The 5 ways early nutrition detemines your health for life with Prof Lucilla Poston

The blueprint for your life starts much earlier than you realise — long before you took your first breath, before your heart beat its first beat, before your mum and dad even met. 

This is the story of the first 1,000 days of life. From conception to age 2, a window so powerful that scientists now believe it influences our future risk of heart disease, obesity, diabetes, and even how our immune system reacts to the world.

In this episode, the world’s leading expert on how childhood nutrition and metabolism shape our long-term health, Prof. Lucilla Poston, explains how early nutrition may influence appetite, metabolism, and future disease risk. 

Lucilla offers practical guidance on what matters most and explains key nutrients to consider. They discuss why regular movement may help support healthy blood sugar levels. They also explain what a balanced diet can look like for parents and young children, why babies should try a wide range of whole foods, and why many packaged baby foods may contain far more sugar than parents expect.

What small choices can you make today to help shape a healthier future for you, your children, and your children’s children?

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Jonathan: Lucilla, thank you for joining me today.

Lucilla: My pleasure.

Jonathan: And Federica, wonderful to have you here.

Federica: Excited to be here.

Jonathan: So we always like to kick off this show with a rapid-fire Q&A, and we have these very strict rules for professors, Lucilla, which is you can say yes or no, or if you have to, you can give us a one-sentence answer. You willing to give it a go?

Lucilla: Yep.

Jonathan: Can obesity really begin in the womb?

Lucilla: In part, yes.

Jonathan: Can the father's lifestyle before conception influence a child's future health?

Federica: Yes.

Jonathan: Federica, during pregnancy, should the mother eat for two?

Federica: No.

Jonathan: Are baby pouches a good way to feed young children?

Federica: Not by themselves. No.

Jonathan: Lucilla, can what a mother eats before conception affect the health of a child as an adult?

Lucilla: Yes.

Federica: This episode isn't just for couples trying to conceive or for people who are already pregnant. This is for the population to understand that if we can be in good health before we're pregnant, it massively improves the health of the baby. And it improves maternal health because it reduces the risk of things like gestational diabetes or preeclampsia, which is high blood pressure in pregnancy and can be very dangerous. So this is the kind of podcast to send to your friends, your aunties, your sisters, your daughters. Because if you can get to a better, healthier diet before you are pregnant, that's where the magic really happens.

Jonathan: Alright, well look, I'm really excited to get into all of this and I'd like to start right at the beginning with Lucilla. What does this mean? The first thousand days of life.

Lucilla: Well, if you work out the days, it's the number of days in pregnancy plus the number of days up to the age of about two. So it's very important in pregnancy and postpartum that you think about nutrition, particularly during those thousand days. I personally think it's not long enough, so you should go back to preconception and then you should go a bit further down the line in terms of the age of children, maybe up to the age of five or beyond. But it's a good way of thinking about vulnerability in mums and babies.

Jonathan: I think the thing that surprises me is that it doesn't start at birth. You're talking about nutrition starting before they're even eating anything.

Lucilla: That's right. Well, they are eating something effectively through the placenta.

Jonathan: Can you help me to understand?

Lucilla: Yeah, so essentially the baby isn't eating itself. The baby is dependent on the mum for eating and what it needs, and then everything that the baby needs goes across the mum's placenta and then gets into the baby's blood and then the baby benefits from that or not, depending on what the mother's eating. The nuances of that are considerable. So, you know, there are lots of different things that we have to consider about whether the placenta is transporting those nutrients from the mum's blood to the baby's blood effectively, and which ones are getting across and which ones go across better than others. But essentially that's how it works. I mean, that's how a baby gets its nutrition, it is entirely from the mum, but the baby is essentially eating from the mother's blood and it's not through its mouth.

Jonathan: Why do you feel that this time period is especially important versus, I dunno, the thousand days from when I'm 10 to 13?

Lucilla: So if you think what's happening from conception up to the age of two is massively fast development. So the baby is an embryo, then the baby becomes a fetus and the baby becomes a bigger fetus, and then it becomes a child. And huge amounts of cell division, which means that the baby's growing. The cells of the brain, the cells of the nervous system, the cells of all the organs. What they're doing during that period is dividing rapidly so that the organ or the nervous system develops in size and complexity. When a division is happening, the baby is very vulnerable. So the fetus is vulnerable, the child is vulnerable, just the division of cells exposes the mothers and the babies to this problem. So this is why during that period you're vulnerable, because of the developing cells and the division that's going on all the time. And it carries on beyond the thousand days, which I'm saying maybe, you know, we need to think of it longer than the thousand days. But the fetus and the baby are particularly vulnerable because they're growing.

Federica: We call it the golden window of opportunity because as Lucilla said, Jonathan, every organ, every cell actually is built in that time period. Especially the first trimester is when almost all of the organs are set. By the age of three, children's brains are pretty much almost adult size. So it's a lot happening in those first three years of life.

Jonathan: Hang on. I just wanna say, so you say by the age of three, my brain is almost full size?

Lucilla: Well it gets bigger, but all the cells are there. The connections are made between the neurons, which are the cells in the brain—

Jonathan: They're just—

Lucilla: —not as well hooked up. Perhaps.

Jonathan: Most parents would like them to be.

Lucilla: Perhaps not. Well, they carry on until puberty and beyond, of course, but the more vulnerable period in development is up to that age. Yeah.

Jonathan: What you're saying is so much of a human being's development is actually happening just in that first a thousand days. And therefore, if anything doesn't go in the best possible way, it's likely to have a knock-on effect throughout the rest of your life.

Lucilla: If you take the kidney, for example. By the time a child is one, the kidney is fully developed in terms of its structure. The heart is the same, the number of cells in the heart is set by the time you're born. Pretty much. So you can see why it's important to get that division right and to get the growth right. Because if it's perturbed in any way, that can then last forever.

Jonathan: And I feel you've hinted at this, but I'd like just to make sure I understand it, which is things can go wrong through this period and that therefore what happens in those first thousand days can end up having an impact on your long-term health. Could you help us to understand that, Lucilla?

