starvation at around like 48 hours or a little bit more. So it's as you you would, that you would fast for like weeks.
Speaker 2:So, the data is not really well translated from animals to humans and that's the biggest mistake that I usually see, like in social media and things that people take the claims from animal studies or even like cell culture studies and they like extrapolate them to humans directly, and that's actually a big mistake because those are things that we haven't seen in humans. Now there's every day we get more studies done in fasting, but most of those studies are really really tiny studies and some of those results like neuroplasticity or wow, we saw some decreases in IGF or we saw those are like tiny, sporadic studies and none of those results have been consistently seen in big, well done studies. So the only results that we've seen like consistently repeating in like bigger, longer term studies are benefits in weight, in insulin markers, some other cardiometabolic markers, some oxidative stress markers, but that's basically it. We haven't seen other like super interesting results replicated in big studies Not really.
Speaker 3:Maybe in a couple of years, but these might change.
Speaker 2:Maybe might change maybe, um, but yeah. So the only results that we've seen consistently happening are the ones that I just mentioned.
Speaker 3:Yeah, yeah and just cool. I mean that's a fantastic info. I didn't know that the the duration was only. I knew mice couldn't go too long, but 48 hours is not that long without food I'm not 100.
Speaker 1:Sure it's 48, but it's so, it's not yeah well, I want to add another sidebar discussion to this. Um, way back when, when I started looking at chronic caloric restriction data, just sort of for fun, because it's not my field, but, um, in many animal models or non-human models, if you calorically restrict, people live longer. So I want you to speculate on the chronic caloric restriction data in animals. Does it translate to humans? I imagine I don't know if there's human studies ongoing. I would imagine that's hard to do because what's? I mean, what's the clinical endpoint? Death. I mean we need to see how long people live and is living longer in those animal models.
Speaker 1:Partly because the environment is controlled. I mean I used to do a lot of animal work for my PhD and people don't realize how clean the areas where they house animals People think. People think, oh, it's dirty. I'm like it's cleaner than where people are because they have to keep it pristine. Animals cost a lot. You want them healthy. So I've I've never thought chronic caloric restriction improved longevity outside of the fact that you weigh less. But I could be wrong, it's just my guess. This isn't my field, but just as someone who reads this stuff, it's like that's kind of interesting. If I eat less I'll live longer, but maybe I'll be miserable, you know. So I want to eat.
Speaker 2:But anyways, speculate a little bit on that and its effect on lifespan yeah, so so exactly from animal studies we've seen that a chronic calorie restriction, or even fasting chronically, increases lifespan. Like you said, the environments, tightly, highly controlled environments of animals. It's impossible to replicate that in humans. Impossible.
Speaker 2:All of our studies are in pre-living conditions and again, it's really difficult to design a study to see if people live longer. It has to be like a really long cohort study. Observation like a different methodology, but actually uh, like observational data coming from like probably you guys have heard of the blue zones yes okinawas, uh, all of these areas in the world where most the highest density of like centenarians are.
Speaker 2:One of the things that they all have in common is that they live on a slight calorie restriction, and I think that's pretty significant, like if you study those populations where you see people that live past 100, 110 years old and you measure their diets and you know that they're consistently eating a little bit less.
Speaker 2:It's not a significant calorie restriction but, it's only 15%, 20% less calories than they usually, than they than they require. They live longer. We don't know if it's exactly that or the many other things that centenarians do, but I think it could be related. So there's many hypotheses behind that. Is it because you're weighing less? Less food, less oxidative stress, less mitochondrial stress, less other things? Honestly, I don't know what it could be, but I do believe that living on a slight calorie deficit can prolong lifespan. Why, I don't know that yet, but probably in a few years we might.
Speaker 1:Well, let me ask you sort of a oh, I'm sorry, tony.
Speaker 3:Well, just one quick thing. But that deficit is also in, I believe, in most of those areas facilitated by being physically active, if not exercising. So I think in concert, those two working together, probably really help, if I'm right there.
Speaker 2:Yeah, exactly. So they're all physically active, they're all living on places where there's like altitude, so they have to walk uphill every day, three times a day. So there's again. There's many other conf. They have to work right, walk uphill every day, three times a day. So there's again. There's many other confounders that could be right. We don't know which one it might be, but yeah, but yeah, they're on a slight calorie deficit.
