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60% of people in this country are either overweight or have obesity. One in four people. A lot is the answer. Hello and welcome to Instant Genius, a byite-size masterclass in podcast form. I'm Jason Goodger, commissioning editor at BBC Science Focus. In today's episode, we're speaking to Professor Jio about the biggest myths surrounding weight loss. So, Professor Josio, welcome to the podcast. Thank you so much for having me, Jason. You're very welcome. So today we're going to be talking all about weight loss. So many people watching will likely want to drop a few kilos if possible. So what's the current situation in the UK with our weight overall? So do you know what? 60% of people in this country are either
overweight or have obesity. 60%. And if you just look at the obesity numbers, one in four people have obesity. just slightly behind the United States, which is roughly one in three people with obesity. A lot is the answer. So, we're all different shapes and sizes due to many things like our genes, our lifestyles, etc. But how do we actually classify someone as being overweight? Overweight or obese? So, so that's a that's an interesting question. I think there are two ways of looking at it. There is just a pure weight thing. Now, if you're looking at just a weight, then we tend to not just use weight because
obviously people come in different heights and what have you, but something called BMI, body mass index, which is your weight in kilograms divided by your height in meters squared. So, if you use that particular metric, then being overweight, well, being normal weight, quote unquote, is having a BMI between 20 and 25. Um, being overweight is between 25 and 30, and having obesity is above 30. So those are the numbers of just pure weight. The issue obviously is that doesn't take into account fat versus lean mass. It doesn't take into account any number of different things. And I think more a more sophisticated dare I say nuance definition I think of overweight or obesity is carrying too much fat that it
begins to influence your health. So that was a very long answer but I felt that it was probably needed just to get some nmanllete kind of sorted. Yeah. So, do you think sort of um body fat percentage is a better measure of this? Body fat percentage probably is a better me uh um measure, but then on top of the complexity of that, where you put your fat is also important. So, I think you probably want to do body fat percentage plus your waist to hip ratio. So, the circumference of your waist over the circumference of your hip. And that then tells you sort of your body shape. And so and so where you're putting the fat that I think is the most useful piece of information. So what are the boundaries of that ratio then?
Do you know what the boundaries or the ratio would differ between uh um between different people? But put simply, if famously apples-shaped people, sort of people who tend to have larger tummies and more likely are men than women, although not exclusively, will have a higher chance of metabolic disease of being ill for a given weight. People who are pear-shaped, so those are people who have bigger bums but smaller tums, um who tend to be women but not exclusively, tend to be healthier. So what happens there is if your waist to hip ratio is higher, then you are going to be uh um at more metabolic risk. If it's lower, then you're going to be at less metabolic risk, put simply. So let's look into
something that you've written about like you wrote a book, Why Calories Don't Count. So a lot of people when they're thinking about food and diet, the first thing they'll go to is calories. So what is a calorie? So a calorie is a unit of energy. It was originally um I mean it was actually in invented to calculate the amount of heat given off when dynamite went off. Like seriously, that was the gunpowder went off. So it was used to measure by the French the Napoleonic times. Okay. to try maybe slightly later to try and measure well when it when something went boom. Okay, how much boom was it? And so the calorie was actually used for that um initially then people began to actually
begin to use the whole concept of the calorie within agriculture. They were beginning to use it in food and they wanted to know, oh, okay, well, if we fed, you know, cows or chickens or whatever, you know, x calories of food and then what came out the other side, they were trying to get sort of like use using it as a um how efficient were animals at converting food into a product. Okay. And then laterally it is now been moved from animal sort of food to then human food. So that's the sort of the history of the calorie and how it ended up being sort of labeled on the side of a pack of food. Yeah. So we have them on packets of food. But not all calories are equal. There's something called uh
caloric availability. So can you explain that for us? The caloric availability is the amount is the amount of calories you can extract from a food versus the total amount of calories stuck in the food. I'll give you an example. So if you had sugar, okay, like table sugar, sucrose, so one molecule of fructose, one molecule of glucose, and if you had 100 calories of that, you get pretty close to 100 calories, probably 98 calories or so, because it just needs one cut and we absorb it. Okay? And so that means that sugar is probably 98% calorically available. So that's probably one extreme. Now if we deal with the other extreme, sweet corn, corn on the cob.