Lucilla: I think it's, well, think of a few examples and how this all started, actually. There was a guy called David Barker, who when I was first a young student, was sort of ridiculed for his ideas. Nobody believed him, but what he showed was that in the north of England, if people were born small, and you follow them up until they're older, they have more cardiovascular disease, they have more problems with their metabolism and cholesterol and so on. And he said, well, this is because they were born small, and nobody believed him. And they questioned his statistics. And I can remember him being ridiculed on a stage at a conference, you know, and it was called the Barker Hypothesis. And David Barker was an evangelist, if you like. He was really, really keen on this. But he was right. So if you then start looking in studies, in small animals and so on, you could see this, that when there's a small baby, they have a fewer complement of nephrons. Sometimes the kidneys are imperfectly formed, the hearts are not adequately mature. But in people, exactly the same thing happens as we've seen in rodents and everything else. We know that is absolutely a permanent change. During your life, you can modify the risk by eating well and being healthy. But if you have that initial problem, then you're more vulnerable to chronic diseases. I mean even cancer, but particularly metabolic diseases and cardiovascular diseases. That was the start of it. And I remember taking him to task and I said, well, the problem that we have, David, is not so many small babies because of undernutrition. We have an awful lot of large babies because of overnutrition, too much energy being taken in pregnancy. And he said, oh, no, no. He says, that's irrelevant. So I set out to prove him wrong, and I think we did prove him wrong because it happens the other way round as well. So if the baby is born too large, there seem to be longer-term consequences, particularly with obesity. And another example of some of the awful experiments of nature, if you like. At the end of the Second World War in 1944, in a reprisal against the allies helping the Netherlands, the Nazis imposed a siege on a lot of the big cities in Holland. The problem about the siege was that food supplies weren't getting into Amsterdam, for example. And then the clinicians in the hospitals carried on recording the weights of the babies, the weights of the placentas, and they followed and are still following up the children from what was called the Dutch Hunger Winter. And these children became adults who had a quite substantial increased risk of cardiovascular disease and increased risk of lung problems and so on. So that was one of these ghastly nature experiments, if you like. And that's been repeated again, the siege of Leningrad and a famine in China, showing that very poor nutrition in utero and being born underweight has long-term consequences for health. So that was really the beginning of the whole concept of the developmental origins of health and disease, which is what it's now called.

Federica: And I think what's fascinating about the Dutch hunger studies and those other studies, Jonathan, is that depending on which trimester you're in, the impact can be larger. The most vulnerable period is the first trimester. And what's really important about these studies though, is that these are extreme conditions, famines, right? So you have a real lack of food, lack of access, and often these studies are then translated to countries like the UK where we have access to food a bit too much normally, and it doesn't work that way. So I think what's really important to note here is that pregnancy as a metabolic state is incredibly resilient. What that means is that your body will take all it needs for the baby first and the mom can wait. So these amazing studies that help us to learn about development also show us just how resilient pregnancy is.

Jonathan: So if anyone is listening to this right now, either they're pregnant or they know someone who's pregnant, should they be worrying about the mother getting enough food to make sure that their child doesn't have these long-term issues that you're describing?

Lucilla: Yes, absolutely. And it's particularly relevant to people who are underweight.

Jonathan: Yeah.

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Lucilla: But yes, I mean, it's all a matter of balance and common sense. I mean, those were extreme conditions, but they told us so much about the possibilities of lifelong consequences. Obviously, undernutrition is an issue, but overnutrition is at the moment a much bigger issue.

Jonathan: It's something we've always been told, like, you need to make sure you take certain vitamins when you're pregnant. You know, you need to eat certain sorts of things in order to build this whole new baby. That seems very logical and clear. It's much less obvious that somehow if you're eating too much, you are going to cause any problems. But I think that is what you were also getting at, Lucilla.

Lucilla: Yes, I was. We're conflating two things. One is the energy intake; too much energy intake, calorific intake, will lead to a larger baby. The question about which nutrients are important, which we could consider as well, is a really different sort of area: which are the most important micronutrients and vitamins that a mother should be taking. And I think there is a lot of discussion about so many different variables and women do get very confused, and I think it boils down to a few. So let's talk about the obesity side of things first of all, because in the UK and in most high-income countries—even India, South Africa, and so on—obesity in pregnancy is becoming a real pandemic-type problem. And first of all, the obvious consequences of it are maybe infertility before somebody gets pregnant, but during pregnancy it's the explosion of gestational diabetes, the higher risk of preeclampsia, then lots of risks at delivery in terms of postpartum hemorrhage, stillbirth... I mean these are all relative risks and a substantial increased risk. You're not necessarily going to have a bigger baby, but it's become a major obstetric problem. So before we think about the long-term effect on the baby, we have to think about the conditions in pregnancy which the mother might develop, which then in turn lead to problems for the mother's health, potentially in the long term, and also for the health of the baby. The infertility side of it, I think a lot of people who are overweight or living with obesity don't appreciate that they may not get pregnant in the first place, and that comes as quite a shock. I think that's one of the problems that is not widely understood about the fertility issue. And then once people do become pregnant, they are very surprised if they get diabetes very often. So I think we, as the professionals in this community, need to make people understand a little bit more about the potential consequences. If you are considering having a family, the most important thing is to try and get to a normal weight before you conceive. And then a lot of this will go away.

Jonathan: And could we talk a bit more about the factors that can influence fertility, the chances of conceiving? And within that, I'd love to pick up on your very surprising answer to that question at the beginning about the father's lifestyle also influencing the child's future health.

