Ultra-processed foods, weight-loss jabs and why don’t we eat enough fibre?
Professor Brian Cox takes a deeper dive into the science of nutrition with a panel of returning experts answering more of your questions.
What is food noise, the impact of artificial sweeteners on the gut and why do many women turn from a pear to an apple shape during menopause?
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More Questions of Science gives you extra episodes that continue the conversations started in A Question of Science.
From his home studio, Professor Brian Cox catches up with expert panellists from earlier in the series. Together, they tackle your follow-up questions, explore new angles and go deeper into the topics that sparked your curiosity.
Brian: Hello, and welcome to this bonus episode of A Question of Science, the show where we tackle your questions on everything from Artificial Intelligence to the future of fertility with the help of a panel of leading experts. The original debates were recorded in front of an audience at the Francis Crick Institute in London, and today's episode is a chance to answer some extra questions that we didn't have time for. The debate on whether we can trust the science of nutrition revealed that the British diet is suboptimal.
As well as learning that only 7% of us get enough fibre, it was also clear that food environment really influences our unhealthy food choices. So let's pick up the conversation where we left off with Professor Giles Yeo Cambridge University who studies the genetics of body weight. And Nita Forouhi, Professor of Population Health and Nutrition, also at Cambridge University.
Thanks both for coming back. Now we had a huge response to the debates, which even caught the interest of the committee responsible for drawing up the government's national food strategy. So these discussions are having an impact. And Giles, since we last spoke, there's been some major research published on the effects of ultra-processed foods on health, so let's start there. I know you're skeptical of the term ultra-processed foods, but what did this study actually find?
Giles: This was a series of papers actually that were published within The Lancet. And the first of those three, was trying to associate increased consumption of these ultra-processed foods with a number of different diseases and conditions.
And in effect, what the study said was that if you have more ultra-processed foods, you increase risk of, pretty much every disease known to man and including increasing chances of death. So all of these are very grim reading, but my key point about this is that what is an ultra-processed foods still matters.
Because if within the whole concept of ultra-processed foods, you have a whole lot of foods that are not great for us, okay? But then other foods that are technically ultra-processed foods but are fine for us, then if you do some kind of population-based studies, then you're gonna find that these foods that are bad for us, are bad for us, but it's still sorts of encompassing other foods that are technically ultra-processed that are perfectly fine for us.
Brian: We, we had a comment actually from Martin about ultra-processed foods. He said when he listened to the debate, he said he thought that the focus was on levels of fat, sugar, and salt.But is it that the real problem is they, in his words, contain stuff we may not consider to be food where he says there, it's made in the lab. So it's quite a sort of a complex area, isn't it? What, what is the ingredient? I suppose that's what you're saying, Giles, what are the ingredients that are causing problems?
Giles: From my reading and my looking at the evidence, it is largely down to levels of fat, sugar, salt, protein, fibre, you know, actual nutritional content of the foods, and some mixture of that, that is not going to be great for us. There may be some role to play in terms of mouth feel and texture, but it's not like people are adding crack to the food, you know, to make it suddenly more addictive or anything like that.
Brian: It's not defined, is it? 'Stuff we may not consider to be food'? I'm not sure what that is. If you eat it, I suppose by definition it's food. Nita? Right.
Nita: So. You know, the definition of ultra-processed foods was first put forward in 2009, so not that long ago in research terms. We have come a long way in trying to understand them now. It's absolutely correct that the ultra-processed foods' harm - or the badness - doesn't come solely from the fact that they're high in saturated fat, salt, and sugar. But there are studies that control for, well, what happens if we look at the association between UPFs intake and all these different health conditions adjusting for these nutrient intakes, there is still a residual and significant association.
So what are these other factors? And as you know, Martin has raised rightly the question, is it these extra additives? Now, the definition of UPFs was precisely based on that. It originally said and has maintained that it is not so much solely about the nutrients, but these additives. What are they?