Now if you had 100 calories of sweet corn and you were and then you looked in the L the next day, it would be pretty clear you have absorbed nowhere close to 100 calories of sweet corn. But yet if you actually take corn and then you uh you desiccate it, you turn it into a masa and then make a corn totilla, you make you make a cornbread, whatever, suddenly a far greater percentage of those calories are made available because of the processing of that corn. But yet it's corn. And so that is why where the calories come from really matters because we eat I guess the bottom line is we eat food and then our body has to work to extract the calories and depending on what you're eating your body has to work more or
less hard to extract the calories. So you often hear people talking about something called empty calories. You know nutritionally useless foods or drinks or substances. What do they mean by that? I don't like the term empty calories. I don't think it's a real thing because I think most food that we eat will have some nutrients in them or some nutritional value, some more than others, I guess. Um I think what people however and what the public consider empty calories are foods that are calorically high but nutritionally low. Um, in shortand for nutritionally high, you talking about nutritional density. This tends to be either protein, fiber, uh, um, micronutrients, vitamins, you know, and iron that kind of stuff. And if you can you
can have a food that is high calorically, like you eating just purely sugar for example, but low in everything else. There's no protein and obviously in sugar, there's no fiber, there's nothing else in it. Um, so that is an example of a empty calorie, quote unquote. It clearly isn't empty but I think that is what the term means. It means high caloric high calorie food low nutrition density. So you mentioned there protein. So um we eat protein, carbohydrates, fats but we process them differently don't they? Don't we? Sorry. So can you explain that? You know what happens in our bodies? So, so these are called macronutrients and we'll take the two easiest macronutrients for our body to process and those are going to be fat
and carbs. Now, fat and carbs are made exclusively from three atoms uh carbon, hydrogen and oxygen but sort of in different configurations. So therefore our body has an easier time to sort of deal with it because when you eat food you there's only two things you can do with food. You either store the food or you burn the food. That's it. You can't magic it out. You can't sweat it out. you can't detox yourself, right? Those are the two options. And so if you only have those three atoms, they're easier to deal with. The problem with protein is primarily formed of carbon, hydrogen, and oxygen, but also a lot of nitrogen. So about 16% on average, depending on what we're talking about, of protein is going to be
nitrogen. Now because you either use it or burn it if you h sorry you either use it or store it. If you actually have to store uh protein there is no inert store of protein in our body. There is for sugar which is glycogen. There is for fat it's fat. There isn't for protein. All the protein in our body is active. Okay. It's either there for this. It's there for repair. And if you eat too much it has to be stored as fat. But if it's going to be stored as fat, then nitrogen needs to be taken out. There's this is a lot of words, but it's also a lot of energy. And so for every hund and you wee out the nitrogen as ura uric acid, that's this is what come up. Okay, this one makes your we smells like weed.
