#1 Neuroscientist: "Even A Little Bit Of Alcohol, Caffeine & Sugar Does This To You!" Dr Tommy Wood

Dr. Rangan Chatterjee 0:00 There's a lot of confusion out there around health. One minute we hear something's great for us, the next week we hear something's bad for us, and I don't think it needs to be as complicated as it sometimes might appear to be. So my hope today is that we can help people cut through the confusion.

Dr. Tommy Wood 0:16 Sounds fantastic.

Dr. Rangan Chatterjee 0:17 Yeah?

Dr. Tommy Wood 0:17 Yeah.

Dr. Rangan Chatterjee 0:18 Alcohol.

Dr. Tommy Wood 0:19 [laughs] Go.

Dr. Rangan Chatterjee 0:21 I, I thought we'd start with alcohol.

Dr. Tommy Wood 0:22 [laughs]

Dr. Rangan Chatterjee 0:22 Okay, is there any benefit for our health when we drink alcohol?

Dr. Tommy Wood 0:28 No. Um, but as with everything, and I imagine most of the topics we'll talk about today, there are always caveats. So if you look at hard health outcomes, there's some mixed, uh, results and mixed research, and what previously we thought was that moderate alcohol consumption, so within, say, the alcohol guidelines, um, was associated with, with better health outcomes overall. So not drinking alcohol is less good for your health than, than drinking some. Um, when you then sort of break out the diff- the different health conditions, um, you might see that s- a small amount of alcohol intake or regular alcohol intake is associated with lower risk of cardiovascular disease, but then that's balanced by a slightly higher risk of certain cancers. So overall, if your main outcome is, say, how long do you live, there doesn't really seem to be any, any effect, uh, o- of alcohol, uh, either, either beneficial or, or, or negative in terms of moderate consumption. If you try and then figure out, well, what's a s- a safe amount to consume, uh, there are several studies, and you know me, I'm particularly interested in the brain. So there was a, a recent study that looked at brain volume, so the size of people's brains, which is... which decreases over time, that's associated with risk of cognitive decline and dementia. And a drink once a week seemed to be just fine, but beyond that, you maybe start to see some, some detrimental effects.

Dr. Rangan Chatterjee 2:03 Are you saying there, Tommy, that our brain volume will decrease over time as we get older, but that more than one drink a week, potentially one alcoholic drink a week, increases that?

Dr. Tommy Wood 2:16 So when you look at these kinds of data, they're generally not longitudinal, as in they don't look at the same person over time. What they do is they look at people across ages and across levels of drinking, and at one snapshot in time, they say, "How much do you drink and what does your brain look like?"

Dr. Rangan Chatterjee 2:36 Oh, so it's not the same person they're tracking.

Dr. Tommy Wood 2:37 It's not the same person. So we kind of... So we cannot say that, um, alcohol is the driver here. Uh, when you do this kind of epidemiological research, we call it an association, right? This amount of alcohol is associated with these changes in the brain, but we don't know if it's truly causal. Um, we can adjust for a whole-- But that's what we do with statistics, we adjust for other things that may be accounting for that, and then we, we think whatever's left is a signal. So, so I think that there are a few studies that basically suggest that drinking one or two drinks one or two times a week is probably fine, but anything above that, there's certainly no benefit, and then it may be detrimental to our brain health and our, our, our other health. The other side of that, though, is that, um, often people drink alcohol in social situations, and that if it's helping to facilitate social connection, and it means, you know, you're going down the pub with your mates so you get to spend time and, and, and talk with them, that probably offsets some of tho- some of those effects. So it's not always black and white, good or bad. Um, but higher levels of drinking than that, uh, don't seem to be associated with improved health and may be associated with wor- worse health. Um, but there... You know, drinking some amount is probably just fine. Uh, but then context and other things are gonna be important as well.

Dr. Rangan Chatterjee 3:54 Yeah, I think you've bring up some really interesting points, and it's kind of one of the reasons I wanted to have this conversation with you, is to try and bring that context, a nuance that I think is often lost in the conversation around health these days. You know, everything's either good or bad.

Dr. Tommy Wood 4:12 Yeah.

Dr. Rangan Chatterjee 4:12 Which diet is best? You know, is alcohol all good or all bad? It's like, well, hold on a minute. It kind of depends. And I agree that it's pretty hard to make a case that there's a physiological benefit to consuming alcohol. But I think we also have to acknowledge that many cultures have managed to drink small amounts of alcohol now and again-

Dr. Tommy Wood 4:36 Yeah

Dr. Rangan Chatterjee 4:36 ... in community.

Dr. Tommy Wood 4:36 Absolutely.

Dr. Rangan Chatterjee 4:37 And they seem to have high rates of longevity-

Dr. Tommy Wood 4:39 Yeah

Dr. Rangan Chatterjee 4:39 ... and minimal disease. So it's like everything, it's balanced, right? And you can look at the blue zones, for example, which are front and center of everyone's mind at the moment because of, you know, the Netflix show. And I know there can be some debates on various things in the blue zones.

Dr. Tommy Wood 4:52 [laughs]

Dr. Rangan Chatterjee 4:52 But I think one thing we can say is that many of these populations, they do drink alcohol, but they're also doing a lot of other things very well that may counterbalance that, like low stress, nutritious foods, strong sense of community, and all these things. So yeah. I- if we say, though, what are the negatives, if we, if we really try and address, okay, for someone who does drink, let's say, more than that one drink a week-

Dr. Tommy Wood 5:20 Mm-hmm

Dr. Rangan Chatterjee 5:21 ... and goes, "Well, I feel okay," right? "You know, I think I'm eating well, I'm moving my body well," um, you know, but you're saying more than one drink a week may be problematic. How would you have them think about that? You know, are there some key things, for example, you'd say, "Well, just watch out for these three things because this is what alcohol consumption can do-"

Dr. Tommy Wood 5:42 Mm-hmm

Dr. Rangan Chatterjee 5:42 ... "if you're not careful"?

Dr. Tommy Wood 5:44 It's really difficult to tease that out at those very moderate levels, you know, within, say, government alcohol guidelines, right? Because it's gonna be very subtle, and you may not... there may not even be something that you can, you know, put your finger on and say, "That's definitely something that you n- you need to watch out for." Um, when you talk about the blue zones, they may... You know, some of them, they may drink red wine every day. But in general, portion sizes are much smaller than we would consider a, a-

Dr. Rangan Chatterjee 6:16 Mm-hmm

Dr. Tommy Wood 6:16 ... glass of wine, say, uh, i- in the UK. Um, so it's probably even more moderate than, than we might think, and of course all the other things that you mentioned, uh, come into play. So one, one thing that I see very frequently is people really don't want to give up alcohol.

Dr. Rangan Chatterjee 6:35 [laughs]

Dr. Tommy Wood 6:35 And, and I, and I, I, I'm not here sitting saying that you should. Of course, you know, I, I, I do dri- I do drink, uh, uh, occasionally and socially. But you might think about, you know, what is it that's alcohol is, is facilitating for you? Like, why has it become a habit, if it is a habit?

Dr. Rangan Chatterjee 6:53 Mm.

Dr. Tommy Wood 6:53 And so if it's the socio- social aspect, then actually now it's much easier to get non-alcoholic cocktails, non-alcoholic beers. You can still go out, and you can have that, that same kind of ritual with your friends or, or with yourself that gives you that feeling of relaxation even though there's no alcohol involved. So you can get all of those benefits. You can still feel like you're getting that de-stressing at the end of the day with-

Dr. Rangan Chatterjee 7:17 Mm

Dr. Tommy Wood 7:17 ... like a beer in front of the TV or something like that. Um, all of that is still, is still possible. Um, and so you can think about maybe re- replacing those things in, um, occasionally. And then it's also worth thinking about often when people sort of fight against the idea that may- maybe they may be drinking too much, often we, we hear about... that it's like they're bargaining. "Oh, but I do all these other things, so isn't it okay that I drink alcohol?" And I'm not here to, to-

Dr. Rangan Chatterjee 7:43 Yeah

Dr. Tommy Wood 7:43 ... judge one way or the other, but it's just worth thinking about. Like, are you trying to find ways to justify it? Um, and if you are, then that maybe signifies that there's worth thinking about even deeper and, and, and maybe considering some alternatives.

Dr. Rangan Chatterjee 7:58 Yeah, I really like that approach. One thing I think about with my patients who are in this conundrum is I, I always talk to them about their sleep.

Dr. Tommy Wood 8:06 Mm.

Dr. Rangan Chatterjee 8:07 Because I think alcohol for many people disrupts their sleep, and often they're not aware of it.

Dr. Tommy Wood 8:14 Yeah.

Dr. Rangan Chatterjee 8:14 You know, if they get this sleep fragmentation, they're waking up multiple times in the night, they don't always know that. They just know they feel tired-

Dr. Tommy Wood 8:21 Mm

Dr. Rangan Chatterjee 8:21 ... the next day. And I've found that some people don't always put that together-

Dr. Tommy Wood 8:24 Yeah

Dr. Rangan Chatterjee 8:24 ... with alcohol the night before. So I know with certain patients, I've said, "Why don't we try a week without, just see how you feel?" And sometimes they'll go, "Wow, I've got so much energy, and I'm sleeping better."

Dr. Tommy Wood 8:35 Yeah.

Dr. Rangan Chatterjee 8:35 And then that's empowerment 'cause I'm very much like you, Tommy. I don't really wanna tell people what to do with their lives. I don't think it's my place to. And I think alcohol now is becoming the, again, a big thing that we're talking about in the public health arena for good reason 'cause many people do have a problematic relationship with alcohol. But I think we've gotta be very careful it doesn't go to nobody should be drinking-

Dr. Tommy Wood 8:57 Yeah

Dr. Rangan Chatterjee 8:57 ... ever. I personally don't really drink much anymore. I don't think I've had an alcoholic drink in maybe four or five years now. I have no ethical or moral problem with people who do-

Dr. Tommy Wood 9:07 [laughs]

Dr. Rangan Chatterjee 9:07 ... at all. It's just in my own life, I've found I got to a point where I just don't need this anymore.

Dr. Tommy Wood 9:13 Yeah.

Dr. Rangan Chatterjee 9:13 Like, it's not doing anything for me, and I prefer the way I feel without it. So yeah, I don't know. Anything else you wanna add on alcohol perhaps?

Dr. Tommy Wood 9:22 Yep. From my own personal experience, I notice that it affect, negatively affects my sleep. That's one of the reasons why I don't drink very regularly, you know, maybe once a month or something. Because I certainly feel less well-rested the next day. It, it, um, affects your temperature regulation, so you're, like, like, hot during the night or other things. You just don't feel as, as, as, as rested. So that, that certainly, uh, it's a nice in because I- I think that's something that, that people will, will appreciate, that that's gonna be important, and they'll notice the difference.

Dr. Rangan Chatterjee 9:50 And may I ask, given that you know it affects you negatively, 'cause this is the funny thing about alcohol-

Dr. Tommy Wood 9:56 Mm

Dr. Rangan Chatterjee 9:56 ... I think. We, we all know, I know when I was drinking, that you're gonna not feel good the next day-

Dr. Tommy Wood 10:01 Yeah

Dr. Rangan Chatterjee 10:01 ... or you're not gonna be your best self the next day, yet we still do it.

Dr. Tommy Wood 10:04 Mm.

Dr. Rangan Chatterjee 10:05 So I guess it's a bit of a personal question, but given that you know all that, and I kind of... I'm asking this just for the purpose of asking it rather than, you know, trying to highlight anything because, you know, we're all human.

Dr. Tommy Wood 10:18 Mm.

Dr. Rangan Chatterjee 10:19 Given that you know it's gonna negatively affect your next day, what goes through your mind before you actually consume it?

Dr. Tommy Wood 10:26 So I've... historically, I- I've, I've struggled with a lot of these things around alcohol. I had what some people might have considered disordered eating a long time ago and being very hyper-focused about the quality of the food that I ate and, and, and what I ate, and so it's taken me a long time to work on some of those things. And in reality, I've g- gotten to a point where I'm... where if I've decided to do it, then I lean into enjoying it. So if I'm gonna eat this cake, I'm gonna enjoy this cake.

Dr. Rangan Chatterjee 10:57 Yeah.

Dr. Tommy Wood 10:58 Like, this is, you know, I'm... or all, and all the reasons why, why I'm eating it, just like if I'm gonna have a nice cocktail, I'm gonna make sure it's a, it's a nice cocktail. I'm really gonna enjoy it.

Dr. Rangan Chatterjee 11:06 Yeah.

Dr. Tommy Wood 11:06 I'm with my friends. I'm having a nice dinner. So I really lean into, um, the enjoyment factor because the, the alternative is spending hours then worrying about the thing that I ate or the thing that I drank and how that's gonna affect my health, and that worrying is probably worse than the-

Dr. Rangan Chatterjee 11:22 Yeah

Dr. Tommy Wood 11:22 ... eating and drinking itself. So I embrace the, the positive sides of it because, you know, it's usually a social aspect or so-

Dr. Rangan Chatterjee 11:29 Yeah

Dr. Tommy Wood 11:29 ... or some other thing. And then, uh, and I think that's, that's how I approach it.

Dr. Rangan Chatterjee 11:32 Yeah. Love it, Tommy. Thank you for sharing that. Okay.

Dr. Rangan Chatterjee 11:35 Let's move on to caffeine.

Dr. Tommy Wood 11:36 Uh-huh.

Dr. Rangan Chatterjee 11:36 Okay? There's plenty more I could do on alcohol-

Dr. Tommy Wood 11:38 [laughs]

Dr. Rangan Chatterjee 11:38 ... but I think I'm gonna try and discipline myself to keep moving through topics today. Caffeine, good or bad for our health?

Dr. Tommy Wood 11:47 Uh, yes. [laughs] Um, as, as ever, and I think this is gonna happen several times, the, the answer is, uh, it depends. Um, there's... Certainly, if we go back to the, uh, epidemiological observational evidence where you ask people how much coffee they drink and then you look at their health outcomes, it seems like drinking up to, you know- Three or four, maybe more small cups of coffee. So, so probably like one or two of my cups of coffee, um, per day is associated with, um, improved health outcomes, and that's, uh, liver disease, Alzheimer's disease. Um, and then, um, there's certainly no, no signal of harm, right? So it, it doesn't seem to be harmful up, up to those levels and, and, and maybe some benefit. Of course, there's no randomized controlled trials of coffee drinking that, that show that definitively. Um, but there does seem to be some potential benefit there, and there's, there's lots of, um, polyphenols and other things in, in, say, coffee, for instance, or, uh, or tea. Um-

Dr. Rangan Chatterjee 12:48 Could you just explain what a polyphenol is-

Dr. Tommy Wood 12:50 Yeah

Dr. Rangan Chatterjee 12:50 ... for someone who doesn't know?