They're preservatives, emulsifiers, gums, sweeteners, colourings, stabilizers, all of these. They add up, and actually there is research now, at least from one group in France that have been very active in this. They have published a number of papers in some really very good scientific journals where they have studied different types of preservatives and sweeteners and emulsifiers, and found that they are associated with all of those same health effects. So what I would go back to is these individually are fine, because there are safety regulations and we say, well, they're allowed to be added in the food and that's why they're there.
So they're not toxins in their own right. But the argument is that those are individual, assessed individually, but when you put them all together in a cocktail of different types all in the same thing, that's where you get overburdened and that's where the ill-effects come in. And there's just one other point that's worth bearing in mind. I think the word 'foods' is a bit misleading because overall I would argue that when people eat or don't eat largely ultra-processed foods, it's about the overall dietary pattern that they're eating within. So let's take an example. When you have the Mediterranean diet, we talk about the entire dietary pattern, and we say people who follow that sort of pattern and culture, they have all these health benefits versus those who don't follow it. We then don't break it down into aha, but in the Mediterranean diet, these 15 components, this one is good, and this one, you know, is it this one or is it that one?
It's about the overall pattern. So I think that's how we should think about ultra-processed foods.
Brian: It's quite difficult as a consumer, isn't it? Because when you look at food that you buy, the labeling you see is, you know, saturated fats and calories and those things. It, it's quite difficult to discern, isn't it?
How many of these other stabilizers, as you say, artificial sweeteners are in there? I suppose it is in the labeling somewhere, but if someone was concerned, then what would they look for if they were looking at a particular product?
Nita: Yeah, so there isn't a regulatory requirement to name every single additive, but essentially look for whether there's artificial sweeteners, those would be usually listed and E numbers. Those are a good starting point. And, and, flavourings and extracts will also be listed. Typically, things that you wouldn't have in a sort of normal kitchen or a household. Things that you wouldn't be looking in your kitchen cupboards and then you say, oh, what's this?
I don't understand what this is. So those are the sorts of things to look for on the label.
Brian: But just to be clear, I suppose from what you said, we don't know whether there's any problem with those, those things either. I mean, you, you're not giving advice to avoid those kind of ingredients, are you? We don't know.
Nita: So, no, I wouldn't say we don't know, but I think we are halfway there. So the glimmerings of research evidence in terms of association studies have already come forward. But now we need replication by scientists in different populations and in different countries, and we need to firm up that evidence because the way dietary guidelines and government recommendations are made is not on the basis of, oh, well there were two studies from one country that showed this.
What happens is you take the full sort of body of evidence and then you say, well, what was the quality of that evidence? Were there trials? Were they observational studies? You put it all together. So, definitely there are research studies that have raised the association. Now for one thing, there is a bit more evidence in terms of which of these additives, and that is on the artificial sweeteners, there is research that shows, you know, impacts on, for example, the gut microbiome of artificial sweeteners not being great.
The World Health Organization did a very comprehensive review of artificial sweeteners and they did stick their neck out and say artificial sweetens are not helpful for prevention of chronic diseases, they should not be taken with that in mind.
Brian: Giles, did you have anything to add?
Giles: These are not products that we've had in our more traditional foods, and I guess I would always just think about why these foods were there to begin with.
I don't think they were designed to try and kill people. I think they're designed to try and feed eight billion people in the world. So we need to constantly look at the food chain and, and how we're actually putting products out there. But these products have a long shelf life, easy to transport are cheaper.
They are consumed by people who are in a lower socioeconomic status. That is an issue, and I think we just need to do more research. I would, I guess, counsel about using these foods that are typically consumed by people who are less privileged as a way of food shaming them, shall we say. I do think we need to keep our eyes open with the science and look, if the science tells us that these foods are less good for us or not great for us, then we need to take steps to actually remove them from the food chain.
Nita: Yeah. I think what we need going forward is convenience foods that are healthier. That's the challenge.
Brian: Yeah. Thank you. There, there's a, actually a related question in terms of at least a consumer trying to assess what they're eating on, which is a question about labeling from Jason Davis. People often say calories in, calories out as a metric for healthy weight management.
