Ultra-processed food: are all UPFs bad for you?

Erica McKoy: Ultra-processed foods are everywhere, but they often lack what your body needs most. And we’ll be discussing the food pairings that will help boost your nutrient absorption. Today, let’s unpack how you can get the most from your diet. Welcome to this podcast from Which?.

Hello, it’s Erica here with a brand-new episode of our healthy living podcast, bringing you expert advice and recommendations to help you live your best life. So, it’s episode two. Let’s welcome back our public health nutritionist, Shefalee Loth.

Shefalee Loth: Hi, Erica.

Erica McKoy: And the founder of City Dietitians, Sophie Medlin.

Sophie Medlin: Hi, Erica.

Erica McKoy: We did it last week. I really enjoyed doing it. I want to throw some rapid-fire questions at you two. I know this will make you feel uncomfortable – I’m okay with you two feeling uncomfortable because we’ll get into it in the episode. On a scale of one to ten, Shefalee, how worried should we be about ultra-processed foods?

Shefalee Loth: I’d say six.

Erica McKoy: Okay.

Sophie Medlin: Yeah, I was going to say seven, but I think we’re in agreement.

Erica McKoy: Okay. Three UPFs, ultra-processed foods, that we shouldn’t ban from our diets?

Shefalee Loth: Okay. Bread, breakfast cereals, and I would say Marmite, obviously.

Erica McKoy: Sophie?

Sophie Medlin: Oh, I’d add in things like baked beans and fish fingers and things that are useful staple foods.

Erica McKoy: I think there’ll be lots of people that are very angry about that. The internet often hates everything we say. Should I have a cup of coffee with my high-iron breakfast?

Sophie Medlin: No.

Erica McKoy: That’s a quite – we know that one. Okay, cool. Is there any sort of one ingredient that is a bit of a red flag on an ultra-processed food item?

Sophie Medlin: I think with some of my patients, I would tell them to be careful with emulsifiers, and I would tell them to be careful with sweeteners, preservatives. These ultra-processed ingredients, but not everybody and not all the time.

Erica McKoy: Can you be healthy but eat lots of ultra-processed foods?

Shefalee Loth: Probably not. I think when we talk about a healthy diet, we talk about variety. And so, if you’re only eating ultra-processed foods, it’s going to be harder to get certain nutrients into your diet. I do understand that’s not a quick answer. Sorry, sorry.

Sophie Medlin: I would say, and I’m going to try and keep this snappy, in the research on ultra-processed foods, even the people with the best health outcomes still consume some ultra-processed foods, but not lots of ultra-processed foods.

Erica McKoy: Not very simple answers from our brilliant experts, but that’s okay. I think there’s lots to unpack here. I know we’ve spoken about it; the internet goes crazy for it. We did some videos about ultra-processed food and there were some people that reacted to the ultra-processed food video. When we are talking about ultra-processed food, what are we talking about?

Shefalee Loth: The whole term ultra-processed foods came about because of a study that looked at the processing of foods. So, it didn’t look at the nutrient content of foods; it looked at how processed foods were and it gave them four different stages. So, there’s things like fresh fruit and vegetables would be unprocessed, and then milk or butter would be minimally processed, and then you’ve got your processed foods which might be canned chickpeas, for example.

And then this category that is ultra-processed is basically – the way it’s defined is it contains ingredients that you wouldn’t see in your kitchen at home or has more than five ingredients. It’s all quite abstract really. And even experts can’t agree what an ultra-processed food is and what isn’t. So, the problem is that if you looked in a supermarket, the majority of food, because it covers so many, would probably come under the ultra-processed banner. But that doesn’t mean they’re all equally unhealthy or that none of those are good for you.

Erica McKoy: We mentioned beans, we mentioned Marmite, bread, and you said that you wouldn’t remove them from your diets. What’s so special about these ultra-processed foods versus, I don't know, a Mars bar?

Shefalee Loth: Okay, so there’s lots of things really. Nobody thinks a Mars bar is healthy. So, a Mars bar is obviously high in fat, it’s high in sugar, and while it’s got energy, it probably doesn’t give you much nutritionally. Whereas if you compare that to baked beans or sliced wholemeal bread, these products, whilst they are ultra-processed, they also contain fibre and they contain vitamins and minerals and nutrients that are important to our diets. So, just because they’re ultra-processed doesn’t mean they don’t have a valuable role in a balanced diet.

Erica McKoy: And Sophie, we spoke about emulsifiers, sweeteners, stabilisers as being something that you’d be a bit concerned about for some people. What do they actually do to the body?

Sophie Medlin: Good question. I mean, some of it we don’t really know is the answer to that, but we know that they’re not naturally occurring and so we’re not – not that we’re not supposed to have them, but in high quantities, they’re probably not doing us any good. Emulsifiers are made to help to combine fat and water or fat and other liquids. So, for example, in a plant-based milk, there’s oils in there, either from the natural ingredient like almonds or added, and they need to emulsify, mix together with the water and stay in that cloudy state and not be separated. So, that’s the sort of thing where emulsifiers are used.