Lucilla: Even before the embryo is formed! So this is why preconceptual health is really important. The mother's ovaries can be affected. The cells within the ovaries, the oocytes, the eggs—if you look at them under a microscope, if you like, or in the laboratory, they have potentially metabolic defects. So they don't work as well as they should. You can show that they have more oxidative stress. That means they have free radicals. They get damaged by having damaging molecules. So if you are living with obesity, your eggs might not be as healthy as others. And if you look at the early embryo, the same thing: it metabolically can be suboptimally healthy. So you start off with that potential disadvantage. Not everybody, as I say, is gonna have that. So don't get too worried about it. But we know that people have looked at the eggs and the early embryos. I've done this myself in rodent studies, but there are some very good studies from people who've given their eggs and early embryos from IVF for research, which was a very helpful thing to do for us to understand. So we know there are metabolic potential problems, and that's probably why there's a high rate of miscarriage in people who are living with obesity. So that's part of the problem. Now, the fathers... yes, less understood, but certainly the sperm can be affected by obesity in the father. There's good evidence that the sperm, again, have free radicals and oxidative stress, and the actual epigenome, the genetic makeup of the father's sperm can be affected—the actual health of the genes in the father's sperm. Studies in animals have shown unequivocally that if the father is living with obesity himself, it can have an effect on the health of the embryo. I think we should emphasize relative risk. So you know, there is an increased risk and that risk might be small or greater depending on yourself and your fitness and your health, you know? But there is an increase in risk.

Jonathan: I'm guessing from the fact you're talking about this, though, this is not like a... this just changes things by 1%. This is quite a meaningful—

Lucilla: Yeah, it's a meaningful change. Yeah.

Jonathan: Is the only thing that matters before conception whether or not I'm overweight, or is there more to do with the quality of my nutrition?

Lucilla: The most important thing is folic acid intake. And so, I'm very pleased to say that our government here in the UK has now followed America and Canada and a lot of other countries in putting folic acid into our flour. Only at the moment into white flour, but you know, hopefully it might go across the board and into all sorts of flour. But this will help because about 80 to 90% of women who are of reproductive age have inadequate folate status. You can measure it in people's red blood cells. And there are about 60 to 70% of people who have a level of folic acid in the red blood cell which is low enough to cause congenital defects in the children. This is a massive problem in the UK. Most other countries have had folic acid in their flour for a long time, and this problem has gone away to a certain extent, but we are only just getting there in the UK. So this is very important.

Federica: And I think what this touches on is the fact that we live in a world where we often have too much energy, too many calories, but actually not enough nutrients. So we have this double burden. We have people who are maybe overweight or living with obesity, but they're not getting enough nutrient-dense foods. If we think about where folate comes from in food, it's beans, it's leafy greens... so it's the foods that we're not eating enough of. And luckily now public health has intervened and said, okay, we need to fortify bread, which a lot of people eat every day. But then you have this discord, right, Jonathan? Where you have people who are living with obesity or overweight, but actually their nutrient status isn't optimal.

Jonathan: That's right. And presumably I could be listening to this, I'm not overweight, but also I could not have all the optimal nutrients if I'm looking to conceive.

Federica: Yes. It goes both ways because the quality of our diet is suboptimal at population level. Right? So it does vary with income, education level, there's lots of variety within that. But at a population level, we're not really hitting the mark when it comes to nutrient intake.

Lucilla: In terms of nutrients that we're particularly worried about, one is folic acid, the other two are iron and vitamin D.

Federica: Yeah.

Lucilla: So those, you know, I was saying maybe you don't need to take multivitamins. The majority of the population would benefit from being aware of the issues about iron and folic acid and vitamin D, but we don't give iron to everybody who's pregnant because they might get iron overload. We have to measure the hemoglobin first of all. We have a profound amount of anemia in our population of young women, about 40%. Obviously if you're anemic, you don't have enough oxygen with a baby, and you may be very tired, you may be more likely to have postpartum hemorrhage and things like that, and infection. So those are the three really important micronutrients to think about before pregnancy and in pregnancy.

Jonathan: What else could potential parents do if they're looking to increase their chances of conceiving?

Lucilla: A balanced diet is the most important thing. I mean, nutritionally, just a balanced diet. The other important element is physical activity. You know, you're not suggesting you should suddenly start running 20 miles a day or whatever, but to increase your level of physical activity. Because physical activity improves your glucose control. And as we mentioned, one of the most important complications of pregnancy in women affected with obesity is getting gestational diabetes. And we could talk about that, because that requires a lot of visits to hospital, it requires monitoring your blood glucose and so on. So being physically active will help your glucose control. And then when you become pregnant, carry on. Don't stop with physical activity.

Jonathan: Don't stop with physical activity.

Lucilla: No, don't stop.

Federica: No, keep it up and don't start new exercises or contact sports, right?

Lucilla: Don't stop playing football.

Federica: But certainly keep it up. It's super important. Also, birth is quite hard physically, so being physically active is helpful for that. Not smoking, not drinking. It still needs to be said because there's actually quite a high proportion of couples trying to conceive who smoke and drink. So reducing those is really important, cutting them out altogether. And then there's some evidence around caffeine intake, which I'd love to get your take on, mostly during pregnancy. But if you are like me and you drink four coffees a day easily, you might consider switching that down a little bit if you're trying to conceive so that when you then are pregnant, you can easily have your one cup of coffee a day.

Jonathan: What do you think, Lucilla?

Lucilla: I think the jury's out on that, to be honest with you. You see one study saying it's bad and another study saying you might be okay. But it's a stimulant and like alcohol, which is a stimulant, it's good to abstain but not completely. I mean, alcohol, yes, but not caffeine.

Federica: One cup of coffee a day.

Lucilla: Yeah.

Jonathan: So one thing I'm always conscious of whenever we talk about anything to do with pregnancy or breastfeeding or any of these sorts of things, is that there's an enormous amount of guilt associated with not being a good enough parent and particularly not being a good enough mother. And there's probably a whole bunch of people listening to us right now who are already pregnant, who are saying, well, I didn't do any of those things and I'm worried my iron level was too low, or I wasn't doing any physical activity. How worried should they be? What can you say to them?