Dr. Tommy Wood 12:51 Yeah. So these are the compounds, often they're colorful, that make up these beans or berries, and it's the same... They're in the same class of compounds that make, like, blueberries blue. But they have, um, uh, coffee has its own, um, compounds like that, that seem to affect our gut microbiome. Uh, they affect our vascular health, and there are randomized controlled trials actually on some of that. They extract those polyphenols out, and they give them to people and look at their cardiovascular function or their, you know, their, uh, the health of their blood vessels or their cognitive function, and they seem to be beneficial. So, um, those are the kinds of things that are coming along for the ride, uh, with caffeine. But sometimes, uh, when you look at the research, like decaf coffee, for instance, doesn't... It has some of the benefits, but maybe not all of the benefits of, of, uh, caffeinated coffee. But again, you have to think about, well, what kind of person drinks decaf versus regular coffee? And it's probably the differences in those people that's driving that, rather than the caffeine itself. So I think there's definitely a signal that some caffeinated beverages, uh, you know, may be associated with improved health outcomes, and that's probably 'cause some of the compounds that come along for the ride in those, both tea and coffee separately. But then you have to think about the other side. So what are the things that caffeine can potentially negatively affect? The most obvious one is, is sleep, and different people have different, uh, abilities to metabolize caffeine. So there's a gene, uh, that, that affects how fast you metabolize caffeine, and anybody who's done a genetic test will have probably gotten that on there-

Dr. Rangan Chatterjee 14:21 Yeah

Dr. Tommy Wood 14:21 ... and know if they're a fast or slow metabolizer. And there's some early evidence that suggests that people who are slow metabolizers that drink a bunch of caffeine may be getting some negative, uh, effects of that just 'cause it's hanging around in their system for, for much longer. Um, but you probably know that a little bit about yourself anyway, or a lot of people do. So I, you know, I know some people who are very sensitive to caffeine, right? They have any at all, and they're awake for 24 hours.

Dr. Rangan Chatterjee 14:45 Mm-hmm.

Dr. Tommy Wood 14:45 They can't sleep, whereas, um, others... And then, uh, again, it becomes, you know, you don't know what's habit versus real. But some people who say, you know, "I can drink caffeine late at night, and it doesn't affect my sleep at all," we don't really know if that's necessarily true. But it's certainly, there's, there's some good evidence from, uh, randomized controlled trials. There's a meta-analysis that came out, um, in the last year or two that, that looked at caffeine intake, and it can affect sleep architecture and how much sleep you're getting.

Dr. Rangan Chatterjee 15:11 Negatively.

Dr. Tommy Wood 15:12 Negatively, yes. So then it's just a case of making sure that you're timing your caffeine relative to your sleep so that it doesn't negatively affect your sleep. Um, so for me, I try not to drink caffeine after midday because there was this period of time where I was having coffee, you know, every night and, you know, we're in the lab or, and everybody's drinking coffee in the late afternoon. This is very... I did my, did my PhD in, uh, in Norway, and it's very normal to have a cup of coffee at 4:00 in the afternoon or something. I couldn't figure out why I couldn't sleep. Um, and then, then it, sort of tinkering with caffeine timing, that, that, that made a really big difference. But that's gonna be very personal from, from person to person, like how much, how much it affects them. The other thing that I think is very interesting about caffeine is how it affects cognitive function, and if you're doing very simple tasks or you're very sleep deprived, caffeine does seem to be beneficial. But if you consume a lot of caffeine, it can actually negatively affect your cognitive function, particularly on complex tasks. So it might improve your action time, but if you had to think through some complex task, and they, they do this in the lab with, like, complex executive function, like how, how, how fast can you interpret this diagram or how fast can you, uh, like reel off these different things? Having a bunch of caffeine in your system can actually make you perform worse, and it's interesting because people think they're performing better, but they're actually performing worse. So caffeine, like, improves your mood, which we know it does, but it doesn't necessarily improve your performance.

Dr. Rangan Chatterjee 16:45 Yeah. It's so interesting. There's quite a few things to pick up on there. First of all, genetic testing. I like the theory behind the genetic testing of fast metabolizers to slow metabolizers. But what I've seen with certain people and experienced myself, I think I am a fast metabolizer genetically.

Dr. Tommy Wood 17:07 Ah.

Dr. Rangan Chatterjee 17:07 But I'm exquisitely sensitive.

Dr. Tommy Wood 17:09 Yeah.

Dr. Rangan Chatterjee 17:09 So I'm like, wait a minute. The genes are saying this, but I can be... I've got to be very careful with my caffeine intake, both in terms of dose and timing. For many years, I won't touch caffeine after 12:00 midday-

Dr. Tommy Wood 17:22 Mm-hmm

Dr. Rangan Chatterjee 17:22 ... unless there's some, you know, I'm, I'm tired and I'm s- I'm driving, right?

Dr. Tommy Wood 17:28 Yeah.

Dr. Rangan Chatterjee 17:29 Or I really need to get through, knowing there may be a consequence that evening as well.

Dr. Tommy Wood 17:33 Uh-huh.

Dr. Rangan Chatterjee 17:33 But for, for whatever reason, I need to get through something. So that was the first thing to comment on, so-

Dr. Tommy Wood 17:38 And I would just quickly respond to that by saying that whenever you think about any part of a biological system, it's not just one thing that's important.

Dr. Rangan Chatterjee 17:47 Yeah, exactly.

Dr. Tommy Wood 17:47 Right? So, um, your caffeine metabolism will tell you how far, like, well, it should tell you on average how fast you'll clear it, but caffeine attaches to a receptor. It's an, it's a, it's an ad- adenosine receptor antagonist. So there's gonna be polymorphisms in the receptors. There's gonna be differences in, in how you then respond to that, to caffeine binding to that receptor and what happens in the cell, and that's gonna be different from person to person as well. So yeah, you're right. Just that one thing isn't gonna be enough to tell you exactly how you're gonna respond to caffeine.

Dr. Rangan Chatterjee 18:18 Yeah. And I think also something I'm quite passionate about, whether it be alcohol or caffeine, is that I've noticed with patients and myself that the kind of stress load in your life Also can play a role here. For example, I remember when I did use to drink, not to excess, but if I'd have a glass of red wine or a beer in midweek, let's say after work-

Dr. Tommy Wood 18:40 Mm-hmm

Dr. Rangan Chatterjee 18:40 ... sometimes I wouldn't sleep so well, and you'd feel it the next day. You know, maybe one or two units of alcohol. But the same amount when I was on holiday, I wouldn't feel a thing.

Dr. Tommy Wood 18:50 Yeah.

Dr. Rangan Chatterjee 18:51 Now, it could be, you know, different alcohol, but, you know, it was kind of similar, and I really thought about this. I thought, "Well, my stress load is right down. I feel I've got a lot of headroom psychologically and mentally as well." And I think, you know, I really think about this idea that I don't think we can completely separate biology and psychology. Like, I do feel there's something about us. If you're really, really stressed and you're using caffeine to get you through, I don't know. I, I, I really sort of believe there'll be a different impact-

Dr. Tommy Wood 19:21 Yeah

Dr. Rangan Chatterjee 19:21 ... if you're very relaxed and drinking it.

Dr. Tommy Wood 19:24 Yeah. And caffeine partly activates the sympathetic nervous system, which, you know, the stress fight or flight side of your nervous system. So if you're adding, if you're pouring that on top of a whole bunch of other psychological stress, of course, there's the potential for a greater negative effect. Like the context is, is important as well. Absolutely.

Dr. Rangan Chatterjee 19:43 Did you ever see the study, uh, I think it was in 2011 from the University of Bristol, where they looked at caffeine drinkers, and they tried to really answer the question from recollection, does caffeine really enhance performance-

Dr. Tommy Wood 19:57 Mm

Dr. Rangan Chatterjee 19:57 ... and ex- enhance our cognition? And the conclusion of that study was, if you are a habitual caffeine drinker, then yes, consuming your caffeine in the morning does raise your mood and cognition, but only to the level of where non-caffeinated drinkers-

Dr. Tommy Wood 20:15 Yeah

Dr. Rangan Chatterjee 20:16 ... are all the time. And I find that really interesting 'cause it kinda makes sense to me that for a lot of us, that would be the case that if we... 'Cause in the past, I have quit, and I haven't had it for a few months, and I'm like, "I feel great all the time."

Dr. Tommy Wood 20:28 [laughs]

Dr. Rangan Chatterjee 20:29 Even I don't need a morning cup of tea or coffee. But I do enjoy it. So what is your perspective on that, and then how does that fit alongside the fact that athletes, for example, or I know you work in Formula 1, for example, so I don't know if you encourage your drivers to maybe have caffeine or not.

Dr. Tommy Wood 20:49 So that's a, a very well-cited study, the one that you mentioned. I think that's probably right, is that a lot of that first caffeine boost is just making up the, the caffeine deficiency that you've, you've [laughs] generated because you're so habituated to it, and that takes you up to sort of like your normal baseline. Um, and then you can, you can wean yourself off within a couple of weeks, and that, that effect goes away. Um, the... I think the f- the Formula One drivers, it's very different from, from driver to driver, but something that I've noticed over the years actually fits very well with what I was saying earlier. So there are multiple components to performing well in that environment. But if you think about, uh, the beginning of a Formula 1 race, there are two things you want to do. You want to get off the line as fast as you can.

Dr. Rangan Chatterjee 21:36 Mm-hmm.

Dr. Tommy Wood 21:37 And you want to navigate the first corner while 19 other cars are trying to do the same thing. So caffeine, and this is based on the work of Yerkes and Dodson, uh, which looks at how, um, at your arousal level and your performance of, of tasks, and there's this, there's this classic arousal curve, which is basic- which basically says that the more aroused you are, the better you perform, up to a point where greater arousal is basically more anxiety and more stress, and then your performance goes down. And every sport has its own sweet spot-

Dr. Rangan Chatterjee 22:12 Mm-hmm

Dr. Tommy Wood 22:12 ... for arousal. So if you're a sprinter in the blocks, your ar- your optimal arousal level is very different from a snooker player, right? Or a, or an archer.

Dr. Rangan Chatterjee 22:22 Mm.

Dr. Tommy Wood 22:22 Even in the, even in the Olympics, right? The... So that's why, um, they banned beta blockers, which sort of calm down your nervous system in those sports where you wanna be, like, very calm, like, like archery, say, or, or some kind of shooting or snooker. Um, whereas-

Dr. Rangan Chatterjee 22:38 I think used to in the '80s-

Dr. Tommy Wood 22:39 Yeah

Dr. Rangan Chatterjee 22:39 ... I think even they'd drink whilst playing snooker. I think so.

Dr. Tommy Wood 22:42 Yeah, because it would calm them down. Exactly.

Dr. Rangan Chatterjee 22:43 Exactly.

Dr. Tommy Wood 22:43 Yeah. Um, for that reason. So they were adjusting their arousal curve. Um, but something like caffeine will im- improve your performance, um, in a simple cognitive task or a simple task. So particularly, what the thing that they measure, measure is reaction time. It's often called a psychomotor vigilance task. So if you wanna get fa- if you wanna get off the line fast in a Formula 1 car, caffeine is great.

Dr. Rangan Chatterjee 23:07 Mm-hmm.

Dr. Tommy Wood 23:08 Um, but what happens is that you can get to a point where your caffeine dose is so high, it will then affect your ability to navigate the first corner. Because all of a s- which is a much more complex cognitive task, because you're trying to figure out the direction you're going, plus where all the other cars are. Um, and so you can, you can caffeinate... You want to caffeinate yourself to the point, and not all drivers use caffeine. This is the, like some find some benefit from small doses at the right time. But you wanna improve your reaction time off the line, but you don't want to negatively affect your ability to then navigate the first few corners of the race. So there's a really fine line in terms of that arousal curve, and I've seen that in action in Formula 1 drivers, so it's, the thing is really interesting.

Dr. Rangan Chatterjee 23:49 Yeah, absolutely fascinating. Even that idea that different sports have got different times where you want to peak.

Dr. Tommy Wood 23:56 Yeah.

Dr. Rangan Chatterjee 23:57 And I guess then taking it back to a non-sportsman, well, we've all got different things in our lives that are important to us and different times in the day when we want to peak, right?

Dr. Tommy Wood 24:08 Yeah.

Dr. Rangan Chatterjee 24:08 So, you know, again, what's the right dose for you? What's the right time for it? Which I guess comes with experimentation.

Dr. Tommy Wood 24:14 Yeah.

Dr. Rangan Chatterjee 24:14 And just trying to bring alcohol and caffeine together and sort of close them off, I guess what you're saying, and I would agree with Tommy, is that there's pros and cons, and we need to figure out what works for us. And if, for example, you really enjoy ... your caffeine, and it has no seemingly negative effects on your mood, your anxiety levels, or your sleep. And even if you accept that drinking it might just bring you back up to the level that if you didn't drink it, but you get so much enjoyment out of it, you know, I love a good cup of black coffee in the morning-

Dr. Tommy Wood 24:51 Yeah

Dr. Rangan Chatterjee 24:51 ... for sure, then it's probably worth it.

Dr. Tommy Wood 24:54 Yeah.

Dr. Rangan Chatterjee 24:55 But if you enjoy it and love it, and it's giving you palpitations and anxiety, and it's trashing your sleep, and you're moody and reactive with the people around you, you know, you might wanna rethink about [laughs] your relationship with it, basically.

Dr. Tommy Wood 25:09 [laughs]

Dr. Rangan Chatterjee 25:09 So it's not black or white.

Dr. Tommy Wood 25:12 Uh, uh, when you sort of bring them together, I think if you think about, uh, our collective modern lifestyles, that's a phrase that you use, um, what, what often happens is that you'll drink at the end of the day, then you'll need to ... You won't sleep very well. You'll have to drink coffee all day because you're sleep deprived. And then to wind down, you're gonna need alcohol at the end of the night. So they, they often reinforce one another. And so, again, it's just worth thinking about how is it, uh, affecting you. Is, is there ... Is it possible that there's this, they're sort of perpetuating, perpetuating a cycle of one another that you can somehow try, try and break? And if it's not neg- negatively affecting you and you're still performing well, you feel good, great. You know, we ... Neither of us would recommend that you change anything. But it's, it's possible that they, they can go hand in hand in that way as well.

Dr. Rangan Chatterjee 26:00 Yeah. And the, the whole point of this conversation, Tommy, and I think for me you're the perfect person to have this conversation with, is there's too much of, in my view at least, is it good or bad?

Dr. Tommy Wood 26:12 Yeah.

Dr. Rangan Chatterjee 26:13 Uh, you know, you can't really answer that question. And hopefully, certainly for alcohol and caffeine, hopefully we've given people a few things to think about.

Dr. Tommy Wood 26:21 Yeah.

Dr. Rangan Chatterjee 26:21 What about sugar? Again, sugar is something that people say, "Well, is it good or bad?" And I know [laughs] it depends.

Dr. Tommy Wood 26:27 [laughs]

Dr. Rangan Chatterjee 26:27 And we're gonna hear that a lot today. But why don't you tackle sugar? Where, where do we go wrong with sugar? You know, is sugar intrinsically problematic for us, or is it more the volumes that we're consuming?

Dr. Tommy Wood 26:40 Of course, I, I think it's the, I think it's the latter. It's both the, the quantity and the context of it. And there's been a lot of interest in terms of, um, so basic sugar, sucrose, which is 50/50 glucose and fructose, is a disaccharide. It just means two sugars bound together. And fructose has really come under the microscope recently because it can affect our uric acid levels, which is-

Dr. Rangan Chatterjee 27:05 Mm

Dr. Tommy Wood 27:05 ... often used ... Well, it's, well, it's a risk factor for gout, but it's often used as like a sort of marker of our metabolic health. And fructose can affect cellular energy levels if it's, you know, in the way that it's metabolized, and it can be quite intensive on the cell, particularly in the liver.

Dr. Rangan Chatterjee 27:20 What, what does that mean, cellular energy levels?

Dr. Tommy Wood 27:22 Yeah. So inside the cell we have this energy currency called ATP. And, uh, in order to metabolize fructose, we end up using all of that within the cell. And you can get to this point where it's almost a stressor on the cell in order to metabolize it.

Dr. Rangan Chatterjee 27:39 Mm.