He asks, but is this simplistic? Because calorie labels differ from different brands of the same food and different people absorb calories differently. So I suppose the first question, Giles, is, how does calorie absorption work?
Giles: It's as simple as calories in, calories out once the calorie is within you as a little poof of energy.
Because the calories after all, is a unit of heat, right? We eat food, we don't eat calories, I guess is my point. And then your body works harder, or less hard to extract the calories, but once it's in your mitochondria as a little poof and it's converted to ATP, they're all the same. It's physics. The problem is different foods have different caloric availabilities, which means that the calories are more or less easily extracted from the foods.
My problem with the calorie is when you actually consider it in the food, that it is one dimensional. So the calorie tells you how much energy there is that is actually there, stuck in a food, how much food you're eating, but that's it. It's nutrient blind. It doesn't tell you fat, sugar, salt, fibre, protein.
And so I think the calorie gives you one piece of information, but you need the context around that specific calorie, what that calorie is based in, what type of food are you actually eating?
Nita: That's absolutely right, and I very strongly have come to the conclusion that not all calories are the same, precisely for the reasons Giles you've raised.
And by way of example, if Giles and I, let's say if our body size was the same and we were equally physically active and we both consumed, let's say 2,000 calories. And I consumed french fries and drank sodas and basically had no fibre in my diet, whereas Giles being the good one here, he might have lots of lovely whole foods, fruits and vegetables, fibre rich oats, and all sorts of things.
So those 2,000 calories will not have the same impact in the body because there are mechanisms through which satiety and hunger signals are also affected by those, how we respond to glucose and the spikes we get from eating food, in our glucose, those are affected and a whole plethora of other things, including the effect on the gut microbiome and so on.
So the body is such a dynamic system. There are lots of physiological things going on in there. So within that, a calorie is not just a calorie in that sense.
Brian: So, yes, Jason's point is, the answer is yes. Is calories in calories out too simplistic? The answer is. Yes it is. Yeah, it's too
Nita: simplistic.
Giles: I was gonna say is that whenever we do say that it is too simplistic, then there are a whole sector of society that think we're anti-physics and we need to just to stress that when we say that a calorie is not a calorie, even though it is a unit of heat, that we are not being anti-physics.
We're just talking about a more complex system.
Brian: I absolutely concur with that. We can't encourage that kind of behaviour.
Nita: Speaking to a physicist here.
Brian: There's actually a related question again about where you are getting your energy, where you're getting your nutrients from Sabine Rohde-Patterson, who wanted to know what happens if you do away with food altogether. She asked: what is the effect on our health, physically, mentally using food replacement drinks?
So how long should they, be used for if they are considered safe?
Nita: So food replacement drinks have been used very successfully in some of our best evidence for say, the remission of type two diabetes and for weight loss. And you know, we have the NHS soups and shakes diet, for example, which is effectively a meal replacement.
They are massively effective in creating what we call a calorie deficit. So you could go down to 800 calories per day. The challenge is for how long? And the answer there is, short term is best. So typically in these clinical trials, it would be for eight to 12, a maximum of 20 weeks that people would go on this.
And there are many benefits to keeping it short because, you know, we don't eat food just to live as it were. Food is about fun and enjoyment and family and friends and all of that. So being able to eat food at a table with your friends and family is very different to having a sort of meal replacement drink which should be part of a short helping period.
So outside of people trying to lose weight, let's say, sometimes it again boils down to convenience where people say, right, I'm just so busy, I haven't got the time to cook, and if I get takeaways, it won't be healthy food. So let me have these meal replacement drinks, as it were. But over time, just beware, again going back to that conversation about ultra-processed foods, a lot of them do have additives and preservatives or you know, sweeteners and so on that are added to make them palatable.
Giles: Giles? I agree because I think there's two elements, right? So is it fulfilling our nutritional requirements? Yes. Is it fulfilling the joy in our life?
I would argue no. There is a convenience aspect, but I think these are short term tools and I can see why these are used, longer term they're not gonna be sustainable.
And where's the joy in life if you're drinking your calories from a shake, would be my view. Yeah.