And what happens is for every 100 calories of protein, imagine if you ate 100 pure calories of protein, only 70 calories are usable to us. 30 calories is given off as heat um as energy just to kind of sort the protein out. Um you might one wonder what the other macronutrients then do. Well, fat, which everyone is always the most interested in um sadly is pretty close to 100%. Because fat is nutritionally dense, very calorically dense. And so 100 calories of fat is 100 calories of fat. Um sugar 98. Now carbohydrates, complex carbohydrates, now it depends whether we're talking about something with fibers, a whole meal or without. So if you actually take a look at just white
bread or white past, you know, like refined pasta, okay, then we're probably looking at 95% available. So 5% of the calories from starchy uh white starches are going to be uh used to sort of sort it out. Um 95% available. Whereas if you eat something whole meal, if you have whole meal bread, if you have quinoa, if you if you have anything with the husk on, then suddenly you increase that you decrease the availability to 90%. So it takes about 10% of the calories in order to sort it out. Incident, so calories on a whole are about 5 to 10% wrong, quote unquote, because everything I just told you, none of it is reflected on the side of the package of food. So, so the calories that are there are just the calories in
the food and they do not reflect the amount of energy the cost of business. It does not reflect the amount of energy it takes to actually uh process and metabolize and actually sort out the macronutrients. So it kind of like the overarching message of that is not all cos are equal. So then they are once they are in you as a little poof of energy but in the presence of food as you are kind of sorting out your food your meal and digestion and metabolism there's not equal. So the moment it's metabolized in your mitochondria and ready to go they're equal but there's so many steps to there and that's why they're not equal. So lots of people go on calorie controlled diets and um you know is that a good idea? It is if you're doing it well okay
it is if you're doing it in a balanced fashion. So say for example you have actually quite a balanced diet. You just eat too much of a balanced diet and hence you have obesity or overweight. Um, and if you are then doing a calorie counting diet by saying that, well, normally I have whatever 2,000 or 2,500 calories a day. I'm now going to eat exactly what I eat, but I'm now going to cut it by 20%. Yes, then it will work. But that's not how we work, right? Because if suddenly someone says in some diet, oh you have to limit your lunch today to 400 calories say okay um you go and you might look at the back of the pack and suddenly says oh look at this chocolate bar is only 400 calories.
I know this is a slightly ridiculous example but clearly there's a difference between having 400 calories of a salad or yogurt or a chocolate bar. So that is I think where the calorie counting falls down. So if you can do it in a balanced way and that is why a big reason why these um energy replacement shakes are popular because they are nutritionally balanced. They typically come they typically come in 400 calorie sort of uh um serving sizes and so you may have two if you're trying to do a low calorie typically is 800 calories a day for whatever reason. And so you have two of these shakes, one for lunch, one for dinner. And that's fine. Of course, you're going to lose weight and you're
going to lose it relatively okay, right? In terms of that, but a lot of people just blindly count the calories without considering the nutritional content of the fruit they're eating. And that is the issue. So, what can the consequences of that be? You know, if I'm thinking, well, I want to eat for 800 calories a day and I'm just having a fizzy drink and a chocolate bar. What's going to happen to me? Well, you need enough. You need enough of everything. This is the problem, right? And so how much is enough? How much is enough is depends on it depends on what you're doing. But ultimately we do need balance because we
need fat and we need carbohydrates. But most importantly and those two are very easy to come by in most foods. Okay. But most importantly we need protein. And the reason why we need to eat enough protein back to a point I made earlier is we do not store protein. Our protein is there for repair, for growth, u for use. And so we need to eat enough protein to make sure we can continue to do that because fat within ourselves anyway, obviously everything ends up as fat at some point as storage. So the problem with having a poor quality diet and this is why it's useful to use protein as a shorthand. Okay, you can have too much protein but it's useful as a shorthand because that is
the one nutrient we need to eat and we need to eat enough of. So the problem with having a fizzy drink, it has got no protein in it at all. That is where the problem will come down to protein. So what happens if I have too much protein? Um the gym bros hate me when I say this because you can't have too much. you can have too much protein and they're saying, "Well, I have, you know, whatever some so and so, whatever, however they count it, but they're lifting or an Olympic athlete or a professional athlete, they are damaging their muscles through using it so much. They need a buttload of protein." Now, mere mortals like us, you don't need no protein shake. Like, seriously. So, the problem with having too much protein when you're not using
it is you have to store it, right? which means that there's all the process of having to deal with the nitrogen. So you put stress actually on your kidneys and probably also your liver. Not because these are toxic, but because you have to process it. It's got to get into it's got to get from your blood into your wei, you know, and if you suddenly have a lot of nitrogen coming through the system more than you might naturally have if you were having a balanced diet, you put stress on your organs that sort out uh um extracting the nitrogen from your body. That's the primary reason. So, let's have a look at another popular thing now, which is fasting. Yep.