Dr. Tommy Wood 27:39 And that's maybe one of the reasons why, uh, fructose is an issue for some people. And it's certain ... you know, high amounts of fructose consumption and/or sugar, which is 50% fructose, can increase the risk of things like fatty liver, um, fatty liver disease, which is increasingly common. Although the other side of that is that there are potentially other nutritional deficiencies that are af- affecting the ri- your risk of that, um, uh, as well. Uh, particularly choline, uh, which, uh, is important for, for packaging, uh, fat, uh, out of the liver. And if you don't have enough of that, then the liver, the liver can accumulate fat with, with high amounts of, of sugar. But in reality, when I think about individual food components, and there are [laughs] several other things that we could talk about that are controversial in addition to sugar, but it's really the context of the sugar that we're currently consuming, and like you said, the quantities of it. I like to think that the majority of our diet should be minimally processed and nutrient dense foods, so they, you know, support the function of our bodies. And other than just being a source of energy, there's nothing else in sugar that's, that's really beneficial. So if you're consuming a large proportion of your calories from sugar, you're not consuming foods that have nutrients in that are then important for doing everything else.

Dr. Rangan Chatterjee 28:59 Mm.

Dr. Tommy Wood 28:59 And it's ... That's really the same with all ultra-processed foods or, um, highly processed, um, packaged foods. They're generally nutrient poor, calorie dense. They negatively affect our ability to understand our hunger and satiety signals, and we know that we overconsume them because they're hyper palatable. We eat much more of them than we would of something else that's less processed. And people get into the issue of what processing actually is or what processing means. And so, like, the definition of ultra-processed foods basically means that it's highly refined and they've usually added additives, fillers, and things like that in order to keep it shelf stable, so you can just, like, stick it in a packet and it can stay there for, for months or, or years on end.

Dr. Rangan Chatterjee 29:42 Years on end. [laughs]

Dr. Tommy Wood 29:43 Yeah. [laughs] Um, and so I don't particularly ever focus on sugar individually, uh, because it would be very easy to remove sugar, but you just replace it with some other highly processed food that, um, is, is, you know, is, is gonna have the same effects because it's outcompeting more, more nutritious foods. Um, so in general, I would think about an ... the entire dietary pattern because there's, there's no evidence that some sugar is detrimental to our health really.

Dr. Rangan Chatterjee 30:14 What do you mean by that? Because that ... Some people are gonna go, "What do you mean? Uh, wait a minute. I, I thought sugar was bad for me."

Dr. Tommy Wood 30:18 Yeah.

Dr. Rangan Chatterjee 30:18 So when you say there's no evidence that some sugar is detrimental, ju- just expand on that a little bit, Tommy.

Dr. Tommy Wood 30:25 Yeah. So, um, in general, if you are eating within your caloric requirements and you're otherwise healthy, then consuming some sugar doesn't really seem to have a negative effect, right? It's a source of energy. Um, there's no real reason to assume that, you know- A large part of our metabolism runs on glucose. Um, when we metabolize fructose, which is the other half of sugar, it gets turned into glucose. It gets used as an energy source. So if you're in otherwise good health and you're eating, you know, consuming enough of the nutrients in general from your diet, there's no reason why sugar should be detrimental. It's when it then becomes, uh, the major source of energy and you're not getting all these other things that we might need from our diets.

Dr. Rangan Chatterjee 31:14 Information is not enough to make change in your life. You have to take action. So to help you take action after watching this video, I've created a free Nutrition Guide for you. This contains the five most important practices I've seen in over two decades of seeing patients. They work for you no matter what your dietary preference. There's a step-by-step action plan to help you implement those changes in your life. If you wanna receive that free guide right now, just click on the link in the description box below.

Dr. Tommy Wood 31:45 So when ... Usually, when people cut out sugar, what they've done is they've dramatically improved the quality of their diet because they're eating other things now. Um, so I'm not, I'm not, uh, exonerating sugar in itself, but I think that focusing purely on that doesn't really tell us the, the greater story of what's the overall quality of your diet and what, what's the overall sort of balance of nutrients you're taking in, and fiber and, and, and o- and other things.

Dr. Rangan Chatterjee 32:14 A- and I think, again, it's that point of context and what else is going on in your life-

Dr. Tommy Wood 32:21 Mm

Dr. Rangan Chatterjee 32:21 ... kind of influences whether sugar's a problem for you or not.

Dr. Tommy Wood 32:25 Yeah.

Dr. Rangan Chatterjee 32:25 And it's interesting, you know Mark Sisson, the ... Would you call him a paleo guy or, you know-

Dr. Tommy Wood 32:31 He's pri- primal

Dr. Rangan Chatterjee 32:31 ... Primal.

Dr. Tommy Wood 32:32 Yeah.

Dr. Rangan Chatterjee 32:32 Primal, yes. And Mark, for people who don't know Mark, I think he's just gone 70 years old.

Dr. Tommy Wood 32:38 Yeah.

Dr. Rangan Chatterjee 32:38 He's in-

Dr. Tommy Wood 32:38 He's in fantastic shape

Dr. Rangan Chatterjee 32:39 ... fantastic shape.

Dr. Tommy Wood 32:40 Yeah.

Dr. Rangan Chatterjee 32:40 Eats a very primal, ancestral way of eating-

Dr. Tommy Wood 32:43 Yeah

Dr. Rangan Chatterjee 32:43 ... for a number of years. He's been talking about it, promoting it. But if he ever tweets about the fact that he will ... I think he enjoys sugar in his coffee each morning.

Dr. Tommy Wood 32:53 Uh-huh.

Dr. Rangan Chatterjee 32:53 Like one spoon of sugar. Oh my God, people go nuts on it.

Dr. Tommy Wood 32:57 [laughs]

Dr. Rangan Chatterjee 32:57 And I would imagine that that really speaks to exactly what you're saying, that 90% of his diet is really good.

Dr. Tommy Wood 33:03 Yeah.

Dr. Rangan Chatterjee 33:03 Whole foods, nutrient dense. He's fit and active. He moves his body every day. He looks after himself. In that context, one small spoon of sugar in a coffee each day is probably not a issue, right?

Dr. Tommy Wood 33:20 Yeah.

Dr. Rangan Chatterjee 33:20 In that context.

Dr. Tommy Wood 33:21 Yeah, absolutely.

Dr. Rangan Chatterjee 33:22 Someone else who, let's say, has a highly processed food diet, eating to excess, not 'cause they're, they're lazy or gluttonous, because they struggle. They-

Dr. Tommy Wood 33:31 Mm

Dr. Rangan Chatterjee 33:31 ... we all struggle, right? In that context, they may find that sugar or the amount of sugar in their diet is problematic. Is that, is that another way we can look at this?

Dr. Tommy Wood 33:39 Yeah. I, I think so, and, and some of it can also be ... You know, there's, there's a big debate in the scientific world as to whether sugar is addictive or not, and you'll have people who have some, uh, some evidence on both sides. And-

Dr. Rangan Chatterjee 33:54 Sounds like most things these days [laughs]

Dr. Tommy Wood 33:55 ... right, like most things. And I would say that I'm, I'm not really sure. Like in, in some people who consistently overeat, they do, you know, get a large activation of reward centers in the brain when they eat sweet things. Whether that's the same as addiction is very difficult to really parse out, although some people certainly have very problematic eating behaviors, and that's its own psychological disorder that requires specialist inter- intervention. But you're right that f- when we think about how, um, we respond to certain foods, uh, part, part of the problem in, in ... With the, with the processing is that ... And so when, when you're taking ref- refined sugar, um, you've extracted it from sugarcane or sugar beets. You've, you've taken it or, you know, we're ... As, as a species, we very regularly have consumed sugar either from honey or from fruit, right? And nobody would tell you that eating an apple is gonna be bad for you even though, you know, there's a, a few grams of sugar in there.

Dr. Rangan Chatterjee 34:55 Well, some people would these days, actually.

Dr. Tommy Wood 34:56 Well, I-

Dr. Rangan Chatterjee 34:57 [laughs] But generally.

Dr. Tommy Wood 34:58 Well, that, that I, that I think we can say is n-

Dr. Rangan Chatterjee 34:59 [laughs]

Dr. Tommy Wood 35:00 I'm confident saying that's not correct. Um, but when you, uh, process foods with industrial, modern methods, you divest the calories from their context. And so-

Dr. Rangan Chatterjee 35:16 Divest is a big word, Tommy.

Dr. Tommy Wood 35:17 Sorry.

Dr. Rangan Chatterjee 35:18 What's a, what's another word for that?

Dr. Tommy Wood 35:19 You, you, you, you separate, you separate them out.

Dr. Rangan Chatterjee 35:21 Yeah.

Dr. Tommy Wood 35:21 Right? They're ... So when ... So say we're ... Historically, evolutionarily, if you did eat some fruit, you eat some sugar, and that c- it comes in this context of-

Dr. Rangan Chatterjee 35:31 Yeah

Dr. Tommy Wood 35:31 ... water and fiber and all these other things, and there's ... The body expects some context for that sugar, um, in terms of ... And then how it affects your physiology and your hunger signals and stuff like that afterwards. When we process those foods and strip them out, the response that you get physiologically is no longer the same from the same amount of, of that food. So they've done this with, um, various grains, right? If you take a, a whole grain, you, you, you could cook and eat, uh, a handful of pearl barley, say. You know, it's minimally processed. That's how it looked on, on the stem.

Dr. Rangan Chatterjee 36:10 Mm.

Dr. Tommy Wood 36:10 It's still got all the fiber, all the context. Um, and then you look at how that affects your blood sugar. Um, it pro- it probably has a quite small effect on your blood sugar. If you then take that same thing and you cook it and you grind it, um, or you grind it and you cook it and you turn it into a paste, or you turn it into bread, it has a much bigger effect on your blood sugar. You ... It's exactly the same thing.

Dr. Rangan Chatterjee 36:29 Mm.

Dr. Tommy Wood 36:30 But what you've done is you've changed the context of the food, and then that affects how your body responds to it. So you're no longer getting macronutrients, um, like things like carbs and fats or protein in the context that our bodies are used to getting them.

Dr. Rangan Chatterjee 36:47 Mm.

Dr. Tommy Wood 36:47 And so that's where it starts to become problematic. So- When b- when you create processed foods, you might add sugar to something that doesn't normally have sugar in it.

Dr. Rangan Chatterjee 36:56 Mm.

Dr. Tommy Wood 36:57 And then that makes you wanna eat more of it because you've, you've started to create, and that's the idea of creating hyperpal- hyperpalatable foods.

Dr. Rangan Chatterjee 37:04 Yeah.

Dr. Tommy Wood 37:04 So even savory foods have some sugar in, 'cause you start to activate different receptors. You start to then drive a greater likelihood of, of overeating them. So that's where it starts to become problematic.

Dr. Rangan Chatterjee 37:14 So let's say the population we were looking at was all healthy. Everyone was of a, you know, a healthy weight, in inverted commas. They were metabolically healthy.

Dr. Tommy Wood 37:25 Mm.

Dr. Rangan Chatterjee 37:25 Then in that context, of course, which isn't the context we're living in today, certainly not in most countries around-

Dr. Tommy Wood 37:31 Yeah

Dr. Rangan Chatterjee 37:31 ... the world these days. I- I- if that was the situation, then sugar here or there in our tea or coffee or whatever, you know, a sweet treat if you want, and I'm not convinced I love the word treat, but-

Dr. Tommy Wood 37:43 [laughs]

Dr. Rangan Chatterjee 37:43 ... we, I think people know what, what we mean when we say that. You know, maybe once a week or once a fortnight or whatever, you know, or, or whatever you choose to do may be okay.

Dr. Tommy Wood 37:52 Yeah.

Dr. Rangan Chatterjee 37:54 How does that though sit in the context of what we have today? So we know in the US, for example, what is it now? Is it 90% of US adults may have some degree of metabolic dysfunction?

Dr. Tommy Wood 38:05 And actually, the UK and Europe and most of the world are catching up, so you can't, we can't even single out the US anymore.

Dr. Rangan Chatterjee 38:10 So if we're saying the bulk of the adult population, and it's not just adults, I know, but the bulk of the population, unfortunately these days have a degree of metabolic dysfunction, so the way they're processing energy in the body is not as efficient as it could be, and that's leading to an increased risk of all kinds of diseases. In that context, is sugar now becoming even more problematic?

Dr. Tommy Wood 38:38 It's absolutely contributing due to the way that we're, due to the way that we're using it. The, but again, I think it comes down to the entire context of the diet because you could certainly get to a point where, say we dramatically reduce sugar in foods. If that then comes with like a parallel decrease in overall caloric intake, say, there will absolutely be, be benefit. But when other people are in charge of creating these foods, you know, these ultra-processed foods, those sugar calories are just gonna be replaced by something else, and you're gonna j-

Dr. Rangan Chatterjee 39:14 Mm

Dr. Tommy Wood 39:14 ... you're, you're gonna overeat it just as much, and it's not really gonna d- gonna change anything. So I, I think that if by reducing your sugar intake, you decrease your overall caloric intake, and you improve your, um, the overall quality of your diet, that's absolutely gonna be beneficial. But if that doesn't happen, and this, this often happens with the way that we engineer foods nowadays, is just it'll be replaced by something else.

Dr. Rangan Chatterjee 39:40 Mm.

Dr. Tommy Wood 39:41 And it, and it, and it may not make the same difference. So I, I think it really depends on how that gets enacted. If, if people-- So if you say that I want to reduce my, you know, I'm gonna focus on sugar, and you focus on reducing sugar intake, and then with that comes, you know, you're not eating cakes or biscuits, and with that you've dramatically both decreased your, you know, overall energy intake and improved your diet quality. That's gonna come with im- uh, with health benefits. But it's if you then say, "Well, I'm not gonna have cake, but I'm gonna have, uh, you know, an extra serving of fries instead," right? There's no sugar in that, but I'm not convinced you, you're not gonna-

Dr. Rangan Chatterjee 40:20 Yeah

Dr. Tommy Wood 40:20 ... get any healthier. So it really depends on-

Dr. Rangan Chatterjee 40:21 Yeah

Dr. Tommy Wood 40:21 ... how those changes then, what the knock-on effect is.

Dr. Rangan Chatterjee 40:24 When, when we think about sugar, do we need to think beyond just actual table sugar that we might put in stuff or might be added to biscuits and cakes and pastries? Do we also need to be thinking, in your view, about blood sugar spikes? So for example, one teaspoon of sugar i- in, let's say, a hot drink. That probably is not gonna have as detrimental an impact or as significant an impact, I should say, on our blood sugar than, let's say, a modern, uh, healthy cereal or a cereal that's marketed as healthy, when we know that you have a bowl of those, you can have the equivalent of far more than just one spoon of sugar in.

Dr. Tommy Wood 41:11 Yeah.

Dr. Rangan Chatterjee 41:11 So I think sometimes when we think of sugar, we're not really t-- And maybe it's the way we communicate as healthcare professionals sometimes. It's not just sugar, is it? It's also foods that are turned to sugar-

Dr. Tommy Wood 41:23 Yeah

Dr. Rangan Chatterjee 41:23 ... in your blood.

Dr. Tommy Wood 41:25 So any, or the vast majority of carbohydrates will get converted to either are or get converted into glucose, which then will at least temporarily increase your blood sugar, uh, in response, and I think in general, that can be normal, right? We don't want to pathologize. That's another fancy word. We don't want to like create a disease out of spikes in blood sugar necessarily. Of course, there's lots of evidence that suggests that having better control of your blood sugar is associated with better-

Dr. Rangan Chatterjee 41:57 Mm

Dr. Tommy Wood 41:58 ... health outcomes. Um, particularly as you, you know, if people go into, say, pre-diabetes or type 2 diabetes, um, that's associated with a whole host of long-term chronic health conditions and, um, earlier mortality. Um, so if you can have better blood sugar control, that's as- that in general is associated with better health, and it, it particularly in those populations. If you're somebody who's otherwise very healthy and very active, and you once in a while eat something that causes a big, big spike in your blood sugar, I'm not convinced that's gonna have a big impact.