Speaker 1:It could be because now, this is a fun conversation. I know tony and I our focus really is uh, you know, we get people who exercise, train and they want to be either stronger, they want to be faster, have more endurance, more endurance, have better body comp. So we really don't touch on hey, do you want to live longer? Because if you ask an athlete if they want to live longer, they're like what's I got to do? I just want to win. So this this is more of a speculative question to see where Sophia is. If your goal let's say your goal is you want to live as long as possible, okay, that's your goal. That is your goal. Yeah, what would you do, diet wise and activity wise, if your goal is just to live as long as possible?
Speaker 2:I know tony says he needs to lose weight, as do I yeah yeah, we're too heavy no, I would say that if I wanted to live the longest I could, oh uh, so people might disagree with me, um, but I definitely think that eating, of course, a healthy diet fruits, vegetables, hopefully not a lot of animals.
Speaker 1:I don't know if you might agree with me here or not um because, you'll be in a slight caloric deficit, sounds like a slight calorie deficit.
Speaker 2:Uh, you still have to watch your, your, your protein um, lots of fruits and vegetables, because you need those antioxidants mainly, and vitamins and minerals. And in terms of physical activity, of course, I'm not an expert on physical activity, but I do believe that people who are extremely, extremely active, like endurance athletes, like long distance runners, try out I feel like those types of sports too oxidative. So I would say, like resistance train, make sure that you have enough muscle mass, be active, but not severely active, because severely severely active I think it could be doing the opposite and it's gonna probably make you live a little bit less than more. So I think think it needs to be like in a fine balance. But I would say that mainly, preserving your muscle mass, doing resistance training, making sure your bone density is okay, are key to like longevity. So that would be my take. This is not my area of research.
Speaker 3:It's a good take. I'm agreeing with it wholeheartedly. I think high intensity training from an athletic performance standpoint is is not going to be beneficial at all. I mean volitional activity first. I think it's very important that if you're being physically active, you somewhat enjoy that activity, not just pushing through it because you have to torture yourself to excel. And volitional activity in my studies too, in animal studies, seems to be best. But yeah, everybody I know, I know it's anecdotal my family wants to die at 90 and lives to 100, but nobody ever worked out. All they did was everything exactly what you're saying, sophia Nice diet. They probably ate a little more animal protein than you do, but always active, lots of fruits and vegetables, no fake food, and probably walked at least an hour to two hours per day.
Speaker 2:For me, that's perfect.
Speaker 3:I believe that is myself. That's perfect.
Speaker 2:What do you think?
Speaker 1:Oh, I think I would agree with the slight caloric deficit just to keep body weight down. It's interesting you mentioned when you do extreme volumes of cardiovascular exercise. I know people who have had issues with their heart. I mean your heart is a muscle. You have had to have multiple surgeries, atrial ablation. There's an MD PhD out of Canada who he himself said you know what Doing these long, long, long distance races, it may not be good for your heart.
Speaker 1:I mean, it's humans. I mean, evolutionarily, humans aren't meant to run at a very high capacity for long periods of time. They're really when people like well, prehistorically you had to hunt, I'm like, but they trotted, humans didn't run fast, they would trot and eventually the animal they were chasing would get tired. Because humans have a great aerobic capacity, second only to dogs and horses, although some people, people say no, humans are better than horses, I'm like, eh, I think dogs number one, horses number two, humans number three. So I agree with that, the resistance training part, maintaining bone mineral density, et cetera, et cetera.
Speaker 1:But what's interesting is people who do live long. They don't do hardcore exercise, they're just, they just move. Yeah, they just move, you know it's so. When, when, when Tony squatting. It's like, tony, that's not helping you live longer. When I do paddling races, I'm like I know this isn't isn't helping me live longer, but I like doing it, so you know, it's sort of sort of who I am and Tony. Tony's one of the few people at our age who can still do sprints, so that's something, I think, that will happen.
Speaker 3:But it makes me happy and I honestly believe that if you're enjoying that activity, the effects are completely different than forced physical strain, right?