Especially uh intermittent fasting. So, you know, what's the idea behind that? and you know does it work for weight loss? Okay. So there are a whole emporium of these intermittent fastings and this can be intermittent in the famous 52. So where for 5 days in a given week you eat normally and 2 days you fast or eat very low calories. But it also now includes what we call timerestricted feeding. And so some people instead the 16 uh 168 for example where I only eat between noon and 8:00 p.m. every day or something. Okay. So that there is a period of the 24-hour period of the day where you don't actually eat the principle. So first of all, they tend to be quite effective as a weight loss tool. They are effective um because they're a
useful strategy to get you to eat less. So you do end up with a energy or caloric uh um deficit. Hence you end up losing weight. Um the question to ask is whether or not there is any additional metabolic benefits beyond simply the fact that you've eaten less. Um it's surprisingly difficult to answer. I mean from animal studies because obviously that's controlled. You can do this you can that I think there is a subtle metabolic benefit a benefit to it. humans. It's very difficult to do dietary studies in humans because the gold standard for any kind of study is a randomized control trial, okay? And blind it if possible. The problem with a diet is you can't randomize it. You
certainly can't blind it, okay? Because you're either fasting or you're not. And so it tends to be observational. Um but I wouldn't be surprised if there was a subtle metabolic benefit. The underlying principles are this. If you fast either for a longer period of time of a couple of days or if you make sure that between that you only eat during a certain period of the day, the store of energy that goes the quickest is glycogen. So glycogen this is where you store your carbohydrates. We don't have a great we don't store a great deal of carbohydrates in our body. We store 100 to 150,000 calories worth of fat in our body because that's our primary energy stores. We only keep about two to two and a half thousand calories of
carbohydrates in our body largely within our liver and muscles and a little bit floating around our blood as glucose. We burn through that pretty quickly because carbohydrates are the easiest to get ATP from. They're not very dense, but they're very responsive. So, we tend to go through that first. And so what happens is when you do fasting, you sort of get through a lot of your glycogen stores getting your body to try and go into burning to burning fat. So therefore producing ketones. Okay? So ultimately that's what happens. If you burn carbohydrates, you don't produce ketones. If you burn fat, you produce ketones. This the principle of the keto diet. It's the principle of the fasting diet. Same things because you go
through your glycogen, you produce ketones. ketones naturally make you feel fuller. Sorry, that was another very long answer, but that ultimately it is there is an overlap between the fasting approaches and something like keto because you force your body or at least you encourage your body to burn more fat producing ketones. That's the underlying principle. So coming off the back of that, let's talk about exercise. So a lot of people that want to drop a few kilos, they think, well, you know, the best way to do that is, yeah, I'll exercise. You know how does that work? Well, the exercise that just be crystal clear here. We don't want to give the wrong message. There is nothing better for you in the whole damn world than
exercise. If you could bottle it, we should bottle it. Okay? It's good for your mental health. It's good for your physical. It's good for everything except weight loss. And that's that's the irony. And it's one of these things where and whenever I say this, people think I'm anti-physics. I am not anti-physics. Clearly if you take it to if you look at elite athletes particularly endurance long um particularly endurance uh long-distance athlete moah you know the tofront cyclists so clearly they can exercise enough to lose weight and eat like a horse okay they eat whatever 5 10,000 calories a day in order to do it most of us are not doing that and so what we tend to do is two problems is when we first of all when we exercise we do obviously burn through calories,
but we get hungry. Anyone who's done any level of exercise will know, maybe not immediately after, depending on what you're doing, but at the end of the day, you go, "Oh, I'm famished. I could actually eat." And we tend to sort of under overestimate, pardon me, how many calories we burnt during exercise. These garment things tell you or what have you. And you think, "Woo, I exercise today. I can eat this. I can guilt-free have this muffin or what have you." And you end up eating more than you need. So exercise is actually not particularly good at all for everything else. It is not good for weight loss. It is however good for weight maintenance. So once you've lost the weight, which you need to tackle the
food intake for and you've reached some plateau or some target weight you want to do, then actually exercise is quite a useful way to help maintain it because as you lose weight, the smaller you become, the lower your metabolic rate is. This is the weird thing, right? And it's not weird. A Mini will always have a lower a few lower fuel use than a Range Rover. That's always the case. So, as you lose weight, your metabolism drops trying to bring yourself back up to the weight you were before. So, exercise, when you exercise, your energy expenditure, your metabolism goes up temporarily. So, when you're exercising, you're obviously using ATP, you're giving off heat, you're doing all the
things, and then when you stop, it then comes back down again. So once you're actually reaching reached your target weight, then you can increase your physical activity. Doesn't have to be going to the gym, gardening, walking your dog, whatever. Okay? And during that stage, you are temporarily raising your metabolic rate and sort of mitigating against your brain, dragging your body weight back up to what it was before. So let's have a look at appetite then. So this is really, you know, something that seems like thrown around everywhere. It's actually more complicated than you'd think. like uh do people sometimes really have bigger appetites than others? Uh yes they do. So appetite is an interesting um term.