Dr. Rangan Chatterjee 42:28 Mm.

Dr. Tommy Wood 42:29 Right? It's all about the context like you talked about earlier. But you're right that anything that we eat that has carbohydrates in will s- will increase your blood sugar, um, to, to some degree. And there are, there's some evidence to suggest that if you can make that spike lower, and you can do that either by the timing of your foods. I, I know you've had episodes on this previously. Uh, maybe eating protein with your foods. There are other things that you can do to decrease the, the size of that blood sugar spike. Uh, and for some people that, that, that may be beneficial. The, the problem is that it's really difficult to predict what foods will do that.

Dr. Rangan Chatterjee 43:07 Mm.

Dr. Tommy Wood 43:08 Um, 10 years ago you would've talked about the glycemic index, right? So this is a food, it has a high glycemic index. That means when you eat it, you're gonna get big, big spike in blood sugar. What we've learned in the last five years is that that just doesn't hold from person to person.

Dr. Rangan Chatterjee 43:22 Yeah.

Dr. Tommy Wood 43:22 Right? You can have two people eat the identical foods, and one person will get a big blood sugar spike, and the other person won't get any spike at all. And then there was a, there's a recent study, it came out, it's, um, it's a preprint, so it's not formally published yet. It will come out as soon as, uh, by, by Kevin Hall, who's done all these-

Dr. Rangan Chatterjee 43:39 Mm

Dr. Tommy Wood 43:39 ... very complex metabolic ward studies in the US. And they, they had these trials where, um, they gave people a fixed, uh, a fixed menu, and they had a plant-based one, they had a, a low fat one, uh, a low carb one. Um, and the menu would cycle over a couple of weeks. So they would have... And then some of these, uh, some of the people in these trials wore continuous glucose monitors. And then because the menu rotated, they would get a, a blood sugar response to the same meal in the same person, but a week or two apart. And what they found was that eating the same meal in the same person resulted in completely different blood sugar responses from one week to the next, which just [laughs] tells us that we don't ... We, we have-

Dr. Rangan Chatterjee 44:27 Mm.

Dr. Tommy Wood 44:27 Like right now, we cannot predict what foods will, uh, spike our blood sugar. So even if we, we have our own ... I see you're wearing a continuous g-

Dr. Rangan Chatterjee 44:35 Mm

Dr. Tommy Wood 44:35 ... bl- uh, uh glucose monitor, um, that you, you can ... You have to test something out a lot-

Dr. Rangan Chatterjee 44:42 Yeah

Dr. Tommy Wood 44:42 ... again and again in yourself to, to see an effect, and even then there's gonna be a lot of variability. So then is that even meaningful or feasible for, for some people? It becomes, it becomes really difficult. Um, so I think, like managing blood sugar is obviously incredibly important, but right now it's just really tricky to navigate. And there's, uh, you know, Tim Spector's done some recent studies, uh, where they show that a whole bunch of things affect how you respond. So it's how did you sleep? What meal of the day is it? Like, what's your genetics? Like, have you exercised recently? There's a whole bunch of things that affect how we respond to foods and, and even in the same person, the same meal has, has different effects-

Dr. Rangan Chatterjee 45:21 Yeah

Dr. Tommy Wood 45:21 ... from one week to the next. So, um-

Dr. Rangan Chatterjee 45:23 But I think that speaks to what you said maybe when we were talking about alcohol or caffeine, that in a biological system, it's very rarely just one thing.

Dr. Tommy Wood 45:34 Yeah.

Dr. Rangan Chatterjee 45:34 Right? Because you're assuming that everything else in that system is identical when it isn't.

Dr. Tommy Wood 45:40 Yeah.

Dr. Rangan Chatterjee 45:40 And we're not the same person day to day. We, you know, uh ... F- anyone who has worn a continuous sugar monitor, and I think for some people that can be tricky to figure out, well, what does this actually mean for me? I feel I'm quite in tune with my body and I, I guess it's what I do, and I think about this and sort of pay attention a lot, and I, I certainly found for me that you can see correlations quite well where, you know, depending on if you haven't slept well.

Dr. Tommy Wood 46:06 Yeah.

Dr. Rangan Chatterjee 46:07 Y- your sugar's higher and you ... The same meal can give you a bigger response, or if I feel high levels of stress. I guess with everything we're talking about, we've done alcohol, caffeine, sugar, a bit on ultra-processed food so far as well. Are we not more and more moving into an N equals 1 era, whereby we can use science to give us good starting points and ideas, but ultimately we're gonna have to test these things out on ourselves and go, "Well, is this working for me?"

Dr. Tommy Wood 46:43 I, I think so, and that's ... You know, even going back, say, 50 years, um, this is in a slightly different arena, but looking at, um, elimination diets were once the, the gold standard for people with autoimmune, certain autoimmune conditions before we, we, uh, invented monoclonal antibodies for, for these things. And the only way to know if they worked was to, you know, change your diet and see how the patient responded, and you would do that individually. And-

Dr. Rangan Chatterjee 47:13 Mm

Dr. Tommy Wood 47:14 ... I think that's, that's where we, we really are at this point. The, the, the problem is that ... So say, um, if we go back to, back to blood sugar or we stay on blood sugar. I'm not convinced that the data is necessarily helpful for people. So say I, I, I don't generally recommend that people go out and get a, a-

Dr. Rangan Chatterjee 47:38 Mm

Dr. Tommy Wood 47:38 ... blood sugar monitor. Um, and one of the reasons is that it become ... And, and I've seen this several times when working with people, it becomes incredibly stressful.

Dr. Rangan Chatterjee 47:47 Mm.

Dr. Tommy Wood 47:48 So I'm gonna eat a piece of cake. I know that cake is gonna p- spike my blood sugar. I'm now stressed about-

Dr. Rangan Chatterjee 47:55 Mm

Dr. Tommy Wood 47:55 ... the blood sugar spike that I'm gonna see because of the cake that I'm, that I'm eating. Um, and you know, we've had people who've, who've come back and just ... We didn't really appreciate how much stress, like the, the idea of eating-

Dr. Rangan Chatterjee 48:10 Mm

Dr. Tommy Wood 48:10 ... and how that was gonna affect the, the data that they see was incredibly stressful to them. So, like, is that ... You know, at what point does, does that become harmful? And, and there are s- there are actually studies that show that the expectation of a blood sugar spike drives a bigger blood sugar spike. So-

Dr. Rangan Chatterjee 48:27 Mm

Dr. Tommy Wood 48:27 ... there was a study by Ellen Langer at Harvard where they took diabetics, and they gave them a milkshake, and they showed them how much sugar was in this milkshake. And it was a high sugar milkshake-

Dr. Rangan Chatterjee 48:38 Mm

Dr. Tommy Wood 48:38 ... and they saw a big blood sugar spike. And then later on they came back and they gave them a different milkshake. It was a low sugar milkshake, and they showed them that, and they had a lower blood sugar spike. It was the same milkshake both times, but they had a bigger blood sugar spike when they thought that it had more sugar in it.

Dr. Rangan Chatterjee 48:52 Biology and psychology.

Dr. Tommy Wood 48:53 Yeah. Biology and psychology coming together. So it just ... I think that, yes, the N equals 1 experiment is really important, but I think that rather than, like being hyperfocused on this one thing, which is blood sugar- Can you move yourself closer to a less processed diet, right? Increase vegetable, uh, consumption. Do I... So make vegetables a bigger part of your plate-

Dr. Rangan Chatterjee 49:20 Mm

Dr. Tommy Wood 49:20 ... or start with a bigger, uh, portion of protein on your, on your plate, right? That's gonna come with ... Both of those are gonna come with a whole bunch of nutrients and these other things. Um, and then maybe decrease the portion of whatever it is, whatever-

Dr. Rangan Chatterjee 49:31 Yeah

Dr. Tommy Wood 49:31 ... whether the refined carbohydrates or something. So I think that overall shifting your dietary pattern is much more important, and that doesn't need necessarily, unless there are different foods that you enjoy, as much n equals one experimentation. So I think we're at a point where you can, particularly with, with diet, you can give pretty good advice that's gonna work for a lot of people, and they don't need fancy tools-

Dr. Rangan Chatterjee 49:53 Mm

Dr. Tommy Wood 49:53 ... and they don't need fancy data, and they can still make a big impact on their health.

Dr. Rangan Chatterjee 49:57 Yeah. I appreciate your perspective on that, and I've always had a real caution with trackers. I guess the argument you're making around CGMs, continuous glucose monitors, I guess we could also make about, let's say, scales, for example-

Dr. Tommy Wood 50:12 Mm

Dr. Rangan Chatterjee 50:12 ... and weights. And I kind of feel a lot of this becomes personality dependent, whereby for some people, scales and their weights becomes incredibly obsessive-

Dr. Tommy Wood 50:23 Yeah

Dr. Rangan Chatterjee 50:23 ... and becomes problematic. And then for others, it's like, yeah, they can check once a week, and, "Oh, yeah, I'm going in the right direction." I've mentioned, I think before with you, that I saw the same thing with blood pressure monitors, which aren't like modern tech necessarily, but for half the patients it was great. For the other half, it was anxiety inducing.

Dr. Tommy Wood 50:41 Yeah.

Dr. Rangan Chatterjee 50:42 I guess where I see CGMs as being different is I kind of feel that they give a real... I, and I totally agree they can be overdone. I think if you've got a history of eating disorders, you've got to be very cautious. Probably not the right approach for you. But in the context of a population, as we say, maybe 60, 70% of the UK, maybe 90% in the US of the population having a degree of metabolic dysfunction, I think in that context, I personally believe we have to be open to tools that are gonna help people, because we've been asking people to make these choices for years, and I feel that we're still struggling. And a lot of that is because of our food environment, I know, but I don't think I've seen a better tool, Tommy, in over two decades of practice now, where ... I, I don't think I've seen a better tool that helps people start to change their diet in a meaningful way than a CGM. I don't think everyone needs them. But I would say from my own experience with people and also myself, I've found them to also to be very, very helpful. So that would be what I would say in response. So I think we have maybe a slightly different perspective on this, which is okay as well.

Dr. Tommy Wood 51:59 Uh, yeah, absolutely. And, and there are studies in type 2 diabetics that, uh, and again, early small studies suggesting that having a CGM improves their adherence to, um, say, a dietary intervention or dietary recommendation. So, so absolutely. Sometimes that can, you know, give people some accountability and help drive some behavior change. Um, yeah.

Dr. Rangan Chatterjee 52:18 And it's with like, let's say a step count on your watch or your, uh, phone. For some people it works great and it motivates them. Like, "Oh, I didn't get my 7,000 today. Uh, 7,000's my target, so I'm gonna go ... I'm only at 5,000. After dinner I'm gonna go for a walk around the block." But for other people it becomes an obsession and problematic. So I think, again, you know, relating this to alcohol and caffeine and sugar, I'd say kind of, I think it depends a lot, and I do think we can overdo these things. And I, I do, you know, as I, I think I mentioned last time, I, I did wear an Oura Ring a few years ago, but I haven't worn one in years now because I kind of learned what I needed.

Dr. Tommy Wood 52:57 Yeah.

Dr. Rangan Chatterjee 52:58 I, I kind of ... Oh, I get it. If I eat near bedtime, sleep quality goes down. Okay, great. If ... I saw a few other things, and I, I don't really feel I need it anymore. I learnt what I did. And I kind of feel for some people, like you wear a CGM once for two weeks, and you have your regular foods, and you're like, "I had no idea that that does that to me, and no idea." I think for some people, that's all they ever need.

Dr. Tommy Wood 53:21 Yeah.

Dr. Rangan Chatterjee 53:21 You know? So yeah, this, this will be continued, I'm sure, as we see this evolve over the coming years.

Dr. Rangan Chatterjee 53:28 Protein. I think there's a lot of confusion about protein, and there's a lot of talk in the longevity space about the optimal amount of protein that you need, uh, for your muscle mass, um, which is important for longevity, and I don't disagree that muscle mass is important for longevity. There's also advocates for low protein diets, and I think this is a, one of those areas where there's a lot of debate about, and I think it leaves people feeling confused. So how do you view protein, and what kind of recommendations do you make to the people that you see? We'll be back to the conversation in just a moment. Now, many of us struggle to find time to eat all of these incredible whole foods. That's why I'm a big fan of good quality whole food supplements like this one that's been in my own life for over three years now. It contains over 75 whole food source ingredients, vitamins, minerals, pre and probiotics, and can help us support our energy, focus, digestion, and our immune system. AG1 are giving my audience a fantastic offer, one year supply of vitamin D and five free travel packs with your first order. You can see all details at drinkag1.com/livemore, or just click on the link below. And now, back to the conversation.

Dr. Tommy Wood 55:01 I generally think that people under eat protein, um, at the population level, and part of that is driven by The types of foods that they eat, which tend to be low protein. Um-

Dr. Rangan Chatterjee 55:14 Could you just explain population level-

Dr. Tommy Wood 55:16 Yeah. So-

Dr. Rangan Chatterjee 55:16 ... in case people don't get it?

Dr. Tommy Wood 55:17 Yeah. So if you, if you were gonna ... If you're gonna look at how people eat in the US or the UK on average, um, so that's the population level, uh, how much protein are they eating? And I, in general, I think people eat too little, particularly as they get older. When you look at some of the evidence around protein intake and longevity, there's two broad streams of evidence. One is animal data. A lot of it's from mice, and, um, I mentioned this last time I was on the podcast, I do animal research for a living. That's what pays the bills, and most animal research is not useful for humans at all. I think most of it's a complete waste of time. Um, and I would include most dietary studies in rodents, if I'm honest. Because rodents are not small humans, and we have seen again and again how, um, these kinds of studies fail to translate to humans. So if you feed a mouse, which doesn't normally eat a high protein diet, a high protein diet, you may see some negative effects on their health. That doesn't necessarily ... That tells you that you shouldn't feed mice a bunch of protein. It doesn't tell you [laughs] whether you should feed humans more protein, and humans evolutionarily consumed a lot more protein. Like, in addition to being gatherers, we were hunters, and it made up ... Like, animal protein made up a large proportion of our diet, and our ... We are ... Our digestive system and our metabolism is in tune with that, and, you know, that ... I think that, that's an important consideration. Like, what are we, what are we looking at to try and tell us some of this? The other type of information or studies that we get are usually epidemiological studies. So we ask people how they eat, and then we look at how long they live or what diseases they get later on. There are two problems with that. One is that people are really bad at telling us how they eat. Um, so, uh, there's one classic study on protein and cancer and longevity, came out in Cell Metabolism, um, um, nearly 10 years ago, and they talked about how, you know, low protein was beneficial early in life, and then higher protein was beneficial later in life. Um, and they used, uh, s- there was some mouse data, and then there was some, some human data, and they used a, a study called NHANES, the National Health and Nutrition Examination Survey in the US.

Dr. Rangan Chatterjee 57:48 Mm-hmm.