Lucilla: Well, the statistics are you'll probably have a normal pregnancy because we're talking about risk, increased risk. So please don't panic. But there are things that you can do, and one of the most important things is just to eat a really balanced diet. Now, I think it's important to recognize you can get inexpensive foods. For example, oily fish, which is recommended that you should eat in pregnancy. There are some expensive oily fish and some very inexpensive ones like mackerel. And then if you're living a sort of chaotic lifestyle, maybe you are a single mother, those things will all affect your pregnancy, to add onto the problems of nutrition. So we absolutely understand that. We've been doing studies in South London recently to try and pinpoint exactly what it is that interferes with a healthy pregnancy. It's not just nutrition, there are all these other factors. And we in population health need to address these to actually really improve the situation holistically. In the UK, the government has put funding into community hubs now, which I think are doing a really good job in being accessible to anybody living near a hub. Mother and child hubs we have in South London are extremely good, where advice is freely available. You can address your worries and have a chat with someone. Mostly you're going to be okay, but it is of course sensible to think about this. There's your baby there, and you need to be helping your baby as much as possible, but don't panic.

Jonathan: I love that we have now successfully conceived in this conversation just now, which is brilliant. I now have this vision that the fetus is there and we started talking about misinformation, which is definitely something I wanted to talk about. Because there is so much information online now and in social media about pregnancy and what you should and shouldn't do, and there's a lot of contradictory information out there as well. So I'm actually really keen to understand what the latest science tells us. And I think I've just heard something very reassuring about how resilient, in fact, the fetus is, and that you don't need to be perfect. But I'd love to talk a bit more about what we both know you really do need to make sure you are doing, but also then maybe touch on some of these things that are a bit controversial.

Lucilla: Okay. One of the first big intervention studies I was involved with was to recruit pregnant women living with obesity into a study whereby half of them were allocated to what we call the intervention arm, so that they saw a health trainer every week for about 10 weeks. We gave them sensible dietary advice, which was tailored to their personal needs—in terms of expense and what they were able to do in terms of physical activity and so on. And then the other half just had normal care from their midwives and so on. The women were very receptive to the dietary advice, and they did improve their diets. We looked in the blood samples of these ladies, and their metabolism was better. Things that we could measure, like glucose and abnormal glucose products, all were good and went down. So that was very good. The dietary advice was good. We've just been talking about an affordable, healthy diet. There is this misconception that you should eat for two, and we mentioned that before: absolutely no need to eat for two. In the UK we recommend that women need just an extra 200 calories in the third trimester. You don't really need it, the baby is looked after very much by the mother's metabolism, and the mother metabolizes her own fat to help the energy get to the baby. And physical activity, which I can't really emphasize enough. There's been a recent collaboration which has put together all of these studies, which was in the British Medical Journal just a few weeks ago, stating that physical activity is looking to be a good one to focus on, and physical activity does help you improve your blood glucose levels.

Federica: At an individual level, I think it's important to remember what we talked about a bit earlier: that physiologically your body will do everything it can to get what it needs from your diet and from your lifestyle to support your baby's growth as best it can. There's a lot of misinformation online that says, you know, one stressful event in pregnancy will ruin your child, or one cookie that you eat will change the epigenome, the genetics of your child. That is not the case. Pregnancy nutrition requires adequacy, not perfection, not optimization. A balanced diet, so it contains all the food groups. You have lots of fruits and vegetables. No surprise here, but fiber is really important for pregnancy outcomes. Yeah, so lots of plants, and plants can be inexpensive. Tinned beans, frozen berries, and then your oily fish, maybe a maximum of six eggs a week will do fine, tofu if you like it. So just a variety of foods. Try to avoid some things. I found in some of the research I've done that sugar-sweetened beverages can be harmful. So reducing those in your diet, that's the one thing. Drink water, drink water. But otherwise your body has evolved to support the baby's growth—sometimes at the cost of the mother's nutritional status. So don't worry too much. And as Lucilla said, try and get support if you can. If you live in a country where there is support for pregnant mothers, access the care as much as you can, get that extra input so that you can have a healthier pregnancy.

Jonathan: Can we talk a little bit more about how important the time is that, you know, I spent in the womb for my long-term health? Because the example you gave was, if I'm really small, there might be this long-term impact. But now you're saying that's not really the problem anymore because our parents are all getting enough calories. You know, bluntly, why do I care?

Lucilla: Yeah. Well the problem is that all the studies, and I've done some myself, show that when the mother is in the overweight and obese categories, it is directly related to obesity in the child as the child is growing up. I mean, it's an extraordinary, strong relationship. What's that about? Because that is worrying, because if a baby is born large, that baby has a higher risk of becoming obese. Obesity tends to track through childhood and then into adulthood.

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Jonathan: And Lucilla, if the child is born large and has a higher risk of obesity, what will that mean for their health and their health risks?

Lucilla: The health of the child later on is likely to be affected by their obesity. So they may get diabetes, they may get more cardiovascular disease. And this has been reported. I mean, observationally, this happens. So if you're looking in the UK at the moment, when children first go to school, about 9% of them are already obese, and by the time they get to nine or 10, 20% of them are obese, and then that tracks through to adulthood.

Jonathan: You're saying 9% of children when they first go to school, they're still age four—

Lucilla: Yeah.

Jonathan: —are already categorized as living with obesity. What would that have been like 50 years ago? None?

Lucilla: None. None at all.

Jonathan: Like zero. So it's an immense change. And you are saying it isn't just because they're being given bad food after they're born.

Lucilla: No. So it's a combination. We know from a lot of research that the fetus is very susceptible to extra calories, and so the baby grows. We also know that the baby's brain is very susceptible to those extra calories. And what we think is happening is that the area of the brain which controls eating behaviors seems to be permanently rewired. I mean, not in a huge way, but there's very good evidence that this happens. That area of the brain is called the hypothalamus. There are imaging studies with MRI which suggest if you look at the brains of adults whose mothers were living with obesity, you can pick up this change in the hypothalamic structure. So that is worrying, thinking you might be rewiring that part of the brain. The child might be born more susceptible to eating more or having less satiety.