The concern with emulsifiers is that they are getting into our bowel, and on the lining of our bowel are these little finger-like projections called villi. There’s a single cell between the food that’s passing through our bowel and our bloodstream on the other side of these villi. And so, the outside of that cell contains something called a phospholipid bilayer – so, a layer of lipids. And of course, if emulsifiers are designed to break down lipids and make them emulsify, there’s a concern and it’s been demonstrated in animal models that that could potentially affect the gut lining.

Now, there’s not big convincing studies in humans yet, but there is concern enough there for people like myself who work with people who’ve got things like inflammatory bowel disease to be saying, "Let’s be careful with emulsifiers if you have got inflammatory bowel disease." And again, I’m not saying check every single label and eliminate everything from your diet; I’m really talking about the things you consume and have in your house regularly.

Then with things like preservatives, they’re obviously there to kill bacteria. And we now know how important our gut microbiome is as well as other microbiomes in the body, and so consuming something regularly that contains something that’s designed to kill bacteria, even if it’s in a tiny quantity, could be potentially having a negative effect. And then sweeteners – again, so the jury’s still pretty much out on sweeteners and I think it probably will be for the rest of my lifetime, but we do know that they have a potentially negative effect again on gut bacteria. So, it’s something to look out for and ultimately these are artificial ingredients that we don’t necessarily want to be consuming in large quantities and in most of the foods we’re consuming. Ideally, they’re kept to occasional or treat foods.

Erica McKoy: I’m so glad as well that you mentioned the gut microbiome, because it is a bit of a buzzword at the moment; lots of people are talking about it. Can – and I’ve definitely heard some nutritionists out there say that once you have too much of certain processed foods, you can mess up your gut microbiome. Is that true? Is that true that there’s maybe potential for there to be irreversible damage? Or is it reversible? Can we kind of get it back to a healthy state?

Sophie Medlin: Yes. So, when we’re talking about the gut microbiome specifically, there’s nothing that’s irreversible. So, for some people – and we’ve perhaps talked about this before on this podcast – but some of the patients I work with may have had twenty years of gut health problems that may be rooted in the gut microbiome. That’s going to take a long time to recover and get better. But if you’ve had, I don’t know, a weekend of eating ultra-processed foods and drinking alcohol, your gut microbiome’s going to recover very quickly, the same as if you’ve had antibiotics or you’ve had a gut infection, for example. Your gut bacteria responds to everything that you’ve eaten every day and it can change from day to night. So, it’s constantly fluxing and changing, so there’s nothing that’s irreversible about your gut bacteria and your microbiome.

Erica McKoy: What are the risks of a diet that’s high in ultra-processed food?

Shefalee Loth: The immediate one that comes to mind for me is a lack of fibre. So, the more foods are processed, generally speaking, the more nutrients are taken out of them, especially fibre. And so, if you are eating a diet solely made up of ultra-processed foods, then it’s unlikely that you’re meeting your fibre target.

Erica McKoy: And what is the problem of not having enough fibre in your diet?

Sophie Medlin: Well, the first thing you’ll notice if you don’t get enough fibre is that your bowel habit will change. So, you’re likely to be pooing less and that’s likely to be uncomfortable and not particularly pleasant. But not getting enough fibre in your diet is associated with big health risks like increased risk of heart disease, increased risk of diabetes, increased risk even of certain types of cancer. So, there’s a really, really good reason to make sure that our diet is high in fibre, and actually that’s relatively easy to do, as long as we – you know, even if you were having an ultra-processed breakfast cereal, add some fruit to it and that’s going to make a big difference in terms of bumping up the fibre content.

Erica McKoy: Are there any other ways of bumping up our fibre throughout the day?

Sophie Medlin: Super easy stuff like choosing brown or wholemeal bread, pasta, rice makes a huge difference. Leaving the skin on potatoes and on certain vegetables as well – like keep the skin on aubergine, for example, or butternut squash – can bump things up really quickly. Sprinkling nuts and seeds on salads and things like that makes a huge difference. So, there are easy things that can be done that can make a big, big difference and get you from, like, 15 grams a day to well over your 30 grams a day if you need to.

Erica McKoy: And we’ve got a piece out that’s all about fibre and skin. What – like, I don’t think most people would link the two, but quickly – I know this isn’t the episode for it – but what is the link there with fibre and skin?

Sophie Medlin: What’s interesting is that we know that there is a gut-skin axis. So, if our gut’s not happy, that can be affecting our skin. So, perhaps that’s the crux there, is making sure you’re looking after your skin from within by making sure you’re getting a high-fibre diet and really looking after that gut microbiome.