It's quite a complex term because it's an integrative term. It integrates at least I'll go at least sort of three concepts feelings within us. So it includes hunger. We understand what hunger is. It includes how full you feel. Completely different circuit completely different part of the brain. hungry and fullness. And it includes how nice you feel when you eat. The reward pathways of the brain. They're like a triangle with, you know, of all three bits with appetite in the middle. And you can change how nice you feel about the food, how full are you, and how hungry you are because they all speak to each other. And so appetite sits in the middle. And so ultimately if we look at the genetics
of this why some people feel more hungry or have a higher appetite than others. It can be because of any three reasons and they're not mutually exclusive. Some people feel more hungry. Some people um take more food to get filled up. Some people have a some people need to eat more to get that same high from food quote unquote. Okay. M um but all of us have a mix of that. And so ultimately if you have a higher appetite for any one of those three reasons, you end up finding it more difficult to say no to food than others. And so why some people are larger than us others? So how about sort of um you know mental conditions such as stress because you hear people
saying that they're stress eaters. Um, and I think like some people are stress not starvers but you know they their appetite plummets when they're stressed. So do we know anything about that? So I mean you can probably divide the world into two broadly for people who stress eat or you can even use the term emotionally. So in other words they're stressed and so therefore they eat in order to try and mitigate against the unpleasantness of being stressed and people who lose their appetite when they're stressed. I mean my wife is the latter. So the moment she's you got to distinguish incidentally between tiger stress and everyone reacts to tiger stress in exactly the same way. Run like hell you're not interested in food. Okay. So
that's the so that's that is an acute stress the fight or flight you now we're talking chronic stress work stress exam stress that's kind of stress and then you have this interesting it's the same hormone cortisol goes up my wife says ah no appetite okay I won't eat you know whereas I do eat when I get stressed and my bowl my response tends to be you know putting my face into a bowl of noodles for example um why mechanistically we don't actually know. Okay. However, I think the sort of the reason it happens mechanistically we don't know is being stressed is unpleasant and as all living creatures do if we are feeling unpleasant we want to remove that unpleasant feeling and so we use
different strategies to sort of feel pleasant. I mean, for some people that's eating. Eating to a lot of people is pleasant. And so, you eat in order to try and feel pleasant to counteract that unpleasantness of being stressed. Other people use drugs of abuse. Other people drink. Other people go run marathons. Other people bungee jump, right? And so, and so I think there are different ways of making yourself feel more pleasant in a stressful situation. Um, and some people do it with food. the mechanisms, neurons, the circuits, still not known. So, let's let's move on to something else then, which is age. Um, I don't think you'll mind me saying we're both middle-aged. We are. Um, and uh, you know, there's this term middle-aged
spreadshe is that a real thing or is it just an excuse? So you know this is a more complex question to answer um than you might actually imagine because I think I would probably have given you a different answer if you'd asked me 5 years ago actually. So let me give you the wrong not the wrong answer the less right answer first and I think the less right answer is that we are uh born and then we have very high metabolic rates then we hit 18 you know that's probably our peak okay and then it sort of stays and then around the what we call middle age 40 to 50 suddenly it begins to dip and drop and that used to be the explanation for one of the explanations for middle-aged had now some guy uh a colleague of mine actually John Speakman
so he's based out Aberdine and also he has a lab in Beijing um where he's shown that actually for any given amount of muscle you have lean mass okay because that primarily drives your metabolic rate um actually you don't drop metabolic rate till you reach your mid60s and older okay so he's done he's he's done the sum so this is new this is actually new relatively new science. Why do we get this middle-aged bread? I think for a number of different reasons. So, first of all, on average, the older you get, the richer you get, not so rich, but you begin to accumulate uh either wealth, um stuff, you do different jobs. You tend to be sat on your backside more in your job.