Dr. Tommy Wood 57:48 Where they call pe- they call up a few thousand people every year and they say, "What did you eat in the last 24 hours?" And then they say, um, you know, z- so you tell them, and then they're like, "Are you sure you didn't have any ice cream? Are you sure you didn't have a beer?" Right? So, like, things that people just tend to underreport, and then that's it. That is then assumed to be their diet every day, and ... Well, they also ask them how typical it was, right, um, for their diet, and then they look at how long they live 20 years later. And there have been some studies on NHANES data in particular. Um, there was, there was a nice paper that came out that said that the majority of dietary responses in NHANES were not physiologically plausible. As in these people, based on how tall they are, how much they weigh-

Dr. Rangan Chatterjee 58:34 Mm

Dr. Tommy Wood 58:34 ... their physical activity levels, what they've told us they eat cannot physically be correct. It is physiologically implausible that they're eating this amount. And we're using that, we're using the protein intake from that study to say, "This is how, you know ... You know, th- this is how protein affects your health." When in reality we have no idea what these people are eating. So the ... A lot of the data that comes from, um, that, that is being used to make recommendations, particularly to eat low protein, is just so highly flawed that I just wouldn't even look at it. I'd, I ...

Dr. Rangan Chatterjee 59:05 Mm.

Dr. Tommy Wood 59:05 It's not even worth ... It's what? Not even worth considering. So then you might think about, what about some interventional data, right? We have, um, people, and we change the amount of protein that they eat, and then we, we look at some outcomes.

Dr. Rangan Chatterjee 59:19 Can you just explain interventional data as well?

Dr. Tommy Wood 59:22 Yeah. So int- interventional means that there's some people who come in for a study, and we physically change something, and then we track responses over time. Um, rather than just asking somebody what they eat, and then, you know, assuming that it's correct and, and, and looking at the long-term outcomes. And particularly as individuals get older, we know from interventional studies where we have, you know, looked at them, and we've fixed the amount of protein that they, that they eat or increased the amount of protein they eat, and then we look at their outcomes. That as you get older, in order to maintain muscle mass and strength, which ... And particularly strength, which is a critical component of long-term health, older people need more protein. And in general, as we get older, we tend to eat less protein. We, we tend like-

Dr. Rangan Chatterjee 1:00:08 Mm.

Dr. Tommy Wood 1:00:08 Often, um, hunger decreases, and protein is very satiating, and so the protein intake decreases over time. So not only do we eat less, we also need more, relatively.

Dr. Rangan Chatterjee 1:00:19 Mm.

Dr. Tommy Wood 1:00:19 Um, and so in general, I think particularly as people get older, um, they, they have a relative protein deficiency, and that affects a, a whole bunch of things, right? That affects gut function because you have a high turnover of cells in your gut. You need protein to replenish those. Um, it affects, uh, muscle function, probably cognitive function. You know, the amino acids are really important, uh, for neurotransmitters and all these other things. So in general, I think most people under eat protein. Um, and there have been studies where they give people vast amounts of protein and see almost no negative effects on their health, like four grams per kilo. So that'd be me, like, eating 400 grams of protein. That's a heroic amount. That's a huge amount of protein. I would never eat that much protein.

Dr. Rangan Chatterjee 1:00:57 Heroic. [laughs]

Dr. Tommy Wood 1:00:59 But in these studies, they were ... They're eating that for a year or two. It has no negative effects on, on any blood markers or a- or, or anything.

Dr. Rangan Chatterjee 1:01:05 What, what about these rumors that high protein diets are problematic for our kidneys? Where does that come from?

Dr. Tommy Wood 1:01:12 So, so one of the things is that if you, if you overeat protein above your requirements, you will ... your kidneys will have to work harder to excrete the extra nitrogen, which is-

Dr. Rangan Chatterjee 1:01:21 Mm-hmm

Dr. Tommy Wood 1:01:21 ... which is from that pro- but that's, that's part of what the, the kidneys do. That's, that's part of their job.

Dr. Rangan Chatterjee 1:01:26 Mm-hmm.

Dr. Tommy Wood 1:01:26 Um, in people who have normal kidney function, so if you have chronic kidney disease and/or, you know, you're on the way to or, or need dialysis, it's a completely different question.

Dr. Rangan Chatterjee 1:01:38 Yeah.

Dr. Tommy Wood 1:01:38 Right?

Dr. Rangan Chatterjee 1:01:38 For sure.

Dr. Tommy Wood 1:01:39 Uh, you absolutely speak to your renal team. That's, that's the important thing you need to do. But for people with, with normal healthy kidneys, eating, you know, there's no negative effect of, of protein intake on kidney function. I'm not actually entirely sure where that rumor-

Dr. Rangan Chatterjee 1:01:52 Originally came from

Dr. Tommy Wood 1:01:52 ... originally came from.

Dr. Rangan Chatterjee 1:01:53 Yeah.

Dr. Tommy Wood 1:01:53 But there's, there's really no evidence t- to, to support that.

Dr. Rangan Chatterjee 1:01:56 I really appreciate that. Whenever I come across conflicting bits of information or, let's say, different health experts giving advice on the same topic but completely different bits of advice, which again, is one of the reasons I wanted to have this conversation because I think there is a lot of confusion where people go, "Wait a minute, this expert who I really like and respect said this. This other expert, who's also a medical doctor, also a scientist or a researcher, said the complete opposite. I don't know what to do anymore."

Dr. Tommy Wood 1:02:28 Mm-hmm.

Dr. Rangan Chatterjee 1:02:30 The way I look at that often is I, I go and trust what I've seen time and time again with patients.

Dr. Tommy Wood 1:02:38 Mm-hmm.

Dr. Rangan Chatterjee 1:02:39 Right? It's because, as you said before, you can actually find a lot of science to support both sides often-

Dr. Tommy Wood 1:02:45 Yeah

Dr. Rangan Chatterjee 1:02:45 ... of an argument, which gets really, really confusing. But what I know is that I, I have seen over ... You know, I've seen tens of thousands of patients, and I've been applying these lifestyle principles for many, many years. And whilst I would always say there's very rarely one approach that works for everyone, there are some common principles that I've seen work time and time again. One of them being in this modern food environment, I think that also comes into it, right? When and where are we studying people? In the context of a food environment which is highly problematic and full of ultra-processed foods everywhere we go, encouraging us to eat too much and for too long a period over 24 hours, I've found honestly that increasing our protein intake for many people really helps them get back on track.

Dr. Tommy Wood 1:03:36 Yeah.

Dr. Rangan Chatterjee 1:03:36 It helps them feel fuller. It helps them eat less overall. And so I guess my bias would be that I've seen that work over and over again.

Dr. Tommy Wood 1:03:46 Yeah.

Dr. Rangan Chatterjee 1:03:47 So for me, it's a helpful recommendation. I think most people benefit from a bit more. But then what does that mean? Because you will hear things like some people say 1.8 grams of protein per kilo.

Dr. Tommy Wood 1:03:59 That's more ... That's ... I think that's more than you need.

Dr. Rangan Chatterjee 1:04:02 The ... I do because-

Dr. Tommy Wood 1:04:03 Yeah

Dr. Rangan Chatterjee 1:04:03 ... if I apply that to myself, right? I'm almost six foot seven. I weigh, I don't know, I, I really don't weigh myself, but I'm probably somewhere between 95 and 100 kilos. Let's call it 100 kilos for simple maths. That's like 180 grams of protein a day. That ... I think that feels pretty heroic as well, right?

Dr. Tommy Wood 1:04:21 [laughs]

Dr. Rangan Chatterjee 1:04:21 That's, that's a lot of protein. Now, you may say, actually, for your height and frame, that's fine. But, you know, I, I never really like giving ... getting into, you know, grams per kilo.

Dr. Tommy Wood 1:04:33 Yeah.

Dr. Rangan Chatterjee 1:04:33 But I do, I do accept for some people it's helpful. Do you have a recommendation about that?

Dr. Tommy Wood 1:04:40 So I think the, the general recommendation, and there's been, um, you know, lots of different meta-analyses and these other things that, that, that look at, you know, how well do you respond in terms of, and again, like muscle mass and strength, I think those are a nice hard outcome that we know are associated with, with long-term health outcomes, at the same time not seeing any negative effects. And in general, it pro- it's probably somewhere around 1.2 to 1.5 grams per kilo, say. Uh, there was a meta-analysis that looked at strength responses in, uh, younger and older individuals and the, the optimal amount of protein intake from, again, interventional studies seems to be about 1.5. But there have been other studies that compared like 1.3 to 1.7, and they see sim- they see similar responses. So it's somewhere in that, in that kind of range. Um, and in, in general, what that means is that if you have three or four meals a day or, you know, three or more periods of where you intake some calories, that each of those contains something like 20 to ... or 30 to 40 grams of, grams of protein. And you can figure out what that looks like in terms of a cut of steak or salmon or, or eggs or, or tofu or, or yogurt. Um, you know, there's some strained Greek yogurts that have a, a high protein content. And that, that ... And I think that's how you should ... In the way that I would work with people is th- that's, that's the basis of the meal. That comes first, and then things come aro- because that's the most ... probably gonna be the most critical single component that you want to consistently make sure you're, you're consuming because the, the fats and the carbs and things, they can kind of go up and down and around, but I think the pro- the protein, I would recommend be relatively consistent and in that range. And relative to what you mentioned earlier, as I say, there was another study, uh, by Kevin Hall that I mentioned earlier, where they had people consume, uh, either an ultra-processed versus a, a minimally processed diet. And they, they have them in the lab, and they, they can eat as much as they want, and they c- you know, they measure all, uh, everything that they eat, and they can follow them, you know, for several weeks at a time. And even though they matched for like fiber and these other things in the diets, those who were eating ultra-processed foods saw ... And it was ... If you look at it, it's just like typ- it's just like, uh, cereal, uh, sandwiches, bread, right? Just typical. Those are-

Dr. Rangan Chatterjee 1:07:06 That's the standard diet for many people

Dr. Tommy Wood 1:07:08 ... stan- stan- standard diet. Um, those individuals on that diet ate about 500 calories more on average per day, 400 to 500 calories more per day, and ... But the protein ... was consistent in the two diets. So the idea is it comes to this idea of something called the protein leverage hypothesis-

Dr. Rangan Chatterjee 1:07:25 Yeah

Dr. Tommy Wood 1:07:25 ... which is that you continue eating until you reach a certain protein threshold that your body needs. And so most, like I said, ultra-processed foods are low in protein, and part of what's driving you to eat more of them is to get up to some protein requirement. So an easy way to get around that is to make protein the focus of a meal, and then you will be more satiated and you're less likely to overeat in response.

Dr. Rangan Chatterjee 1:07:51 There are some proponents, uh, I think of having a minimum of 30 grams of protein, particularly after, let's say, an overnight fast. I think someone like Gabrielle Lyon, for example, or Don Layman would promote a minimum of 30 grams to make sure you're getting the minimum requirement of leucine that's needed to, to build muscle.

Dr. Tommy Wood 1:08:12 Yeah.

Dr. Rangan Chatterjee 1:08:13 You mentioned before, I think 20 to 40 grams, and-

Dr. Tommy Wood 1:08:17 The 20 being there are some people who are a lot smaller than you or I, so 20 would be just fine. So that's, that's where-

Dr. Rangan Chatterjee 1:08:23 Got it

Dr. Tommy Wood 1:08:23 ... that range starts to come into play.

Dr. Rangan Chatterjee 1:08:24 Fine. So 20 to 40 grams-

Dr. Tommy Wood 1:08:26 Yeah

Dr. Rangan Chatterjee 1:08:26 ... basically you're saying should be the mainstay of most people's meals, and that will depend whether you're slight or whether, you know, if you're very tall and large. Well, if you're very tall like me [laughs] uh, it's probably gonna be more towards 40 grams.

Dr. Tommy Wood 1:08:40 Yes.

Dr. Rangan Chatterjee 1:08:41 Okay. So helpful, and I also love what you said before that there really isn't that much evidence that high protein diets. If you have too much, you're not really causing harm.

Dr. Tommy Wood 1:08:50 No.

Dr. Rangan Chatterjee 1:08:51 Your kidneys will just have to get rid of it.

Dr. Tommy Wood 1:08:52 Yeah.

Dr. Rangan Chatterjee 1:08:53 Fine. Well, let's just talk about

Dr. Rangan Chatterjee 1:08:55 exercise and movement. I think there is a lot of confusion about exercise. What's the state at play?

Dr. Tommy Wood 1:09:01 [laughs]

Dr. Rangan Chatterjee 1:09:01 Okay, we have a sedentary population, right, who are not moving enough. There's a lot of talk these days about different types of exercise, different zones of exercise. There's talk of HIIT training, high intensity training, walking, and then, you know, I talk about it as different gears of movement. So gear one might be walking around the block. Gear two, very much equating to your car, you're going a little bit faster perhaps and there's a lot of talk about the unique benefits of what is being called zone two training, and some of the advice around that I think is gonna be very unachievable for many people.

Dr. Tommy Wood 1:09:43 Mm.

Dr. Rangan Chatterjee 1:09:43 So let's try and break it down. What's your current perspective on movement and what we all should be doing?

Dr. Tommy Wood 1:09:51 I think I said something like this last time and I, I still feel exa- I still feel the same, which is that whatever you can do that's more than what you're currently doing is great. Um, until you get to the ver- ... And then the ... I, I remember some comments of people going in like, "Oh no, people shouldn't lift weights 'cause they're gonna get injured." Well, actually lifting weights in a, in a, like a bodybuilding style is one of the safest forms of exercise you can do in terms of injury risk. And then some people said, "Oh yes, but you can get to a point where you're doing so much exercise that it's detrimental." And yes, of course that's the case, but like I'm, I'm not worried about ... I'm not talking about people exercising 30 hours a week, right? I'm talking about somebody going for a walk for 20 minutes a day. Um, and so th- so whatever you can do sustainably above what you're currently doing or previously have done will benefit your health, and I think, you know, that could be steps per day. Uh, it could be, you know, amount of time, amount of time you spend going for a jog or cycling or, or lifting weights or any kind of resistance training or anything like that. So, um, if you look at, say, the, the amount of physical activity that significantly improves certain health outcomes, so you know me, I often think about the brain. Um, so the amount of physical activity that significantly improves cognitive function, been large meta-analyses have looked at this. It's basically it doesn't, um, matter exactly what type you do, but if you're achieving, say, government physical activity guidelines, which is 150 minutes per week of moderate to vigorous physical activity, that is associated with a statistically significant improvement in cognitive function, and you can break that up however you like. You could do, uh, 30 minutes of brisk walking a day. You could do 20 minutes of Pilates a day. You could do 30 minutes of resistance training a day. You could do five minutes of sprinting per day. The way that it works in general at the simplest level is intensity times time. So the more intense, the less time you need. The less intense, the more, the more time you need. So you can, like one day you can go do a l- little bit of sprinting in the park if you want, or you can go for a brisk walk, or you could do an hour of gardening, right? That's even less intense, but even that's gonna have some benefits. So incrementally improving this sort of intensity times time, this volume that you're doing in any of those activities is gonna be beneficial, and like that, that's honestly where I start. And if you want to then dig into resistance training versus ir- endurance training, all those other things, we can do that, but the most important thing is that you do some movement every day, and if you're sedentary right now, literally anything that you can get up and do is, is gonna be beneficial.

Dr. Rangan Chatterjee 1:12:32 Okay. That's really useful and really empowering I think for people. What you said about intensity there is really, really interesting. So by what measurement or through what lens are you saying that one hour's gardening might be equivalent to five minutes of sprinting? Because we could probably measure that in a multitude of different ways-

Dr. Tommy Wood 1:12:56 Mm

Dr. Rangan Chatterjee 1:12:56 ... or look at various aspects of that to try and compare them. How are you comparing them when you say that they're the same?

Dr. Tommy Wood 1:13:02 So in general, when that's done, they use something called the metabolic equivalent or MET.

Dr. Rangan Chatterjee 1:13:09 Yeah.