Speaker 2:Exactly. I completely agree with that.
Speaker 1:Okay, we're running out of time, but there's one very specific question and one general question. I wanted to ask the general question is this any potential drawbacks to intermittent fasting? But I want to get to the specific question first and it has to do with you published a really elegant study it was in cell metabolism, the title of it, so people could look it up Effects of four and six hour time restricted feeding on weight and cardiometabolic health or randomized controlled trial in adults with obesity. And what caught my eye and actually you had mentioned this in a webinar that you gave I'll be exact. It's on figure four, looking at body composition, and you're comparing four-hour TRF, six-hour TRF and the control. And the six-hour time-restrict restricted feeding or fasting lost lean mass compared to the four hour and the control. So what say you?
Speaker 2:oh, it's definitely a tough one, so. So something that I usually say about fasting is that if you're not mindful of your protein intake just like with any other kind of restrictive pattern you run the risk of losing a little bit more lean mass. Just like with calorie restriction if you don't watch the amount of protein that you're consuming, you can lose lean mass. Now, we would have expected in that case to see more lean mass loss in the more restricted group. That's the four hour, but actually we saw that in the six hour. So we thought about it, possible ideas. We looked at their food records. Maybe they were eating less proteins, maybe no, nothing was significantly different. So we're not completely sure why that happened. It could have been a measurement error, it could have been dexas, even though dexas are really good for measuring body composition. We run into a very big problem with dexas, and that is that dexas are not well fitted for people with obesity um the box. So so do you work with?
Speaker 1:uh, yeah, we we have, we've done, but we dexa athletes so we don't really deal with obese population.
Speaker 2:So if you think of the dexa box? Uh, an athlete fits, yeah, but if you think of someone with a bmi of 38, it's more difficult.
Speaker 2:So there's usually parts of their bodies that we cannot measure very well. So we have our strategies to try to do it, like replicate the positioning, pre and post trial, all of that, but there's also there might be a little bit of error in there, so it could be that. So we we honestly don't have a clear explanation, and that's something that that it's kind of frustrating for us. In terms of the dexas, we wish there were dexas that were bigger, that we can, that we can use for measuring people with with larger body sizes, but, um, I think I don't know. I don't know if you have any other hypotheses or theories about it.
Speaker 1:No, I don't because Because I remember when you went over it, I'm like wow, I can't explain this. I actually have to know and I think the most reasonable one is just measurement error, because you're dealing with bodies that the DEX is good but, like you said, there are limitations to it.
Speaker 2:Limitations, I forget and MRIs, and yeah, there's yeah because it wouldn't indicate anything that's behaviorally different.
Speaker 3:It wouldn't indicate anything in activity or, as you mentioned earlier, having more discipline, or I'm trying to go to a lot of different places and at least at the moment I can't figure anything out, but it's complex. Yeah, yeah, it's quite fascinating. Anyway, I mean again still, the good news is an effective method for weight loss.
Speaker 2:That's all that really matters at the point, right yeah it is, and I always say watch your protein and make sure that you're resistance training or any type of training, because, again, if you don't watch your protein and you don't do any physical activity, you definitely run the risk of losing muscle mass.
Speaker 1:Yes, yeah, makes sense, makes sense, okay. One final question drawbacks, um of intermittent fasting. What are the pros and cons? And also, is there, is there? Is there a difference in the psychology of it, meaning people who do caloric restriction, chronic caloric restriction, versus I think I'll do if instead, is there? Is there something going on there?
Speaker 2:um, so we haven't measured that exactly, but usually what we say is that people that cannot restrict calories every day, that don't have the discipline or that don't want to change what they eat, they don't want to, like, select specific eat, they don't want to select specific foods. Intermittent fasting is a really easy and interesting strategy for them. Drawbacks, so, like I said, potential loses in muscle mass. Actually, in terms of hormones reproductive hormones what we've seen is that testosterone tends to decrease more than increasing.
Speaker 1:Male and female.