Brian: One of the key topics in, in the original discussion was fibre, and the message that overwhelming majority of us don't get enough of it, but there's a question from a listener who wanted to know why we need it.
So the listener said, no one gave a reason why it's so important, so we could cover that. But then to an individual with, irritable bowel syndrome, for example, fibre is pain.
So, is it necessary for them? So maybe Nita, you could start with why is it so important and there are people for whom if you just increase it, then it can cause problems.
Nita: So fibre's usually important. It's been neglected, but there are at least four reasons and more why it's so important for health. Firstly, it's all around gut health. Now, most people know that when you don't eat enough fibre, you get constipated. So that's a really good reason to have more fibre. But actually there's a lot more going on in the gut other than only the constipation or diarrhea or normal bowel movement.
There's also your gut microbiome, which we now know is so important. There are billions of these bacteria in our gut, and fibre is a really good way to promote the healthy bacteria. A second reason beyond gut health is that fibre intake helps to lower cholesterol, particularly the bad cholesterol levels like the LDL.
It, it reduces the absorption. A third reason is when we eat food, we always get spikes of glucose. Over time, these spikes of glucose put a lot of pressure on the body, particularly the pancreas. We get insulin levels raised and ultimately the body kind of grumbles and, and people can get type two diabetes.
So fibre intake helps to blunt the response, the glucose spikes after eating food. And that's really, really important. And the fourth reason is we have done a lot of research in this area with large studies, as well as other research groups that have shown that higher fibre intake versus lower fibre intake is related with reduced risk of developing very serious health conditions later in life, such as colon cancer and cancer more broadly. The evidence for colon cancer is really strong between fibre and reduction of colon cancer, diabetes, heart disease, premature mortality. So people with IBS, it's a real issue. Definitely it can be very painful to have more fibre and, and you know, you get cramps, you can get diarrhea, flatulence, all of those.
However, fibre is still important for the body, for the reasons I outlined. So how do we get around it? Well, fibre is not just fibre. Fibre is of different types. There's insoluble and soluble fibre. And the way, doctors and dieticians help people is to initially go on what's called a low FODMAP map diet, in that you eliminate a whole host of foods that you reckon were making your IBS bad, and then you gently reintroduce things one at a time and then you work out, personalized to you and based on your genetics, which foods you will tolerate, which have fibre and which foods you won't, and have the right type of fibre.
So psyllium husk and so on can be, given as supplements for instance, but also avoid fruits and vegetables, that, that have skins where you get the sort of fibre that particularly flares up the IBS.
Brian: So if someone said, right, I want to increase my fibre, what are we talking about in the diet?
Nita: Fibre comes in plant-based foods. Forget animal source foods for those, so it'll be fruits and vegetables and legumes, which means beans and chickpeas and things like that. Nuts and seeds also have to some extent, a degree of fibre, but it's the cereals and whole grain cereals, which have really good types of fibre in them. And the reason I say whole grain cereals or whole grains is because there's a challenge here. If we have the very highly processed or refined variety of the same grains, then the fibre content is depleted out of those.
Brian: Giles?
Giles: It's interesting that Nita says it's a neglected nutrient because I think it wasn't considered a nutrient for a long time, right?
Because we don't actually absorb and get any calories from fibre, per se, which is always the interesting thing, and people have thought that in order for a nutrient, you need to actually extract some energy from it. So it's all the peripheral stuff that actually comes from fibre that makes it good.
And so when getting nowhere close to it. I mean in simple terms we're saying eat more fruits and vegetables and whole grains. That's broadly what we're saying about, about fibre. And that is probably one of the issues with ultraprocessed foods in addition, is that they're inherently low in fibre as well.
Brian: Mm. So it's difficult, but it's actually simple. If someone's listening, it's fruit, vegetables, whole grains. It's a simple message, but difficult to do as a consumer. Absolutely.
Giles: But why is it difficult as a consumer? I mean, this is always the thing, right? It's such a simple message and most of us know this, but yet it is so difficult to deploy this across the population.