Jonathan: I think you are saying that even while I'm in the womb, because of the food that my mother is eating—and maybe all the food she's been eating for many years before I'm born—this is actually going to affect the way that my brain is developed. This hypothalamus in my brain is actually being rewired and this is gonna affect my hunger and therefore how I eat later.

Lucilla: Yeah.

Jonathan: And I guess none of that sounds as surprising as it would've done a few years ago as we now see these amazing GLP-1 drugs. Because I'm hearing this and saying, well, this all sounds quite linked. Do we know whether this is playing into this, Lucilla?

Lucilla: When a baby is getting too much glucose basically crossing from the mother—too much sugar going from the mum to the baby—the baby grows adipose tissue. So it starts getting a bit fat. The adipose tissue is the cells of fat mass. They start producing this hormone called leptin when they get bigger and there are more of them, and leptin goes across into the brain of the baby. And this leptin is known to change the way the cells of the brain develop. There is absolutely unassailable evidence for that. So if there's too much leptin, it can actually stop the neurons in the hypothalamus, in that area of the brain which controls appetite, from growing normally so they don't get to where they should. So it's the actual development of fatness in the baby which feeds back to the baby's brain with this hormone. And that can change the way the baby's neurons and cells of the brain develop. We don't always have a mechanism for these things, but there is a mechanism which suggests that's happening. And you know, it does go back to the GLP-1 receptor agonist story because that's all about hypothalamic control.

Jonathan: If the mother has too much sugar in her blood, then actually the fetus can end up putting on too much fat in the womb. Then it makes this hormone, you mentioned leptin, that goes into the brain of the baby. That actually means that part of their brain, you call this the hypothalamus, which is around managing hunger, actually doesn't grow properly. So we actually understand now sort of the set of mechanisms, I feel like. As a small baby after you're born, we all think putting on fat is great. It's sort of the thing that you're most looking for, right? When the baby is born, it's actually quite skinny generally, and the thing that you worry about as a new parent, I remember, is putting on weight. So why is it that putting on weight here in the womb is a bad thing?

Lucilla: Because the brain is at a rapid stage of development, and postpartum, the hypothalamus is pretty much developed. So in utero, in the womb, the fetal brain is particularly susceptible.

Federica: If a baby is born with a lot of fat tissue, that's not helpful for long-term health outcomes. But also this, what we call rapid rebound weight gain. When babies are born a bit skinny and they gain a lot of fat very quickly, that's actually also not that helpful. What you really want ideally is for a baby to be born a normal weight for their gestational age, with normal fat distribution, and then to track that and not have these random weight gains with more fat tissue because it does then alter their long-term metabolic health.

Jonathan: Got it. I guess what I'm thinking is a healthy baby is quite a chubby baby, right? At least in my mind. You know, you don't expect a baby to be as skinny as you would expect a child when they're older.

Federica: That's true. Yeah. There's adequate adiposity, there's a nice level of rolls, we want them, yeah, exactly.

Lucilla: And so what we are seeing is when they first go to school, they've got that fat, which they've probably had all the way through the first two and a half or four years of life. We should look at the diet of children postpartum after delivery up to the time they go to school. It's probably the most important time for prevention of obesity and I don't think most governments have really taken that on board yet. But do you wanna go back to diabetes in pregnancy and glucose?

Jonathan: I think you were saying that having too much blood sugar in the mother's bloodstream is a problem.

Lucilla: So a lot of people who are living with obesity have a risk of getting diabetes in pregnancy. So why is that? Because they haven't had diabetes beforehand. Now they may have, but generally they haven't. When anybody becomes pregnant, your blood sugar goes up a bit, and that's a really normal response to pregnancy. Your hormones, estrogen and progesterone, the hormones that go up massively in pregnancy, they actually help push glucose up a bit. It basically helps the glucose get across into the baby. So it's a good thing. Now the problem about that is if you are also living with obesity and you have a large fat mass, then those fat cells will contribute to what we call insulin resistance. So what's insulin resistance? Insulin controls our blood sugar, in you and me and everybody. But if you become resistant to insulin, it means that the glucose in your skeletal muscle, in your liver, in your fat tissue, doesn't get taken up into the cells of those tissues enough. And then what happens is the glucose stays up in the blood. So the mother who has got a high BMI, high body mass index, when she becomes pregnant her glucose will go up normally, but then her high increase in fat mass will make her insulin resistant, and that can be enough to tip you over into full blown diabetes. Pregnancy itself is a risk for gestational diabetes, particularly if you are living with overweight or obesity. We have an epidemic of it at the moment.

Jonathan: So there's a huge number of people who don't have diabetes, get pregnant, and then while they're pregnant end up having diabetes, which means there's a very high level of sugar in their blood. And then when you stop being pregnant, you stop having the diabetes again.

Federica: Yes. But then you are at much greater risk of getting long-term type two diabetes because pregnancy is really a metabolic challenge, right? You have naturally increasing blood glucose levels, which as we've just said is a normal part of pregnancy. But it does put a challenge on your body to then distribute that glucose effectively. And if you are already a bit compromised, so if you're already overweight or living with obesity, then your body doesn't quite have that resilience to deal with that. And I think this is really important: when we talk about elevated blood glucose in pregnancy, we're not talking about the odd piece of cake or the cookie, because in women who aren't metabolically compromised, your body will deal with that. It's much more systemic. When your blood glucose is elevated all the time, that's when it starts to become a problem and lead to issues like large babies.

Jonathan: What can women do to help reduce their risk of gestational diabetes during pregnancy?

Federica: Well, so as we've heard from Lucilla, I think the biggest thing is to try, if possible, to reach a healthy weight before you conceive. That's the best way. And I know that still around 50 to 60% of pregnancies in the UK and the US are not planned, but if possible, if you are thinking of having a baby or you are not using contraception so you could fall pregnant, it's useful to think about reaching a healthier body weight before you fall pregnant. That's the best thing. During pregnancy, as we've heard, changing your diet to be healthier will help with your health, but it won't necessarily reduce the risk of gestational diabetes. The best way to do that is to move, so physical activity, because physical activity directly reduces blood glucose concentration whilst you're moving. And I think this is really important. Often when we think about movement in pregnancy, people think, oh, I'll go for like one walk and I'll be done. But actually it's movement throughout the day that helps to really regulate blood glucose, and post-meal movement after a meal really helps your body to remove that glucose from the blood because it goes straight to the muscles that are helping you to go for a walk.