Dr. Tommy Wood 1:13:10 And you can, you can Google, uh, there's, there's a PDF of METs for different activities, and it's very long. Like literally, um, every intensity of pretty much any activity you could think of, it gives you an average MET, and of course that's ... If I go sprinting It's a very different number of METs than if you go sprinting, but it just gives you an idea of the overall in- intensity of that activity. And so then, if I think about the cognitive function study, what they looked at was how many MET minutes per week. So again, that's intensity times time. What do you need to do per week to see a significant improvement in cognitive function? And it was about 700, which then, you know, with a little bit of back of the, back of the envelope calculation, is about the physical activity-

Dr. Rangan Chatterjee 1:13:54 Mm

Dr. Tommy Wood 1:13:54 ... the general government physical activity guidelines. So that's how... And when you look at that, that kind of says that, you know, overall, those, those are gonna have equivalent benefits. And when, then when you look at, say, harder outcomes like VO2 max, which is a, a measure of how efficient your cardiovascular system is, that's sort of the gold standard, then yes, there's probably some protocols that improve VO2 max a little bit better than others, but if you look across all the studies that have been done, in general, you see the same trend, that it's intensity times time. So if you do very intense, uh, work for a short period of time, that has a similar benefit to a less intense, uh, a, a period of exercise for, for a longer period of time. And again, this is, you know, if we're just thinking about normal people trying to move and improve their health, I think that's really the, the, the, the main important principle that it would boil down to.

Dr. Rangan Chatterjee 1:14:46 Cou- could we take that to an extreme? Let's say there's someone listening who, for whatever reason, doesn't move much at all.

Dr. Tommy Wood 1:14:52 Mm.

Dr. Rangan Chatterjee 1:14:52 They get to work, do their desk job all day, come home, uh, uh, sat down at home, and struggles with motivation to move their bodies, or time or whatever it might be. If they every day did five minutes of sprinting as hard as they could, let's say, let's say a few intervals, maybe, I don't know, 20 seconds of sprinting, 40 seconds recovery walking, 20 seconds of sprinting, right? And they do that for five minutes. Well, that's a pretty intense workout.

Dr. Tommy Wood 1:15:17 Yeah.

Dr. Rangan Chatterjee 1:15:18 Whereas someone else says, "You know what? I'm gonna go for an hour's walk every day, a nice gentle walk every day." And I know there's other benefits, nature, stress reduction, time away from your work. It gets really complex if we're trying to look at all those different things. But from a pure movement perspective on the body, are we saying through one lens they're pretty similar?

Dr. Tommy Wood 1:15:38 Essentially, yes. Um, assuming that you find some way to match the total amount of work that those two people are doing-

Dr. Rangan Chatterjee 1:15:45 Mm

Dr. Tommy Wood 1:15:45 ... which you can through, like, a intensity times time lens.

Dr. Rangan Chatterjee 1:15:49 Mm.

Dr. Tommy Wood 1:15:49 In general, I think they're both going to improve their health, and it's gonna be really difficult to separate out one-

Dr. Rangan Chatterjee 1:15:56 Mm

Dr. Tommy Wood 1:15:56 ... versus the other.

Dr. Rangan Chatterjee 1:15:57 Yeah. It's really, really interesting and empowering for people. So that's a sedentary population, right? Where you're going, okay, anything is better than nothing.

Dr. Tommy Wood 1:16:05 Yeah.

Dr. Rangan Chatterjee 1:16:05 You're getting a huge improvement if you go from nothing to something. What about for people who I guess have a bit more time or are already active? Let's say they're already able to go for a 30-minute walk seven days a week. They're like, "Tommy, look, I, I can do that. That's no problem. My, my life and my work allows me to do that.

Dr. Rangan Chatterjee 1:16:27 What else should I be doing as I get older to, you know, look after my health, body, brain, mind, everything?" Where would you go next?

Dr. Tommy Wood 1:16:37 Resistance training of some kind. There's some kind of weightlifting or something where you're applying resistance to, to the muscles. I... You know, there's lots of different ways that you can think about this. Uh, in general, um, I think there's a... I have a pyra- a movement pyramid. It's my own movement pyramid. And, and I think at the, at the bottom is just spending less time sitting, right? So there's even, there's even benefits to, um, you know, getting a standing desk if you, if you can. Also, say, say you're in, you're in a job where you're sitting all day. Is there some way to make it so that you're just sitting less? And that could even be this idea of movement snacks where, you know, once an hour you go for a quick walk or you go up and down some stairs or wh- whatever you can do near you. So just less time sitting. Um, and then the next would be spend more time walking.

Dr. Rangan Chatterjee 1:17:31 Mm-hmm.

Dr. Tommy Wood 1:17:31 And there's a whole bunch of studies again suggesting that brisk walking, um, and particularly in those who are, who are otherwise sedentary, can dramatically improve, um, your health, and there's this linear benefit of number of steps you can get per day in terms of mortality risk and dis- and various disease risk up to maybe somewhere between 8,000 and 14,000 steps per day or something. But the more you can do in that 0 to 10,000 or 12,000, the better really. And a lot of that, if, particularly if you're doing quite brisk walking, so say you're doing your 30 minutes and it's quite brisk, um, then that for many people may be getting them up into that area that you mentioned, briefly mentioned earlier, that zone two, so you're getting some of those cardiovascular benefits, and that's probably where a lot of that benefit comes from. So then the next level I think is, is resistance training. Um, and particularly as you get older, we know there's a decrease in muscle mass, but more importantly, and probably faster and earlier, there's a decrease in strength. And as you get older, you lose, in particular, type2 muscle fibers. These are fast twitch muscle fibers, and those are important for a number of reasons because they're, they're an important glucose sink, so they're important for metabolic health, right? So if you're talk... We talked earlier about all these things that affect your blood sugar.

Dr. Rangan Chatterjee 1:18:49 Mm.

Dr. Tommy Wood 1:18:50 Having healthy, active muscles and having a lot of these types of fibers is really important for our blood sugar control and a whole host of other things. Um, and it's also really important for our stability and mobility and function. So if you lose those fast twitch fibers, those are the ones that are important for, like, reactions and, like, if you, uh, if you, like, are gonna fall, like grabbing onto a handrail or stopping yourself from falling. And, you know, particularly as you get older, you know, f- falls risks and, uh, broken hips and all that kind of stuff, you're gonna be protected against that if you have more of those types of muscle fibers, and those are the ones that you get through resistance training. They're the ones you develop in, in particular. You know, it, it affects all the mu- all of your muscle tissue, but those are the ones that you protect when you do that kind of resistance training

Dr. Rangan Chatterjee 1:19:35 I wonder if we could just spend a bit of time trying to define resistance training. Uh, and the reason I'm asking this question is some people don't wanna go to the gym.

Dr. Tommy Wood 1:19:44 Mm.

Dr. Rangan Chatterjee 1:19:45 And, you know, given that gyms are a relatively modern phenomenon-

Dr. Tommy Wood 1:19:49 Mm-hmm

Dr. Rangan Chatterjee 1:19:49 ... and that humans have lived to pretty decent ages for a long period of time, I think when we say resistance training or strength training, we have to broaden it out beyond lifting weights in a gym.

Dr. Tommy Wood 1:20:02 Yeah.

Dr. Rangan Chatterjee 1:20:02 'Cause for the people who love that, they love hearing it and go, "Yeah, I knew I was on."

Dr. Tommy Wood 1:20:06 [laughs]

Dr. Rangan Chatterjee 1:20:06 "It was strength training," right? But for people who don't like it, it can be a bit confusing. So indoor climbing, running up hills, right?

Dr. Tommy Wood 1:20:15 Yeah.

Dr. Rangan Chatterjee 1:20:16 You know, that's resistance against gravity. In your view, what counts as resistance training?

Dr. Tommy Wood 1:20:26 So it, it can be ... It, it's literally any movement where you're, you know, you're moving your body in space against, so against something that makes it harder than it normally would be for that movement, if that makes sense. Right. So-

Dr. Rangan Chatterjee 1:20:40 So, so carrying your shopping bags to your car or even to your home, or is that resistance training?

Dr. Tommy Wood 1:20:46 Yeah.

Dr. Rangan Chatterjee 1:20:46 'Cause instead of walking-

Dr. Tommy Wood 1:20:46 Absolutely

Dr. Rangan Chatterjee 1:20:47 ... you're, you're carrying, right?

Dr. Tommy Wood 1:20:48 Yeah. And we've talked previously about, so you mentioned the blue zones, and in the Nicoyan Polin- peninsula, they're not all down the gym all day, right? Um, but they are doing physical activity every day that includes things like carrying and lifting. Um, and so ... And you can translate that to your own activities of daily living, as we call it, right? So if you wanna be able to carry your shopping, um, then heavy shopping bags are resistance training. Um, and any time that you're moving your body, and so it could be squats just with your body weight, that's resistance training. Or, you know, you could do pushups, and it can be against the wall rather than against the floor. You know, that, that's resistance training. Um, and, and it can just be these daily activities like lifting things into cupboards and carrying things around. Like, all of that counts, and particularly as you get older, you want to maintain those, you want to maintain-

Dr. Rangan Chatterjee 1:21:43 Mm

Dr. Tommy Wood 1:21:43 ... those functions. So anywhere you can find an opportunity to move your body against some kind of resistance, that counts. The, the problem, you know, does become at some point you need to progress things.

Dr. Rangan Chatterjee 1:21:58 Mm.

Dr. Tommy Wood 1:21:58 So in order for it to create ... Again, anything is better than nothing, but to create an ongoing stimulus, it has to be a l- I think it has to be a little bit challenging.

Dr. Rangan Chatterjee 1:22:10 Mm.

Dr. Tommy Wood 1:22:10 So, you know, if you're just gonna ... So m- so maybe, uh, you do a few, uh, calf raises, squats, pushups against the wall, a few bicep curls in the kitchen. Like, all of that stuff is great. Um, but at some point you have to make sure that you're ... You, you would like to progress. It would like to be ... You would like to get stronger, such that that is no longer enough, and then you have to find some way to make it, uh, a little bit harder. So th- I think there has to be a challenge component to it as well.

Dr. Rangan Chatterjee 1:22:37 So the pushup against the wall then has to be the pushup against the table.

Dr. Tommy Wood 1:22:40 Yeah.

Dr. Rangan Chatterjee 1:22:41 And then the pushup against the chair, and then-

Dr. Tommy Wood 1:22:42 Yeah

Dr. Rangan Chatterjee 1:22:43 ... a few months later, maybe pushup on the actual floor.

Dr. Tommy Wood 1:22:45 Yeah, exactly.

Dr. Rangan Chatterjee 1:22:46 Um, and also I think I just wanna highlight, let's say yoga and Pilates, for example.

Dr. Tommy Wood 1:22:50 Oh, absolutely. Yeah.

Dr. Rangan Chatterjee 1:22:51 Because sometimes I feel that gets left out of strength training, and I think, uh, participants, uh, and teachers of those disciplines will often say, "Hold on, a lot of what we do is, is hard on the muscles."

Dr. Tommy Wood 1:23:05 Yeah.

Dr. Rangan Chatterjee 1:23:05 You know? And there are plenty of yoga moves, for example, or Pilates moves, which I think do count as resistance training.

Dr. Tommy Wood 1:23:10 Oh, yeah. I think they absolutely should be included, particularly for, for, for this kind of discussion. Um, that ... I mean, there's a lot of yoga stu- You know, I, I'm relatively strong. There's a lot of yoga poses and things that I can't, I can't do. It's a different-

Dr. Rangan Chatterjee 1:23:24 It's different.

Dr. Tommy Wood 1:23:25 It's different, but it definitely counts as re- as, uh, as resistance, absolutely.

Dr. Rangan Chatterjee 1:23:29 Is there a next rung on your pyramid?

Dr. Tommy Wood 1:23:32 Yeah. So then the, the next rung, um, is high, is sort of high, is high-intensity interval training, or HIIT. And the reason why it's next is because I think that ... And again, this is for, um ... This is not for elite sports performance. This is just for average people who wanna try and figure out how to, uh, separate out their time in terms of movement. And so you will get some cardiovascular benefit from your brisk walking and it ... or it could be, it could be cycling or, or, or something, right?

Dr. Rangan Chatterjee 1:24:01 Yeah.

Dr. Tommy Wood 1:24:01 It doesn't, it doesn't have to be walking, but I, I like walking 'cause anybody or most people can do it. Um, but then you do get some slightly ... You know, if, if you then want to get into the physiological, biochemical nitty-gritty, you do get different adaptations to high-intensity training versus lower intensity training, right? I think in general, that idea of intensity times time is what's most important, but of course different things happen at the cellular level when you do-

Dr. Rangan Chatterjee 1:24:27 Mm

Dr. Tommy Wood 1:24:27 ... one versus the other. And so you can ... You know, that, that's, that's a beneficial add-on, uh, on top of, say, resistance training if you're already doing some, some low level, uh, intensity movement. And then on top of that, um, you know, if you, if you really enjoy it, I think you can do very long periods of, of endurance training. But it, but, but I don't think most people need that if they're just trying to move as much as they, as they can or to improve their health. So that's kind of the ... That's the progression that I use.

Dr. Rangan Chatterjee 1:24:55 Yeah. So, so I really like that. Um, if someone's hearing that and, and says, "Okay, Tommy, look, I don't move much. I like that pyramid, but do I have to sequentially go up it?" Or for example, if someone goes, "You know what? I used to do some strength training while I was at school, but I haven't done it in ages, and I quite fancy that." There's no reason why they can't start there, right, on your pyramid?

Dr. Tommy Wood 1:25:18 No.

Dr. Rangan Chatterjee 1:25:18 They don't have to progress up.

Dr. Tommy Wood 1:25:20 Yeah. And, um, what's, what's quite good about, say, say if you're going to the gym, is there's, there's a lot of ... You start doing the other stuff as well. So when you're, when you're at the gym, you're usually not ... like sitting like you would in, in, in a, in a chair at a desk or on the couch or on the sofa, and you're probably walking around quite a bit, right? You're, you're getting some of that, you know-

Dr. Rangan Chatterjee 1:25:40 Mm

Dr. Tommy Wood 1:25:40 ... additional m- movement. And, um, there are some, some nice papers that talk about how particularly if you do weight training to what they call voluntary muscular failure, right? So you do a number of-

Dr. Rangan Chatterjee 1:25:52 Mm

Dr. Tommy Wood 1:25:52 ... repetitions to the point where you can't do any more with good form. Even that has some cardiovascular benefits, right? You know, similar to maybe some, some l- lower, lower intensity, uh, aerobic training. So yeah, I think, you know, anywhere in that there's, there's, there's a, um, there's a good entry point for you, I think is, i- is great, and that's always where I would want people to start. The reason why I have, like, very long, hard endurance exercise at the top is 'cause that's often where people start, because that's where they assume they need to be in order to-

Dr. Rangan Chatterjee 1:26:22 Mm

Dr. Tommy Wood 1:26:22 ... improve their health, right? If I'm gonna g- I need to go for a run, it needs to be hard, and I need to do it for an hour, or else there's no point in doing it. But actually that's, that's quite taxing on the body, and you don't necessarily get all the, the other benefits that you would from those other different types of, uh, types of training. So that's why I put it at the top.

Dr. Rangan Chatterjee 1:26:39 Yeah.

Dr. Tommy Wood 1:26:39 But there's other... There's, there's lots of other places that people can enter, and again, anything that you can do that you enjoy and is sustainable, that's the p- place to start.

Dr. Rangan Chatterjee 1:26:47 And the other thing I, I guess I'd wanna add there is we forget sometimes that exercise and high intensity exercise can be a stressor-

Dr. Tommy Wood 1:26:55 Yeah

Dr. Rangan Chatterjee 1:26:55 ... on the body. And what I've, I've often seen with certain patients is they have very high stress lives. Go, go, go, and then the workout is also, you know, high intensity at a fast one-hour run. That is very hard on the body.