And I think that's one of the interesting questions to ask why.
Nita: And part of that why is very much to do with what we call our food environment. You know, what's available, what's pushed at us, what is advertised. I haven't seen many adverts over at least the last 10 years that say, go and have more fibre.
All the adverts are around the colourful and tasty, salty, sugary, fatty foods because marketing makes a huge difference.
Brian: Well, thank you. We now have a question about GLP-1 weight loss injections. This is a question from Jenny Wilson who is a doctor and she wrote to say: As a GP I'm seeing increasing numbers of patients accessing weight loss injections.
What is the evidence for disproportionate muscle loss rather than fat loss and longer term effects of these injections, if and when perhaps weight is regained? So maybe
Giles, I know you've worked on this?
Giles: So when people lose weight, on average you lose around 60% fat, 40% lean mass, however you lose the weight.
There's obviously a little bit of a wobble around there, and there are a couple of different reasons for this, particularly rapid weight loss, the biggest one being that if you are now carting around less weight you need less muscle in order to move around that weight. And muscle is very expensive to maintain.
It just is, and humans are inherently very efficient creatures. So I don't think that there is any convincing evidence at any rate that this lean mass loss is anything other than rapid weight loss. And it's not specific to these GLP-1 based therapies, these incretin based therapies, okay. Now this may change as more and more millions of people have it, and we'll look at that. Now, there is evidence, however, particularly in mice - I mean, this is largely where, where the studies have been done - is if you lose weight on, say, a GLP-1 medication, and then you stop the medication and the weight comes back on, that there is a preferential gaining of fat compared to lean mass, this is true. But once again, I think that this phenomenon is based on the fact that it's easier to put on fat. Because fat after all is whatever spare nutrients we don't use and you kind of squash it into fat. That's what, that's what fat is for. Whereas it takes longer to actually build back up muscle again because muscle still requires some kind of resistance training, things like that.
So I think the lessons that we learn here are that if you rapidly lose weight, you will lose lean mass and if you then stop that when you come back up, fat will come back on first. This is true. So the only way to mitigate against this is to actually do exercise and physical activity and making sure that you, you maintain a high quality nutrient dense diet.
That means eating enough protein so that you sort of try and protect your muscle mass loss as much as possible.
Brian: Very interesting. What I'm hearing there is the injections are part of a change of lifestyle, so there are other things you should do alongside them, which are things you should do anyway, essentially. Get the diet right, get the exercise right, and use it as part of that process.
Giles: Correct. We need to push this message out more - which is why we do things like this - that you shouldn't use these drugs, and they are drugs, not cosmetic tools in isolation. You need to do it as part of a whole suite of behavioural changes, including your diet and including physical activity in order to maximize your health benefits that you're gonna get from using these drugs.
Brian: Nita?
Nita: I agree a hundred percent with what Giles has said, where my concern comes in is as a population health doctor, the data we have still is pretty short term. We simply don't have the long-term data yet and things may unfold. So what concerns me is that, you know, up to say between a quarter to 40% of the weight loss is lean or fat-free mass, some of which - possibly around half of that, let's say - is likely to be skeletal muscle. And there are some meta analysis that have come along that have looked at up to 2,000 or so people, let's say, from different trials where imaging studies were done. And by imaging studies, I mean, you know, they were able to look at the body fat compartments and they do corroborate or confirm that there is this lean mass loss.
So, longer term, we then go back to the same message that we should keep it simple. Don't use these drugs as a magic solution; protein intake in adequate amounts, but not protein intake alone without resistance training, strength training, and muscle building. Because particularly as we age, we tend to lose muscle.
And then if we are also on these drugs that make us lose weight, then there could be a double whammy effect of age, hormonal effects as well as these drugs. So those are really critical things. So
Brian: given that these tend to come through GPs, it was a GP that asked a question, Jenny asked the question, is there advice at the moment for GPs when prescribing these drugs to also be very clear that there should be an increase in resistance training, for example, if possible?
Although again, I know that's difficult for some people. Is it delivered at the moment as part of a package to patients?