You do get a tapering off of physical activity as you get older. That it's just on average, that's the situation. As a result, you begin to lose muscle mass. Okay? And as a result of that, your metabolic rate drops, but not if you divide it by the muscle that you actually have already. Do you see what I'm saying? So you're losing muscle mass and hence your absolute metabolic rate is dropping, but not per gram of muscle that you actually have. Problem number one, and I think that's a that's probably the key driver. The second key driver is less biological, but what happens is you get richer as you get older. You buy better food, you buy richer food, you eat in different
places, and then and what happens is you probably end up eating a bit more. And you mix that with the fact that you are more sedentary because of your job, because you're older, your muscle mass uh um dropping, and I think that is the explanation for middle-aged bread. Now clearly that um trajectory is going to differ between you and me and someone else. It's going to differ between a male and a female and it's going to differ between ethnicities. But as a concept I think that's the reason why. So let's have a look at a new phenomenon then which is these weight loss jabs. Okay. So you know what are they? Do they work? Are they safe? Okay. Excellent question. So I mean I think the
most famous one is Ompic. Um but others are available now Monjaro. Um and what all of these new class of drugs are modified versions of naturally produced gut hormones. So your brain needs to know broadly speaking two pieces of information to influence your food intake. It needs to know how much fat you have. Um and it needs to know that because that's your those are your long-term energy stores. Okay? how long you'd last without food. So, it needs to know that um hormonal um but it also needs to know what you're currently eating and what you have just eaten. Okay? Short-term energy stores. And these are going to come from your gut, your stomach and your gut. And all of
these signals are hormonal. And so, two of these hormones are something called GLP1 and JIP GIP. And both of these go up after you eat. Okay? They're natural hormones. These are now not the drugs. They're natural hormones. Now these drugs sorry these natural hormones GLP-1 and JIP are called incrretins and they're called incrretins because they enhance the secretion of insulin for every given gram of food that you might actually eat. Okay. So that's why they're that's why they're called incrretins and that's why these drugs which are based on them were originally diabetes drugs. The second thing which they do is they signal to the brain to make you feel full and that's why
they're used as obesity drugs. The magic power of these uh of what the pharm pharmaceutical companies have done is they have sort of decorated molecularly decorated these naturally uh um hormones this natural hormones to keep them in the blood for longer because the halflife of the natural home of the halfife of GLP1 as it goes up is 2 minutes. So typically it's designed to do this. Okay, as you eat it does this whatever and then there is an enzyme in your body called DPP4. It doesn't matter but it sort of chops it up. So as if you inject yourself with native hormones it's not a good drug at all because what happens is it just gets destroyed. So these drugs have been are modified versions of these hormones
that now obviously I mean originally they were once daily injections but now with Ompic Monaro they have now become once weekly injections and actually there are other ones coming down the line from other companies which are going to be ones monthly injections and so because of the way they have molecularly changed the molecule it's still the hormone GLP1 or JIP but because of the molecular uh modifications they stick around the blood for longer therefore helping with diabetes and helping with obesity. So is there any danger to using these? Do we know d Okay. So dangers is uh danger probably yes and no. So let's let's let's go with that. So u the class of drugs actually incrretin class of drugs as we call them
have been in use for two decades. First as the ones for actually first as twice daily then once weekly and so they've been around for a while and we would have thought and millions of people have therefore been on them that if the class in of itself is dangerous we would have seen them dangerous in terms of as a toxic or addictive or something like that. None of this is true. There are however side effects um when you're actually on these drugs and they tend to involve the gastrointestinal tract right your gut because that's where the hormones are come from. So these drugs broadly speaking these hormones broadly speaking the gut hormones help to regulate the flow of food through the tube the food to poop
tube right speed um and any and anything else. So for example, if you had a bad prawn, okay, and had food poisoning and then you ran to the L explosively, what happens there is because gut hormones in particularly GLP1 has spiked. It really go and you go, okay, it comes out the other side. Hence the most common side effects of these drugs is nausea because you can imagine I know people who are slightly more pukey than others. You know, ah I feel puky. Um so if you are more sensitive to the drugs then you may very well feel nausea when you actually take it. The other problem is the other end okay it also regulates the right speed or it can be sometimes too fast or sometimes too slow the other end. Okay.