Jonathan: Is it dangerous to do strenuous exercise when you're pregnant?

Lucilla: Well, you would not recommend strenuous exercise. We did a study of people who went on parkruns who are pregnant. Absolutely fine to carry on running. Don't start doing parkruns if you've never done one before, but you don't feel you need to stop. So anything which is not unsafe, like having a fall or skiing or something when you really might hit yourself in the tummy. But carry on if you've been doing it before.

Federica: As Lucilla said, it's not a good time to start a new activity. Now, if you've been completely sedentary and you are entering pregnancy and you want to change your behaviors, then things like walking, low-impact exercises, yoga, swimming, and lighter weight or bodyweight resistance are recommended. So keep doing what you are already doing. If you're not doing enough, stick to the things that are safe to do. If you haven't been doing them before, basically.

Jonathan: I'd like to wrap up on pregnancy by really explicitly talking about what you should and shouldn't eat to maximize the health of your fetus. Yeah. With like very clear, actionable advice.

Federica: When you're trying to conceive and in pregnancy, the dietary recommendations don't change that much. It's try to have a mostly whole-food diet, so where possible buy the ingredients as whole foods, whether tinned, frozen, dried, doesn't matter. It can be affordable. We talked about tinned mackerel, we've talked about jarred chickpeas. All these foods are fantastic. Try to aim for a diet that has a variety of foods, lots of different plants, 30 plants a week is a really great place to start. So you're including herbs and spices, nuts and seeds, whole grains, fruits and vegetables, legumes and pulses. So if you think about it as a plate, Jonathan, about half of your plate is made up of plants. Then you've got a quarter of your plate made up of complex carbohydrates. So whole grains. This is your barley, your rye, your quinoa, pearl barley is delicious, I love it. And all these lovely carbohydrates, complex carbohydrates, sweet potatoes. And then the other quarter is where you would choose your preferred protein source. So that might be chicken, it might be eggs, it might be tofu, it might be your tinned mackerel. Oily fish three times a week is recommended. Eggs are great, but no more than six a week. So that's like the outline. And then try to choose healthy fats, like extra virgin olive oil, or if that's too expensive, you can use olive oil or other seed oils, which are healthier alternatives for cooking to things like butter or lard, for example. And we've talked about drinking as well: important that you don't drink any alcohol and important that you have water as your main drink. So really avoiding sugar-sweetened beverages. Sugary drinks are—

Lucilla: Are really important to avoid. Yeah.

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Federica: So that would be like the overview. I'm quite cautious with caffeine, so I actually recommend to the women I work with that they reduce it right down to one cup a day, but that's a smaller point than everything else we've just covered.

Jonathan: What about the paleo diet? I've heard some people promote that as a really good idea, and I've also heard this recently: pregnant women should eat six eggs a day. What are your thoughts on these?

Federica: Okay, so anything like a paleo diet, which excludes entire food groups, is not recommended in pregnancy. I should side note that if you're vegan and you want to continue with a vegan diet in pregnancy, you can, but you'll just need support and make sure you're supplementing micronutrients.

Lucilla: Yeah.

Federica: What I'm seeing online is so much misinformation about certain foods that you should absolutely be eating in pregnancy. There's this myth that you have to have four or six eggs a day to reach the adequate amounts of choline to have a baby's healthy brain. This is just completely wrong. You don't need to eat that many eggs. About six eggs a week will do it, and there are other foods that contain choline. And as we've discussed, your body's really good at getting what it needs in pregnancy. So if you have a varied diet, you'll get the nutrients you need. And in terms of micronutrient supplementation, we've talked about folic acid as being the really important one, vitamin D especially in the winter months, and iron if your iron has been found to be low. And some women will look at iodine as well. Iodine is another one of these micronutrients which in the UK we don't have iodized salt for; a lot of other countries do around the world. So you might think about iodine.

Lucilla: Yeah, there is evidence that iodine isn't as high as it might be. But again, if you have a balanced diet, it should be fine.

Jonathan: Brilliant. I'm conscious of time and you said there's a thousand days, and I'm worried that by my calculation, we're only at about 280. So presumably the last thousand now is getting the baby to two years old, which is a period that I only dimly remember with both my children because I was constantly tired. Maybe we could talk a little bit about breastfeeding to start with. How important is that, Lucilla?

Lucilla: It's very important for all sorts of reasons. Because it helps the baby's immune system develop and it gives the right composition of nutrients in the mother's milk. And the baby doesn't need anything more than the mother's milk in the first few months of life.

Federica: As Lucilla said, the actual composition of breast milk is the ideal combination for babies. It's essential for gut microbiome composition. A lot of the sugars contained in breast milk are not actually accessible to us as humans. They're there solely to feed the gut microbes in the baby.

Jonathan: It's amazing.

Federica: So there are specific gut microbes that are essential for infant and children's health, and they can only eat these sugars in breast milk. It's fascinating the amount of microbes that live in it, the specific sugars that are in it, all the immune system proteins that go into the breast milk. So for example, Jonathan, if I'm breastfeeding and I get a lift with somebody with a cold and they sneeze, my immune system will pick up that cold virus, make the antigen to combat it, and put it into my breast milk to my baby within two hours.

Jonathan: Within two hours?

Federica: Yes. So that the baby doesn't get the cold.

Jonathan: That's real?

Federica: Yeah.

Lucilla: It's super important.