Giles: It probably is via an NHS based system, but there were something like 2.6 million doses of, of these GLP-1 drugs that were prescribed last month, for example, okay. 95% of those were done privately, so the 5% that we're getting within the NHS at the moment will come because then you're going to your doctor, you're going to things, and there's a dietician there.
The 95% that are doing it privately well, where are you getting it from? Are you getting it from some less than scrupulous provider? Are you getting any advice at all or are you a rich person who can afford a nutritionist and a personal trainer? And so there is a huge unevenness in the amount of information we're getting because so many of us are getting it from the private sector.
Brian: Does that speak to, ultimately more regulation in the prescribing or the way that you get these or is that naive?
Nita: So I think that would be the ideal scenario, to have regulation and to have a standard protocol, which is in the same breath that you prescribe this for clinical need together with that this is a checklist: have you given the patient advice, information and support on these aspects of good nutrition and resistance and and strength training for muscle maintenance? That would be the dream, but we are quite far from it, and currently, in fact, it's an issue, which is probably increasing health inequalities rather than helping with them because of this private sector, the cost of these drugs and a certain amount of people who might need them, but because of the cost and because of the eligibility criteria on the NHS, they feel they need it but they don't qualify, they then don't get it.
Brian: We now have a question about how our environment shapes what we eat from Caroline Graham. And she asked: What is food noise? Where does it come from? Does it serve a purpose? Why do some people seem to have it dialed up to 11 and other people don't have it at all?
And is it genetic? So Caroline says that she takes a GLP-1 and the drug doesn't suppress her appetite, but has almost completely switched off the noise she lived with her all of her life, enabling her to make healthy choices about diet and therefore lose weight. So Nita, that this idea of food noise, I know we touched on it in the original debate.
Nita: Yeah. So food noise, first of all, what is it? It's a kind of constant humming, like a mental chatter about food. You can't stop thinking about food and it's exaggerated because of the food cues. And what are these food cues? Precisely what the listener has raised. It's our environment, which is flooded with very attractive looking foods out there, which are hyper-palatable, delicious.
There are reward systems in the brain that they make go ping, you know? So there, there's all this sort of attraction to that and you know, it's, it's sort of all-pervasive and you can't turn it off. But with the use of the weight loss therapy as described, these drugs work not only on the weight loss, but it's the mechanisms through which they work on the weight loss.
And there is, activity in the brain in terms of then switching off this very intrusive sort of food noise, which is there the whole time.
Brian: Giles?
Giles: First of all, I had never heard of the term food noise till these, the drugs are suddenly on the market. So it's been an interesting thing to try and unpick what it is.
And I just get the feeling that food noise means different things to different people. Food noise could be, I feel a bit hungry all the time, and so hence I always think about food, but then there's my kind of food noise. So I love food. I can raise my hand. I'm a food lover. I'm definitely not a food as fuel person.
I have an appetite, obviously. I eat my food and I feel full. Then I don't have to eat a great deal. But I think about food all the time. So this has always been an interesting thing for me where I am now full. So I'm not gonna want to eat anymore if you given me anymore food. But I still am thinking what am I gonna have for dinner tomorrow night?
What I'm gonna have to do is Chinese New Year, right, that's coming up soon. I already have the entire menu planned of what I'm gonna do. And so that is my food noise because when I talk to my wife, I mean she says, don't talk to me about food, I'm full. Whereas I can think about food. So that's another aspect of it, and I think it's a reflection of some internal hormonal state that is gonna differ between me, between Nita, between you, Brian, about how we actually think about food after we've eaten. It's our feeding behaviour and that is where I think the genetics comes in, right? Where people's reaction around food, how much you think about food after you've eaten. That is where the genes come in. They influence the noise we hear they influence why some people use food as fuel.
They influence why some people will eat when they're stressed and other people when they're not.
Brian: Thank you. We had a lot of questions on this topic actually. So Tricia Gill asked: Is it true that it's more difficult to lose weight if you are menopausal? And Tracy Sherwood Farmfield asked if it's true that trying to diet at this stage in life actually acts to raise cortisol levels, making it harder to lose weight by calorie deficit? So Nita?