Dr. Tommy Wood 1:27:12 Mm.

Dr. Rangan Chatterjee 1:27:12 And I've... I think, again, this is a much broader conversation, so we will have to save this for another time, but I do think we also need to think about how much is this exercise now taxing us.

Dr. Tommy Wood 1:27:24 Yeah.

Dr. Rangan Chatterjee 1:27:25 And I certainly have found over the last couple of years, I've really been leaning more into a lot of low intensity, you know, walks or bikes or swimming where, you know, it's just nice and relaxed, but I'm going for 30, 40 minutes, maybe an hour. I'm like, "Wow, I, I feel like I need no recovery."

Dr. Tommy Wood 1:27:43 Yeah.

Dr. Rangan Chatterjee 1:27:43 It doesn't stress me out. And I kind of measure it sometimes with HRV and heart rate variability and things like that, and I'm like, wow, I do feel that we sometimes forget about the stress components. So that's if people really wanna dive into it, but I, but I agree with the message, which is anything's better than nothing, and it's probably not that much for most people, right? That's gonna give them some benefits.

Dr. Tommy Wood 1:28:04 Yeah. Uh, the main thing that I try and get across is that the dose needed or the amount you do needed to, to see some benefit, again, for, for most people is really quite low, and that... The... 'Cause, 'cause often what you see, and that's, that's kind of i- elu- what I alluded to earlier, is that people assume that they need some vast amount, several hours a week, in order to see benefit, and if, and if they can't do that, then they just don't bother doing anything.

Dr. Rangan Chatterjee 1:28:37 Exactly.

Dr. Tommy Wood 1:28:38 So the, the most important thing is to do more than you're currently doing, again, if you're relatively sedentary or you're, you know, trying to improve your health through physical activity. Um, and then, you know, once, once you get beyond that point and you have several hours a week to train, of course, there's lots of different protocols and different things that you can follow, but up until that point, you know, anything that you can do and is sustainable and you enjoy is gonna be great.

Dr. Rangan Chatterjee 1:29:02 You've touched on muscle mass, uh, through the lens of resistance training and how important that is as we get older. We have spoken about it before. One thing I wanted to cover though is, like, if I look at you, you're a muscly guy. You know, you like to... You know, you, you compete, I think, don't you, in-

Dr. Tommy Wood 1:29:20 Yeah, in Strongman.

Dr. Rangan Chatterjee 1:29:21 In Strongman, right? So that's a passion for you.

Dr. Tommy Wood 1:29:23 Mm.

Dr. Rangan Chatterjee 1:29:23 And you, you, you eat a certain way, you work out a certain way so you can compete in this sport. One thing I've been thinking a lot about over the last few months is what's the cost of muscle? Because I don't feel that we see often in these longevity hotspots really muscly people, right?

Dr. Tommy Wood 1:29:44 Mm.

Dr. Rangan Chatterjee 1:29:44 I haven't, I haven't gone out there and studied this in depth-

Dr. Tommy Wood 1:29:45 Yeah

Dr. Rangan Chatterjee 1:29:45 ... so I, you know, I, I can't say I know that for everyone or, you know, we often don't hear about them being really muscly in their 40s and 50s. And I often think about a place that I spent a lot of time in, which is Chamonix in France, where it's in the mountains, in the French Alps, and m- many people there, if not most people, are active.

Dr. Tommy Wood 1:30:04 Mm.

Dr. Rangan Chatterjee 1:30:04 They are, but very functionally active. So a lot of the time you'll see there people have got, uh, quite lean, um... They- they- they've, they've strong physiques, but not necessarily bodybuilding strong.

Dr. Tommy Wood 1:30:18 Yeah.

Dr. Rangan Chatterjee 1:30:19 Uh, you see this with mountain guys and, and I think a lot about, okay, there's a big movement now to say, "Guys, you've got to work on your muscle mass as you get older."

Dr. Tommy Wood 1:30:26 Mm.

Dr. Rangan Chatterjee 1:30:26 Because you're gonna lose muscle mass as you get older, and it's very important for longevity. It's important for brain health, as you've, you've covered, uh, before on the podcast. But we're not necessarily talking about big muscles, I don't think. I'd love you to expand on that and also, you know, I guess broad- broadly, you know, what is the cost of muscle mass? 'Cause the more muscle you have, I guess the more protein [laughs] and calories you need to feed that muscle. So how do, how do you think about that?

Dr. Tommy Wood 1:30:57 There's, there's several moving parts that, that I'll try and, I'll try and cover. The first is, is an important one, um, which you didn't ask about, but I will mention, which is that whenever I talk about muscle, everybody's like, "Well, I don't wanna look like you."

Dr. Rangan Chatterjee 1:31:11 [laughs]

Dr. Tommy Wood 1:31:11 "I don't wanna eat like you. I don't wanna train like you." And that is not what I'm saying. Absolutely not. Um, and when I say that p- that people should build muscle mass and strength, I'm absolutely not talking about what I do or other, you know, other people do in terms of bodybuilding or s- or strength training. Um, that's completely separate. I don't think that that's detrimental to health, and we'll cover that as well, but that's not what I'm recommending to people.

Dr. Rangan Chatterjee 1:31:33 Mm-hmm.

Dr. Tommy Wood 1:31:34 Um, a- and, and it's funny because I actually... You mentioned Gabrielle Lyon. And, um, I heard, uh, like, a-an anecdote, which is that somebody, uh, somebody was telling me that they'd been telling their ... or suggesting to their wife that they should, um, may-maybe do some strength training, you know, for all the reasons that we talked about, and it was sort of like in one ear and out the other. Um, but as soon as she heard another woman like her talk about the importance of strength training, immediately that-

Dr. Rangan Chatterjee 1:32:03 Mm

Dr. Tommy Wood 1:32:03 ... that, that message went in. So it's ... So the message is important, but the messenger is important as well, so-

Dr. Rangan Chatterjee 1:32:08 100%

Dr. Tommy Wood 1:32:08 ... sometimes it's not good for me to talk about muscle because people are like, "Well, I don't want... You know, that ... I, I don't wanna look like that." And that's obv- that's definitely not what I'm suggesting. Um, when you look at, again, so at the population level, we're gonna use that word again. So we do these large, large studies of people who sort of represent the population, and they've done it in the UK with the UK Biobank. They do it wi- in the, in the US with NHANES. And oth- I, I mentioned earlier how terrible the NHANES dietary data is. The other data they collect in NHANES is actually very good. Um, and what you see is that those who are in the top 50% of muscle mass, so, you know, just above average, they tend to live longer, um, and have a, you know, an overall lower risk of most diseases and, and mortality. But there's not, like, a dose response. It's not like more is better.

Dr. Rangan Chatterjee 1:33:01 Mm-hmm.

Dr. Tommy Wood 1:33:02 It's just don't ... So, so really the, the ... What you see from those studies is that low muscle mass being... And, you know, and we might use the phrase sarcopenia. That's the technical term for just having low muscle mass.

Dr. Rangan Chatterjee 1:33:14 Mm.

Dr. Tommy Wood 1:33:14 Um, dynapenia is related to low strength, um, or loss of strength. So low muscle mass is, is problematic, um, rather than more muscle being better, if that makes sense.

Dr. Rangan Chatterjee 1:33:24 Mm.

Dr. Tommy Wood 1:33:25 So you really just don't want to have not very much muscle. Like, that's where the real, um, signal of benefit comes from, again, at the population level. When, you know, studies that I've done either... And there's one we published just recently, and there's some other stuff that we're working on. Um, what we've found is that more muscle is not better, um, above a, you know, above that low level. But if you do have more muscle, it needs to be functional, so you need to have strength proportional to that amount of muscle mass. Um, and that's the kind of muscle mass that you generate through resistance training. So if I have more muscle, but I'm stronger with it, I think that that is just fine, right? That... But there's another scenario where you can gain a lot of muscle, and that's ... This is muscle measured on a, on a, like a DEXA scan, which is a type of X-ray scan. You look at how much muscle people have. And when they do that at the population level, those who have the most muscle, particularly in men, there's a, a p- a study that came out, um, from the UK Biobank recently. Those who had the h- the men who had the most muscle, the top, uh, it was either 20 or 25%, they had a higher risk of mortality and a higher risk of cardiovascular disease. But the men who were the strongest had the lowest risk. So there's this dissociation. That's another fancy word. Like, the separation of, like, strength and muscle.

Dr. Rangan Chatterjee 1:34:49 Mm.

Dr. Tommy Wood 1:34:50 So strength is what's important relative to muscle mass. And when I've looked at some of these data myself, those... You know, muscle does not correlate with physical activity. So these people are not gaining muscle because they g- they're in the gym all the time. They're gaining muscle because they're eating beyond their caloric needs and gaining more total mass, and some of... and, and with that, they, they tend to have worse metabolic health, um, more, you know, uh, high blood pressure, worse blood sugar. Um, so they, they're not... It's not muscle that's gained through lifting weights, right? It's muscle gained just through gaining more mass, and some of that is muscle tissue.

Dr. Rangan Chatterjee 1:35:30 So as people put on excess weight, there's an assumption that will always be fat.

Dr. Tommy Wood 1:35:36 No, some of it is muscle.

Dr. Rangan Chatterjee 1:35:37 So you still put on extra muscle as well.

Dr. Tommy Wood 1:35:39 Yeah. Yeah.

Dr. Rangan Chatterjee 1:35:39 Wow. And actually, that relationship between strength and muscle reminds me of conversations I used to have with a really good mate of mine who I was at uni with who was a, um, a very keen indoor climber, and he used to talk about the perfect... You know, they'd measured the perfect ratio between strength and muscle for climbers.

Dr. Tommy Wood 1:35:59 Yeah.

Dr. Rangan Chatterjee 1:35:59 Because you don't want too much because then you're too heavy.

Dr. Tommy Wood 1:36:01 Yeah.

Dr. Rangan Chatterjee 1:36:01 Like-

Dr. Tommy Wood 1:36:01 Particularly in the legs. Yeah.

Dr. Rangan Chatterjee 1:36:02 Exactly.

Dr. Tommy Wood 1:36:03 Yeah.

Dr. Rangan Chatterjee 1:36:03 And I was like... So it reminds me of those conversations.

Dr. Tommy Wood 1:36:06 Yeah. And I, I think the... So there are, there are two parts to this. One is that there are, there are these studies, and you talked about the cost of muscle. There are these studies that suggest that more muscle is, is detrimental, but that's because muscle, you know, muscle is coming along for the ride with, um, you know, gaining excess weight and worse metabolic health and all that stuff that comes with it. That muscle has not been gained with a proportional improvement in strength or function. But if you look at having a high level of strength or function relative to your muscle mass, that's incredibly predictive of cognitive function and, and mortality risk. So you want enough muscle. You just don't, you don't wanna have very little, and you want that muscle to be strong and functional. That's the most important thing, and that's, that's what you're talking about in terms of those, those individuals that you see, um, i- in the French Alps and in terms of the, the individuals you see in, in longevity centers or, you know, you know, places around the world where people live a long time.

Dr. Rangan Chatterjee 1:37:01 It's functional.

Dr. Tommy Wood 1:37:01 It's functional. Um, so whatever muscle that you have has to be functional. I think that's the main, that's the main takeaway.

Dr. Rangan Chatterjee 1:37:08 To make sure you're taking action after watching this video, I've created a free guide to help you build healthy habits. We can all make short-term change, but can those changes become a fundamental part of our life? Often, they don't, and that's why in this free guide I share with you the six crucial steps you need to take that are really, really effective. If you want to get hold of that free guide right now, all you have to do is click the link in the description box below. Now, related to that, Tommy Again, when- whenever we talk about anything, we have to think about in what population are we talking about it for.

Dr. Tommy Wood 1:37:49 Mm.

Dr. Rangan Chatterjee 1:37:50 And sometimes when I think about some of the protein research and the encouragement to high protein diets, I know we've covered that there's no real detrimental effects, and you th- you believe in, as I do, that many people are undereating protein. And we think about it in terms of our muscle mass. Like, if you're not eating enough protein ... Let's say you sh- let's say you should be eating 30 grams for your, for y- for your size at a meal. Now, let's say you get really, really active and do loads of strength training. If you do that, yes, I know you need protein to support the muscle growth. But is there a case to say ... And I, I kinda think that maybe this happens in some longevity hotspots, that they are really, really active, maybe not eating high protein, but because they're so active and they're so functionally active, they're still maintaining muscle.

Dr. Tommy Wood 1:38:42 Yeah. When you ... I think the, the best way to understand it in terms of the, say, the research that we have, is if you have individuals who are, um, calorie restricted, um, and when you restrict calories, one of the thing, right, you lose weight, and that comes from fat and muscle and, you know, o- other tissue as well. But in that scenario, if you add in physical activity, you preferentially keep that muscle tissue-

Dr. Rangan Chatterjee 1:39:14 Mm-hmm

Dr. Tommy Wood 1:39:15 ... and you'll, you'll preferentially get your, your energy elsewhere. So even if, you know, you have a, a, a period of time where you're e- either dramatically undereating or you have a, a high energy expenditure, um, then you will preferentially keep your muscle mass and strength as long as you maintain activity levels. So that becomes important if people decide to do long periods of fasting, maintaining activity is important so that you preferentially keep ... You don't l- use your muscle tissue for energy. Um, and so that's, that's partly what, uh-

Dr. Rangan Chatterjee 1:39:47 Mm

Dr. Tommy Wood 1:39:48 ... part of what comes in there. But I think there's, there's also been a big debate in terms of ... So, again, we go back, go back to the, the blue, the blue zones. There's, there's been some, some pretty reasoned debate in terms of how much protein those, those, um, groups are actually eating, and it is, it is probably more than the typical, uh, Western diet. You know, they're, they're not eating low protein diets. Uh, but then they're also physically active and all these other things that are important as well.

Dr. Rangan Chatterjee 1:40:14 I do remember, um, a conversation a few years ago. I was, I was speaking at a longevity conference, and Michel Poulain was there, who was one of the original researchers who went to study in the blue zones.

Dr. Tommy Wood 1:40:29 Mm.

Dr. Rangan Chatterjee 1:40:29 And he shared with me that, essentially, that in some blue zones they're eating more animal products-

Dr. Tommy Wood 1:40:37 Yeah

Dr. Rangan Chatterjee 1:40:37 ... than maybe-

Dr. Tommy Wood 1:40:39 Than we've been led to believe.

Dr. Rangan Chatterjee 1:40:41 Yeah. I love a lot of the stuff on blue zones for sure. I think that they're really, really interesting, but what their diet is, I, I, I'm not sure we're fully sure yet. [laughs]

Dr. Tommy Wood 1:40:51 Yeah.

Dr. Rangan Chatterjee 1:40:51 Or certainly I've heard conflicting things.

Dr. Tommy Wood 1:40:53 Yeah.

Dr. Rangan Chatterjee 1:40:53 Let's put it like that.

Dr. Tommy Wood 1:40:54 Yeah. And when you step outside of those, um, you know, small pockets, and you look at your more, say, uh, higher income or, you know, you know, Westernized, for want of a better word, societies, there are lots of populations around the world that eat a very high protein intake relatively and have some of the, the, the longest lived people on average. So, like Hong Kong and Iceland-

Dr. Rangan Chatterjee 1:41:23 Mm-hmm

Dr. Tommy Wood 1:41:23 ... eat a lot of animal products, a lot of meat, a lot of protein, and they are some of the longest lived nations on Earth. Um, so, so I think that using ... You know, the blue zones are informative, but if you try and look at an overall population that's closer to, to ours in terms of overall technological, you know, development or, you know, and access to foods, then those, I, I think are worth considering as well. Um, and in general, you know, they, there are, there are several that, that have a high protein diet and, and, you know, live a long time.