Federica: Fascinating, super important. Yeah. So it is essential. Now I have breastfed both of my girls. I had real difficulty with my first, it's really hard, right? And we don't have enough support for breastfeeding mothers at all. Too quickly, some will say, well just give them some formula and get some rest, right? So the system doesn't support breastfeeding mothers. In other countries, human donor breast milk is given before formula milk, which makes more sense when you think about it for the baby's health. So I think what's really important in this conversation is to point out that A, we need to support mothers way more with breastfeeding. We need to make it easier for them, educate them on some of the difficulties. Something as simple as an adequate latch can completely transform breastfeeding. There's a lot of perceived inability to breastfeed. Women think they're not making enough milk, and they're like, I'm not making enough milk for the baby. That's actually physiologically not necessarily true. Women think they're not making enough milk, but they actually are. But this perception makes them stop breastfeeding. So education is really important. Understanding how magical breast milk is for the baby's health is really important. Also, empowering women that even if you only breastfeed for a bit or even if you're combi-feeding—so if you're breastfeeding and formula feeding—that's actually still great. Still better than not breastfeeding at all. That's not to say that, of course, formula milk as a replacement isn't adequate, right? They've been carefully formulated, they're very carefully screened, and you can't just make up your own formula.

Lucilla: And all of them are very carefully screened.

Federica: So they are obviously created to be able to support a baby's healthy growth. So I think it's also really important to note that if you do formula-feed your baby, that is absolutely fine. It's just that formula milk has not yet been able to fully replace all of the benefits that we see from human breast milk. It's just not there yet.

Lucilla: Especially the immune side of things.

Federica: Yeah.

Jonathan: It's fascinating what we know about how much it's feeding your gut and also this link to the immune system. It's really extraordinary.

Lucilla: And when we looked in the mother's blood—mothers who were breastfeeding and not—we found that their metabolism was much healthier when they were breastfeeding. I think it's worth saying, particularly as we were talking about women living with obesity: one of the problems about obesity is actually that it might be difficult to breastfeed. It could be that there's a hormonal effect on producing milk. It could be just a physical problem about the discomfort of breastfeeding. Of course, from the mother's point of view, breastfeeding does help weight loss after pregnancy, which is another problem for the mother.

Federica: Interpartum. So the weight that women gain and keep between pregnancies is actually a big risk factor for women's future health. So if you put on weight for your first pregnancy, and then you're not quite able to lose that weight before your next pregnancy, that puts you at higher risk of obesity later in life. Which is actually a really important point.

Lucilla: And this increases the risk of problems happening in your next pregnancy. Weight gain between pregnancies is related to more gestational diabetes, more preeclampsia, and more stillbirth in your next pregnancy. And this is also a preconception health message too, before the next pregnancy: try to regain your pre-pregnancy weight as much as you possibly can.

Jonathan: So I would like to sort of come to a conclusion now with what we should be feeding babies at the point they move off breast milk or formula? Because I'm hearing all this conversation about just how important the nutrition is for us from the point of a fetus onwards. What should they be eating?

Federica: So babies need to be introduced to the healthy, varied diet we've been talking about throughout this podcast. Important nutrients to consider as soon as you start weaning: iron is one of them. So babies' iron stores do go down throughout infancy. There is iron in human breast milk, and the form that the iron is delivered in human breast milk is really highly available. So there's also this myth that human breast milk doesn't provide it. It does, but children do need a lot of iron as they're growing up. So iron-rich foods: beans, lentils, meat and poultry and fish, all of these foods contain a lot of iron. So that's great. They need to be exposed to as many foods as possible. So, a wide variety of foods, we want them to try vegetables and fruits, whole grains. But you know what's wonderful about weaning is that they'll try pretty much anything. Yeah. So between ages six months and a year, you can put sauerkraut, you can put all sorts of foods and the baby will just go for it. They develop individual taste later, so expose them to as much as possible. Spices, don't be shy. Put garlic! But don't add sugar or add salt to food. No.

Lucilla: And don't give them foods which are full of sugar and salt.

Federica: People often say to me, "Oh, your kids love natural yogurt. How did you do that?" Well, I introduced them only to natural yogurt. I didn't give them flavored yogurt straight away. So be really mindful of not buying prepared products that have added sugar and salt and are marketed as a healthy option for children.

Lucilla: And particularly follow-on formula.

Federica: Yes.

Lucilla: Children do not need follow-on formula and it is marketed as such. It has a very high sugar content. And then yogurts containing fruit. Natural yogurt is much healthier than yogurt containing fruit because it's full of sugar.

Jonathan: And what about all these pouches?

Lucilla: Yeah. Well.

Jonathan: We pretty much fed our kids on these pouches. As you get a little bit past the weaning stage and you're all busy and you're out, I'm pretty confident I might not have been doing the right thing.

Federica: It's absolutely infuriating, right? Because these products are marketed as being healthy, ideal for weaning, ideal for finger food. It's absolute BS, right? Essentially those front-of-pack claims are there to help sell product. They've got nothing to do with health. And these pouches are mostly water, sugar, and nothing else. There was a big analysis that was done, led by the BBC in the UK for a TV show, and they analyzed lots of pouches, Jonathan. They found that in the pouches, they didn't even have the nutrients that they claim to have on the front of the pack.

Jonathan: Because you're talking about, this is like a pouch that says it's an apple pouch.

Federica: Or things like sometimes they say "Complete meal: sweet potato and lamb pouch," right? They're not just the fruity pouches or the flavored yogurt.

Lucilla: Preservatives, and they have been heated to extend their shelf life.

Jonathan: So this is like ultra-processed food hiding as the best thing you can do for your child.

Federica: Junk baby food. It truly is junk food.

Lucilla: Junk food, real junk food.

Jonathan: And should I therefore be worried about giving my child a piece of fruit? Because after all, that is also very high in sugar.

Lucilla: It's not nearly as high.

Federica: And the whole fruit gives you all the fiber. Yeah. And the phytonutrients. More children now know how to open these pouches and packets than know how to peel a banana.

Lucilla: You know, one of those pouches contains more sugar than the daily requirement of a child for the whole day. About three and a half cubes of sugar in one of those pouches. It's a scandal. And this is, I mean, probably one of the major factors for follow-on formula and these pouches. Yeah. It is why our children, when they go to school, have such a high incidence of obesity.