And so hence those are the other two common side effects either diarrhea or constipation depending on where you sit on the distribution of speed of flow. And so those are the common side relatively common side effects but the vast majority of people who started the trials of these drugs completed the trials. So it can't have been that bad and I guess more and more people are now taking them. So are they dangerous? They're dangerous because they're powerful and they'll work for pretty much anybody. They'll work for a 350lb man looking to lose 100 lb and that's great. They'll also work for a 16-y old girl who's 75 pounds and that's not
good. Okay. And so these are drugs. I think they should be used as a drug which means that it should be used to treat obesity and the associated conditions because you are ill. I do not think they should be used as a cosmetic tool. And I think ultimately why do we want to lose weight? There are cosmetic reasons I'm sure. But I think these drugs should be used to treat the illness and so that's why they're dangerous because there is no if you're this weight they suddenly won't work. So by way of summary then say somebody does who's watching does want to lose a couple of kilos um what's the best way to go about it you know the healthiest way in moderation is the real answer.
Let me get because I think that I if I had a really good answer, I wouldn't be here talking to you. No, it's not true. I think ulti I think this is the real the answer is you have to find a way that suits you. So I think each everyone is okay different strokes, different folks type of thing, but it's true. Okay. So I think most people say that 95% of diets don't work and that's not true. 95% of diets you can't stick to. That's the problem. All right. Uh, now the drugs have come in and have they are very useful because they remove the hunger aspect of it, which means that you can stick to whatever it is you're doing a lot easier. But leaving aside the drugs just for two seconds. If you're doing it in a behavioral perspective, you want to get
on a diet, you want to do something, then you can't just do the diet and stop because what happens is the weight will just come flooding back in again. Um so you need to if you want to do it using by changing your diet then you need to change your diet and find something moderate because by definition if you pick something extreme you won't stick to it. So moderate mo moderately now they're clear like me my wife thinks I should lose a stone and a half she's right don't judge me and no one's going to give me a drug but they're going to be situations actually where you are either very ill for a given weight or really have quite severe obesity for any number of different reasons and there that is when the drugs
and at the most severe end probably surgery comes in but that's very extreme But that's where the drugs come in. So I think how you do if you want to lose a couple of kilos the likelihood is behavior will probably sort of help but then you need to come up with a strategy to try and stick to it. If you need to lose 10 kilos, okay, which is obviously a lot of weight, there may be the uh something like a drug with in conjunction uh with a diet because remember these drugs just make you feel full. They'll make you eat less of whatever it was you were eating. Okay? So, in other words, if you were eating chips and Oreos, then all it'll do is make you eat less chips and Oreos. And so, hence, that's not a
healthy diet. So you do need to also have a to also have a healthy diet. And so there is a spectrum. The more severe your obesity and or illness then I think you need to go away from simply trying behavior because otherwise behavior would have worked previously you know to maybe having some pharmaceutical help. Great. So thanks very much for this conversation Charles. Um it's been a pleasure speaking to you. Thank you very much for having me. Thank you for watching this episode of Instant Genius brought to you from the team behind BBC Science Focus. That was Professor Joles Yo. To discover more
about the topics we've just discussed, check out his book, Why Calories Don't Count. If you like what you just watched, then please do like and subscribe.