Dr. Rangan Chatterjee 1:41:58 Yeah, and I think also the nature of science often is to be reductive so we can measure one thing.

Dr. Tommy Wood 1:42:03 Yeah.

Dr. Rangan Chatterjee 1:42:04 But our human experience isn't that reductive, right? We have all different kinds of inputs into our lives. And so I often feel that it, it c- it gets hard because, you know, science is very useful to inform us, but then ... And, and I'm, I guess I'm biased from my experiences with patients where I kind of feel, yeah, that's one factor, but it kind of depends what are the other factors that are going on as well.

Dr. Tommy Wood 1:42:29 Yeah.

Dr. Rangan Chatterjee 1:42:29 That influences how much that factor is important.

Dr. Tommy Wood 1:42:32 Yeah.

Dr. Rangan Chatterjee 1:42:32 So thinking about food intake without also thinking about physical activity and stress and sleep, yes, can be useful, but potentially limited as well. So I, I-

Dr. Tommy Wood 1:42:44 I feel, I feel like we over focus on diet most of the time.

Dr. Rangan Chatterjee 1:42:47 So do I.

Dr. Tommy Wood 1:42:47 Like, that's, that's where everybody wants to go when all the other things that you mentioned probably for the vast majority of people are gonna be at least if not more important.

Dr. Rangan Chatterjee 1:42:55 Yeah. I, I totally agree. I mean, you've covered quite a lot, Tommy. I mean, maybe just one more topic.

Dr. Tommy Wood 1:43:00 [laughs]

Dr. Rangan Chatterjee 1:43:00 Um, supplements. [laughs]

Dr. Tommy Wood 1:43:03 [laughs]

Dr. Rangan Chatterjee 1:43:05 Um, you're a fan of creatine, aren't you?

Dr. Tommy Wood 1:43:07 Yeah.

Dr. Rangan Chatterjee 1:43:08 Why?

Dr. Tommy Wood 1:43:08 [laughs] Um, because it does everything. No, it's, it's probably the one supplement that I would routinely recommend to pretty much everybody. Um, there was a- There was a recent study that came out in, uh, post-menopausal women where they took creatine, um, for two years, and it, it was ap- associated with some improvements in, in, uh, bone strength. You know, obviously that's, um, uh, that's, that's, that's important for, for post-menopausal women. Um, I've... I'm a, I'm a big fan of it because of its effect on the brain. So, um, there are several studies showing that creatine supplementation acutely improves cognitive performance. Uh, that's in like in athletes, in young healthy people, and there have been large meta-analysis looking at creatine supplementation on cognitive function and, uh, the benefits are greater as you get older. So in those who are older, um, they, they have... they seem to have a great... they have a greater benefit. Um, there are studies where they've used creatine as an add-on to, uh, antidepressant therapy in those with major depressive disorder and seen a significant improvement above, uh, what, what they got in terms of the response from, from the antidepressant. And there are some, some studies suggesting that, uh, you know, the population level epidemiology, the amount of creatine that people get from their diets is associated with their, um, with their mood or risk of, um, mood disorders. Um, then there's the effect on strength that, you know, that in the majority of people, uh, creatine intake is associated with im- improved strength and, and, and muscle function. Um, so a wide variety of, um, uh, systems and organs in the body seem to benefit from, from adequate, uh, creatine intake. And not, um, it... The, the, the amount that you would take is, is maybe around something like 5 to 10 grams per day, and that's not, um, that's not a heroic dose, we'll go back to that term, uh, relative to what you could get from the diet. So a, a tin of sardines, um, is somewhere around 3 to 5 grams of creatine. So, uh, and, uh, 5 grams of creatine is probably, you know, it's like a kilo or two of salmon or, or beef. And like, and not a lot of people eat that much salmon or beef, but it's, it's possible to, to eat that much from the diet, but just most people don't. Um-

Dr. Rangan Chatterjee 1:45:29 What is it?

Dr. Tommy Wood 1:45:30 So it's, uh, um... It, it, it's, it's made out of three amino acids, and it's essentially... Well, it does, it does a number of things, but it, its main, uh, role is as, uh, an energy buffer. So earlier we talked about ATP, adenosine triphosphate, and when you move energy around the cell and you use it to do different functions with, with proteins and things like that, um, you do this in... with what we call high energy phosphates. So you break this bond with, with this phosphate molecule, and then that provides the energy for the process. When you, um, take ATP and you use up a phosphate, you create energy, uh, ADP, adenosine diphosphate. So it's gone from tri, which means three, to di, which means two. And then that needs to be recycled, and that's essentially what your mitochondria do. They're, they're recycling-

Dr. Rangan Chatterjee 1:46:33 Mm

Dr. Tommy Wood 1:46:33 ... ATP or generating ATP. Uh, creatine creates a buffer for that system. So creatine, you put a phospho- a phosphate onto it. It's called phosphocreatine, and it's used to recycle, uh, ATP. Um, so it, it's kind of like this short term energy buffer. Um, and that's why it improves, um, physical performance. But some of the things that it improves in terms of cognitive performance, we're probably less sure about. Uh, you know, it seems to have some effect on, uh, mitochondrial function and, and some other things. Um, it, uh, it integrates with the methylation system because, uh, producing creatine, w- and we make our own, um, is one of the most methylation intensive processes in the body. You know, by some accounts, the majority of methylation is used in order to generate and regenerate creatine in the body. So, you know, and then when you do that, you, you... if you supplement with it, so you don't need to make it yourself, then you're offsetting the need for B vitamins and-

Dr. Rangan Chatterjee 1:47:34 Mm

Dr. Tommy Wood 1:47:34 ... all these other c- these other, uh, nutrient requirements-

Dr. Rangan Chatterjee 1:47:36 Right

Dr. Tommy Wood 1:47:36 ... you know, as part of the system. So there's a number of different ways that it... And to be honest, we don't really know all of them. We, we know it has these beneficial effects that we've tested in randomized controlled trials, but the exact mechanism by which that happens is still kind of up for debate.

Dr. Rangan Chatterjee 1:47:50 Quite cheap and accessible for people, is it?

Dr. Tommy Wood 1:47:53 Uh, very cheap. Um, you, you know, if people are gonna, are gonna buy it, they should buy something called, uh, creatine monohydrate. That's the, that's the cheap form that's been, um, well studied, uh, i- in all kinds of populations for decades and decades. It's very safe. Um, most of it is made, uh, in Germany. Uh, it's a product called Creapure, and then they do what they call white labeling. So, uh, a sport supplement company-

Dr. Rangan Chatterjee 1:48:19 Mm

Dr. Tommy Wood 1:48:20 ... just like buy, buys it in bulk and then puts their own label on it. It's the same thing. So just like a s- a scoop of one of those. And it can also be, um, useful. If you're gonna buy supplements, in general, there's some due diligence that I would alw- always recommend that people do. So, um, there are third party testing companies or, or groups that test for impurities and that can be important if you're a, a drug tested athlete, but also for other things that you don't necessarily want to be in your supplements. So things like Informed Sport, you can see that as a stamp, uh, on your supplements. Um, and then often companies will say that they're batch tested or third party tested. That means that they're making sure they're not full of heavy metals and these other things.

Dr. Rangan Chatterjee 1:49:02 Mm.

Dr. Tommy Wood 1:49:02 Um, because, you know, some supplements, you know, particularly cheaper ones or you don't know where they, where they came from, they're made in some anonymous factory somewhere and who knows what's in them and, you know, wouldn't recommend that people take those. So you can, you can often ask for certificates of analysis so h- you know-

Dr. Rangan Chatterjee 1:49:19 Yeah

Dr. Tommy Wood 1:49:19 ... where people have tested for impurities and stuff like that. And I, I think that if people are gonna take supplements, it's worth doing that little bit of due diligence. But in general, if you see Informed Sport or something else, and like you can go to Holland & Barrett and you can buy an Informed Sport certified creatine monohydrate, uh, it's very cheap. You know, anybody can do that, and you don't need to spend a whole bunch of time doing research on it.

Dr. Rangan Chatterjee 1:49:38 Uh, and I think that brings up a, a wider point on supplements. And I think one of the reasons why the medical profession for many years has been quite anti-supplements is because of the lack of regulation.

Dr. Tommy Wood 1:49:50 Yeah.

Dr. Rangan Chatterjee 1:49:50 So there are poor quality supplements-

Dr. Tommy Wood 1:49:52 Yeah

Dr. Rangan Chatterjee 1:49:53 ... out there for sure, but there are also high quality ones.

Dr. Tommy Wood 1:49:55 Uh-huh. Yeah.

Dr. Rangan Chatterjee 1:49:55 And I kind of feel the whole thing, supplements good or bad, is a, is a ridiculous question in and of itself. It's like, are pharmaceutical drugs good or bad? Well, kind of depends-

Dr. Tommy Wood 1:50:06 Yeah

Dr. Rangan Chatterjee 1:50:06 ... f- for who-

Dr. Tommy Wood 1:50:07 Yeah

Dr. Rangan Chatterjee 1:50:07 ... in what dose.

Dr. Tommy Wood 1:50:08 Yeah.

Dr. Rangan Chatterjee 1:50:09 Uh, h- for how long for. And I personally have seen the right supplements be very beneficial for patients over a number of years. Um, so I have a slight... I don't really share that view that's been there in medicine for a number of years, which is, you know, we sh- you know, stay away from supplements. Because we routinely give them, like, B12 as a supplement [laughs]

Dr. Tommy Wood 1:50:31 Yeah

Dr. Rangan Chatterjee 1:50:31 ... or vitamin D as a supplement.

Dr. Tommy Wood 1:50:32 Yeah.

Dr. Rangan Chatterjee 1:50:32 And we, you know, so I, I don't kind of... Yeah. But, but there, there's a bit of nuance there, and as you say, if you're gonna get one, get a high quality one.

Dr. Tommy Wood 1:50:39 Yeah. And in terms of other, other supplements, in general, um, the, the vitamins be- like, come very, like, and those who need them come very high on a list of things that I would recommend. So, um, vitamin D, uh, very important. Some of the B vitamins, very important. Some, um, I think we measured, uh, talked previously about measuring something like a homocysteine-

Dr. Rangan Chatterjee 1:51:02 Mm-hmm

Dr. Tommy Wood 1:51:02 ... if you can, particularly if you're thinking about, uh, both brain health but then also cardiovascular health. And B vitamins that are relevant for that are RB12, folate, B6, uh, B2, which is riboflavin. And you can, you can get these from a, right, if you're eating, uh, some green leafy vegetables and, um, some eggs and meat, you'll get a lot of those.

Dr. Rangan Chatterjee 1:51:24 Mm-hmm.

Dr. Tommy Wood 1:51:24 Um, but equally, we know that being deficient in those is associated with a whole host of chronic health conditions. So, you know, I think we should, you know, at, uh, in terms of within the NHS, we should probably do, be doing a little bit more testing for those things so that they can be, they can be supplemented if, if needed.

Dr. Rangan Chatterjee 1:51:41 Yeah. Homocysteine I still think isn't routinely available-

Dr. Tommy Wood 1:51:44 No

Dr. Rangan Chatterjee 1:51:44 ... in the NHS. It's still a serum B12 and, um, you know, this whole thing about promoting diet and lifestyle first, yes, of course, but we also acknowledge in this conversation how tricky it can be for people to eat well.

Dr. Tommy Wood 1:51:58 Yeah.

Dr. Rangan Chatterjee 1:51:58 And that's why, yeah, I'm all for a food first approach, but at the same time, I recognize that many stroke most people are finding it hard [laughs]

Dr. Tommy Wood 1:52:08 Yeah

Dr. Rangan Chatterjee 1:52:08 ... to get the nutrition they need. There's, I don't know if you've seen this research on soil quality and how that's poorer now, and so are we getting the same level of nutrients that we were getting 50 years ago-

Dr. Tommy Wood 1:52:18 Yeah

Dr. Rangan Chatterjee 1:52:18 ... from the same foods? That's really interesting. Also, I've tested, um, B12 a number of ways over a period of years, and I've been really quite surprised by how many people have suboptimal B12 levels.

Dr. Tommy Wood 1:52:34 Yeah.

Dr. Rangan Chatterjee 1:52:34 Even animal food eaters. And I think a lot of that may also come down to the chronic stress in society, 'cause we need good stomach acid to absorb B12 if it's going through our gut and into our stomach, and one of the things that chronic stress will do is alter levels of stomach acid, alter how your digestive function is. And so I'm thinking, well, I think, uh, more people than we currently think, I think, would probably benefit from-

Dr. Tommy Wood 1:52:59 Yeah

Dr. Rangan Chatterjee 1:52:59 ... improving their B vitamins.

Dr. Tommy Wood 1:53:01 Um, for B12 also, like, if you're taking a proton pump inhibitor for reflux, or if you're taking metformin for types of diabetes, like, both of those can also, partic- for B12, precipitate, um, a B12 deficiency. So there's a lot of other things that we're doing. We're m- managing these other health conditions where we could then be making a, a, a B12 deficiency or insufficiency worse. So, so that, that's a critical one, but then all the B vitamins, um, I th- you know, I think we, we've become focused on B12 and folate, but-

Dr. Rangan Chatterjee 1:53:28 All of them

Dr. Tommy Wood 1:53:28 ... these other ones become important as well, yeah.

Dr. Rangan Chatterjee 1:53:30 And I will say that if you are low, I, the amount of patients I've seen who've had vague symptoms, really low energy, and then, you know, in one patient I pres- remember in particular, checked their homocysteine, it was through the roof, you correct it, they just feel like a different person.

Dr. Tommy Wood 1:53:46 Yeah.

Dr. Rangan Chatterjee 1:53:47 And they can go for years not getting properly treated and having a substandard quality of life. And so, yeah, a lot more we could talk about.

Dr. Tommy Wood 1:53:56 [laughs]

Dr. Rangan Chatterjee 1:53:57 Hey, Tommy, I think we've covered... I, I think we've done pretty well.

Dr. Tommy Wood 1:53:59 Uh-huh.

Dr. Rangan Chatterjee 1:53:59 Well, you've done great on a-

Dr. Tommy Wood 1:54:00 [laughs]

Dr. Rangan Chatterjee 1:54:00 ... on a whole host of different topics. Anything on those topics that you feel you didn't say that you want to get out there?

Dr. Tommy Wood 1:54:05 No, I, I, I don't, I don't think so. I, I mean, for each of them you could, you could spend an hour and do a lot of, a lot more homework, um, to, to really delve into all the nuances. But the important thing, I think, to remember is that none of these things are good or bad, and context is always important, and, you know, just understanding how these things might be im- important, uh, for you. But then, but then hopefully also when people have gotten conflicting messages, we've, we've kind of helped them navigate maybe where they need to enter into something or, or whether something is worthwhile for them.

Dr. Rangan Chatterjee 1:54:42 Yeah. Well, Tommy, I really enjoyed that. I really hope the audience like what was a very different format to these normal conversations. And if they do, we can perhaps do another one and cover another 8 to 10 topics. But thanks for coming back on the show. I appreciate it.

Dr. Tommy Wood 1:54:56 Thanks so much for having me. This was a lot of fun.

Dr. Rangan Chatterjee 1:54:57 [upbeat music] If that conversation resonated with you, here is another incredibly powerful one that I really think you're going to enjoy.

Speaker 1:55:04 If at 37 your limit is just being able to run that 30-minute park run, at 75 you're gonna have a very difficult time getting around