Federica: And dental cavities. Right.

Lucilla: We have! And dental cavities is the other thing. Because actually the sucking of these pouches is very bad for teeth. And as you probably know, having all your teeth out when you are a young child is the most common operation in pediatrics at the moment in the UK.

Jonathan: Is there any single piece of actionable advice that you'd like to give to parents for their babies at the point after they're born? Just to wrap up with, and maybe start with you, Lucilla.

Lucilla: To think about what you're feeding your child and to look on the packages that you are buying at the content, because they will have it, but it's very poorly disguised at the moment. So be very conscious of the amount of sugar and the amount of salt that is in some of these products. But the most important thing is to feed natural foods, to feed fruit, to feed lentils, and to vary the food of your child so they have a wide breadth of a healthy diet.

Federica: Try to take the opportunity to enjoy food with your children. So make delicious meals with them. Get them involved in preparation. Get them used to seeing the whole foods so that in their minds and as they grow up, these whole foods become what they relate to as food. So the banana, the orange, the apple, the bean, the fish... get them used to as much whole food, whole food ingredients as possible. And drinking water. Make them drink water. Just water. Not the juices. Yeah, just—

Lucilla: Water.

Jonathan: I love it. We've covered a lot of different things, so I'm gonna just try and pick out the highlights. I think the thing that I start with is this idea that actually in the first thousand days you are almost built as a human being, which I hadn't really thought about because you're still very small. But actually what you're describing is so much is shaped, and then it's just sort of getting a bit bigger. And that's part of why this is such an important time period, that we now know that many of your long-term health risks are actually going to be shaped by what's happened to you very early. Which I think does mean that this is a really important period. And I think I'm really shocked... I think you said that in the UK, 9% of children at the age of four are already living with obesity. And I'm pretty sure that number would be even higher in the US.

Federica: It is higher in the US. Yeah.

Jonathan: That this starts actually even before pregnancy, I think is another thing that is really amazing to me that you're describing. If either of your parents are living with obesity, this can affect not just your chance of having a baby, but also affect their health. But there's already things that you can do in terms of your diet. You talked about folic acid multiple times. So I think one of my takeaways is, you know, if you're a woman, you definitely want to make sure that you're taking folic acid, but also things like smoking and drinking really have an impact. Then we talked about pregnancy and I thought what was interesting is I normally think about pregnancy as being all about how you must avoid certain foods, and you haven't once talked about avoiding food. You've really talked about making sure you're eating healthy food, and when you are talking about avoiding food, it's all about avoiding junk food rather than, "Oh my God, you mustn't eat a piece of steak." I think that's fascinating. And I think the other thing is we now understand a lot of the science of what's going on. So when a mother becomes pregnant, her blood sugar increases. That's natural. But because of the sorts of foods that we're eating today, many pregnant mothers actually have blood sugar that is becoming too high. And this is what you call gestational diabetes. And we now know that in the fetus, that raised blood sugar is actually getting into them, it's causing the fetus to put on more fat. And that's sending hormones into their brain, literally reshaping their brain in a way that is going to be with them for life, which is basically gonna make them hungry for junk food. So it's just like, I mean, as a food manufacturer it sounds brilliant. I feed the mother this junk and the baby is already hooked on this stuff before it's even born. This is basically what you're saying, Lucilla.

Lucilla: Yes. Effectively.

Jonathan: I think that the idea that we allow this not only to be legal, but to be advertised without restriction is extraordinary as you describe that. And I think it also ties into our understanding of why so many of us are having to take GLP-1s and things like this, if this is all the way back to what happened to us in the womb. It's not just about what you eat during pregnancy, however. I think it is really interesting how much you talked about physical activity, both in terms of being able to manage that blood sugar excess, but also we now know that it's good for you in a way that I had no idea. The advice about what you should eat is actually very similar.

Federica: Yeah.

Jonathan: Federica, it's the sort of advice that you talk about all the time here. And it's sort of the opposite of this processed food. It's this diet that's really good for your microbiome and all these whole grains. Being very conscious here, it sounds like, about added sugar. And so, you know, we're never very keen on these sugary drinks and fruit juices, but here it's like much more important. It's not just you, it's thinking about the baby. And then at the end we talked about, well, what happens at day 280 or so? You get the baby. And I took away two things. The first thing is we've known for a long time that breastfeeding is good for the baby, but we now understand so much more about why. And that there's actually literally food in the breast milk that is only for the baby's gut bugs, is wild. And then this example that like two hours after you experience a cold virus, you could already be pumping antibodies in your breast milk to your baby is amazing. I think throughout this we talked about not feeling really guilty if you can't do this, and you said you're not gonna ruin your child forever by not being able to breastfeed, but not to give up and to try and make sure you've got the support that you can to do that. And then we finished, I think, with the fact that the sort of food that again, food manufacturers are pushing for babies and young children is pretty shocking. You said one pouch for a baby that has this great label on it saying it's a "complete meal" has more sugar than the entire requirement for the child in a day, and that our children do not need to eat these pouches. And that similarly, follow-on formula, which I wasn't so familiar with, is a huge problem. They don't need it at all.

Federica: It's a huge problem. It is, yeah.

Jonathan: Thank you so much. I wasn't expecting this to be such an eye-opening "the food industry is really shocking" episode as I think it's turned out to be. I would like to maybe just wrap up again with a message for anyone who is listening to this, who's just an adult like me thinking: "So my parents completely screwed me up and does that mean that there's nothing I can do and I should give up worrying about what I eat?"

Lucilla: What we've been saying is that you may get an increased risk by what happens in the womb. But what we haven't really talked about is how you can optimize that risk as a child grows up. And of course you can. If you think you have a tendency to obesity, then all of the things we've been talking about, mothers and babies, apply as you grow up. So it's not the end of the world, you can actually mitigate against this. So it's just being aware that you might have that fundamental increase in risk and being particularly careful about what you eat and what your child eats. And it's as simple as that. It's certainly not a doom message that we're trying to get across at all, but it's just a take care message. Much more important.