Speaker 2:Male and female. In males, the studies that have seen decreases in testosterone is not a very clinically significant decrease in testosterone and also no significant effects on like like endurance and strength and other markers are also related to testosterone. Nothing, so it's. I wouldn't say it's clinically significant. However, for females it is clinically significant but it's actually something that's more positive because among females there's some specific diseases that are caused because of an excess testosterone and actually the trial that we're running now it's among females with PCOS. So polycystic ovary syndrome. That's a specific condition where females have excess testosterone and fasting can be specifically helpful on that condition.
Speaker 2:But for males that are specifically trying to increase muscle mass, I wouldn't say that fasting is the best strategy. Honestly, I would say there are other strategies. If you're trying to decrease your body weight in general, if you're trying to cut, fasting could be a good strategy. But for bulking or gaining muscle mass, fasting is not the best strategy, at least from my point of view. There are some risks on specific life stages or pregnancy, breastfeeding. We're not really sure. We don't have any data, so we usually advise against it. People with a history of eating disorders we usually also advise against it. So I think that would be the main drawbacks of intermittent fasting. I think I'm missing something from your question, is there? No, that was it. Uh.
Speaker 1:Drawbacks the other one was, um, the psychological effects. I mean, if there are, if there is anything specific to intermittent fasting, uh, psychologically, but I think you had mentioned it it's just it's just easier for some people to restrict calories that way versus oh my God, I got to eat less at breakfast, lunch and dinner. This will be horrid.
Speaker 2:Yeah, and it's something psychological though. That's interesting about fasting is that usually whenever people start fasting like consciously fasting like, for instance, the study that we're running now I just met with a couple of my participants that they have to start eating at one and they stop eating at seven, so they're doing a six hour window. So this is the study. For females with pcos, the first week is awful. They hated the first week because you are changing your normal eating schedule and your body always reacts, always. So the first week is like awful and people usually feel tired and grumpy and but it's really interesting that in almost all of our studies what we've seen is that those are able to stay to it the first week. The second week is way easier and the third week they don't even remember that they're fasting. They like get used to it, like immediately, like the body readjusts to the new like eating schedule really, really well.
Speaker 1:So is this with or without exercise?
Speaker 2:uh, so no, we're not making them exercise anything, in particular because we're isolating the effect of fasting. But we do give them like Fitbits, so we track their activity to see at the end if there were any significant differences. But we're not making them exercise in this study.
Speaker 1:Well, this has been a fun conversation, Sophia. Tony, do you have any final words?
Speaker 3:I'm just really glad we had it because I've learned a lot. Really, it's fantastic, sophia. Tony, do you have any final words? I'm just really glad we had it because I've learned a lot. Really, it's fantastic, sophia. It's great to get some real clear answers from a great scientist that dedicates her life to this, as opposed to just scrolling around and hearing all kinds of crazy information. But really informative and thank you, because I love walking away learning, and I certainly did. This was great.
Speaker 1:Where can people find? If you're giving a talk at a conference, typically, where would you go? People are more interested in what you do.
Speaker 2:So I have an Instagram account, but the problem is a lot of that is in Spanish, but but yeah, so it could be my Instagram account. I'm also on Twitter, but very little, and I'm also on YouTube. So, yeah, probably there, you guys can email me your. Instagram is your name, or my name in Instagram is S-O-F-I-A Sofia, s-o-f-i-a Sofia, s-o-f-i-a 100. Because my last name is Cienfuegos and Cien is I got it.
Speaker 3:Yeah, I found you. Wow, look at this 120,000 folks following. That's a big deal.
Speaker 2:Honestly, I'm not that active anymore because I'm too busy, but during the pandemic, when all of our studies studies were shut, I became active on social media and now I'm like yeah, there seems.
Speaker 1:There seems to be a relationship between how active you are as a scientist and how inactive you are on Instagram, because there there are some scientists. I'm like how do you get all these followers? Oh, that's right, you're not doing any studies so when I wasn't doing any studies, that's when I got all the followers all right. Well, hey, thank you so much, sophia, for being in the sports science dudes. Hopefully we'll get this thing posted tomorrow, but we learned a hell of a lot and uh, keep up the great work.
Speaker 2:Uh, you know it's super interesting stuff and again, thank you so much yeah, thank you very much for inviting me, and if you have any questions, anything, please reach out. I'll be happy to like continue discussing or answering any questions that you have. So thank you so much. This was super fun All right, thanks.