Nita: The menopause definitely makes it easier to put on weight and harder to lose weight. Now let's distinguish it from what we all know as a phrase, which is middle age spread. Men and women are both prone to that because as we get older, our metabolism is slowed down a little bit, and on average, physical activity levels decrease.
And so going back. To our previous discussion about calories in calories out in this context, you are over consuming calories relative to expenditure in the menopause. There are hormonal shifts in women with oestrogen levels going down, and that makes a material difference. To the biology of how fat is metabolized and how fat is stored.
So it's easier to put on weight, but also it's easier to put on weight in the wrong places. That means fat, which is around your internal organs. We call it visceral fat because it's actually not something inert. A lot of people think, 'oh, well, you know, fat is just kind of like dead tissue is just something we just want to get rid of.'
Actually, it's a highly metabolically active tissue, this visceral fat. So that's what lower oestrogen levels, do they drive the shift in fat storage in the abdomen. Then the next question was about the stress of dieting. Does it raise cortisol levels? So, to my knowledge, this topic is not done and dusted or fully understood because, you know, it's quite a complex situation about how cortisol levels in the body are raised.
It's a sort of stress response of the body. We call it flight and fright reaction. So in the menopause, there are already stresses on the body based on the biology. So that already has a relationship with cortisol levels. For instance, hot flushes, sleep disturbances, those have a real impact on stress response in the body.
Now, dieting on top of that, again, it depends on the person on their genetics. For some people that will add extra cortisol, for others it won't. To simplify it, I would say yes, the menopause does make it harder, but because we know from clinical trials that weight loss is effective even in postmenopausal women.
And what's really interesting is that recently there was actually, interesting research which showed that in postmenopausal women, if you combine the GLP-1 weight loss drugs with hormone replacement therapy, the magnitude of weight loss was actually greater. Not massively greater, but a few percent greater.
Giles: I think the one thing I would add is that it's not just a drop in oestrogen, this is a thing, but actually the other relevant thing is the change in ratio between oestrogen and testosterone. So women have testosterone as well, obviously just far lower than men, and so there is an internal ratio between these male and female hormones, for lack of a better term.
And so everything that Nita was saying about the increased risk of, you know, visceral fat, increased risk of insulin resistance, normally affect men more, males more, and in large part because of this ratio between oestrogen and testosterone. So in the menopause, what actually has happened is your ratio becomes more.
Male, for lack of a better term. Hence, all this increases in diseases that you normally would see, in men.
Nita: And if I could add one thing, you know, we've been focusing on weight gain in this particular question, but in the menopause, because of these hormonal changes, women's relative protection that was there before the menopause compared to men is lost.
It's blunted. So risk of heart disease, for example, is typically lower in premenopausal women than age-matched men. But after the menopause in women, the risk begins to catch up. You know, to understand body fat distribution within the body. In easy terms, we talk about apple-shaped bodies and pear-shaped bodies. So premenopausally, when there is excess of fat intake or calorie intake, women deposit the fat more in their hips and thighs, and you know, therefore you end up with this sort of pear-shaped body, as it were. And men typically deposit it around their organs and the abdomen so they get like an apple-shaped body. But, postmenopausally women begin to move more towards the apple shape and all of that affects long-term health.
Brian: So that is why, for example, heart health, so it's the fat distribution is more male post menopause.
Giles: Correct. Then, then you end up with this stereotypical, I don't want to get women mad at me, but stereotypical boxy shaped, post-menopausal shape.
In some women. And that's because you're shifting where you're storing your fat into a less good place in your body.
Brian: Yeah. Well thank you very much. We've covered a lot of ground there, and that's all we've got time for. We should do another one of these actually, shouldn't we?
Because we had so many questions that will maybe you can come back Yes.
And carry on and we'll do another hour. But thank you for now, to Professor Giles Yeo and Professor Nita Forouhi for coming back and we'll be here again next week to answer more of your questions of science. Goodbye.