Erica McKoy: Something I’ve also heard is that, for example, if you were to make a smoothie, that you’ve almost processed the fruit in that smoothie to get it down to a smoothie. Will that have less fibre in it than having, like, an actual apple or the actual fruit?

Sophie Medlin: Well, it changes the type of fibre slightly. So, if you think about skins and peels and pips and things like that as being insoluble fibre – so, those are the sorts of things that our gut doesn’t break down and digest in the same way, they sort of add bulk to the stool – and then the inside of things like inside of an apple, melon, mango, softer things like that, they’re called – that’s soluble fibre and that just draws water to the bowel and keeps the stool soft.

When we process them, like through making a smoothie, yes, we are changing the nature of the fibre and how it’s going to respond in the body, but you’re not reducing the overall fibre content. And really importantly with smoothies, we used to think that they could increase your blood sugars, but now the research shows us that actually, if you have a smoothie over whole foods, it actually reduces the response in our blood sugars. So, we haven’t got a concern about that. I would still say the same thing that I would say about anything else, which is if you’re having, I don’t know, six apples in a smoothie versus one apple that you might eat, of course you don’t want to over-consume anything, but if you’re having it in moderate amounts and you’re enjoying it and it’s a way of you getting fruit in, any fruit is better than no fruit.

Erica McKoy: Totally. Muesli is something we’ve been looking at at Which?. Can you tell us a bit more because some have been quite unhealthy and some is very healthy? What’s going on?

Shefalee Loth: So, the team here at Which? analysed around 85 mueslis on the market and we applied the nutrient profiling model to them, which is a scoring system. And actually, what we found essentially is that muesli is healthy as a breakfast cereal. But what the nutrient profiling model does is it takes into account those bad nutrients that people might think of, such as sugar and fat, but it also accounts for good nutrients such as fibre, protein, fruits and vegetables, nuts and seeds, etc.

And we found that whilst there is a range – like some mueslis are healthier than others – essentially mueslis are a pretty healthy go-to breakfast choice. Now, if you are choosing ones with chocolate in, perhaps not so healthy. But if you’re choosing ones with fruit and nuts and seeds, then obviously that’s really bumping up the fibre content and the protein content. So, those are better choices to go for. Certain ingredients can detract from the healthiness of your muesli and one ingredient we noticed was coconut. So, if your muesli’s got coconut in, it doesn’t mean it’s unhealthy, but actually it’s high in saturated fat, so you kind of lose some of those positive points because that drags it down a bit. That’s not to say don’t eat muesli with coconut in; it’s just something for you to be conscious of if you’re trying to limit your fat intake.

Erica McKoy: Yeah, something to be aware of. I think often when people are in the supermarkets, the labels are the thing that they go by because that’s all you kind of have to go by. When a supermarket or when a brand is making big claims of like high protein or low fat or low sugar, should we kind of be looking at them with a question mark?

Shefalee Loth: No, a lot of the time if something’s being labelled as high protein or a source of fibre or high fibre, there are criteria that they need to meet. So, it’s not just that any product can put that on. But the concern is that sometimes those kind of claims can give a product a health halo. So, you’ll think, "Oh, it’s high in fibre, so it must be really good for me," but actually then if you analyse the ingredients a bit more or the nutritional makeup and content, you’ll find that whilst it’s high in fibre, it also might be high in saturated fat or high in sugar because it’s got a really high fruit content. So, don’t just take those claims in isolation; think about the product as a whole and don’t just believe that because it’s got a health claim on it, it’s a healthy product.

Erica McKoy: Let’s talk about food pairings. We often hear about pairing supplements – last week we spoke about it with vitamin C and iron – this week, we’re talking about food pairings. What do we mean?

Shefalee Loth: So, essentially we’re talking about trying to eat nutrients at the same time that enhance each other and enhance absorption, and avoiding having nutrients together that compete for absorption. So, if you’re having a plant-based source of iron, it’s really important that you have it at the same time as a vitamin C source, because that will help the absorption. Whereas if you’re having an iron supplement at the same time as, for example, if you’re washing down your iron supplement with your morning cup of tea, the tannins in your tea are actually going to inhibit your iron absorption.

Erica McKoy: And we spoke about that at the beginning when I said, "Oh, if I had a high-iron breakfast and I washed it down with some coffee," you were like, "No, don’t do that."

Shefalee Loth: Yeah, that’s right. So, a mistake a lot of people make is having their iron supplement in the morning with a cup of tea, a cup of coffee, or even like a milky cereal. And actually, all of those will compete for your iron absorption.

Sophie Medlin: I remember working in my – when I was working in the NHS, which was a long time ago, and going to nursing homes where there was a really high prevalence of anaemia. And largely it was because they served tea – a cup of tea – with breakfast, lunch, and dinner. Every meal of the day, and so iron is being prevented from being absorbed properly essentially.

Erica McKoy: Wow. And that’s a small fix. But maybe – actually maybe not in certain places, it takes a while to get people on board with a change of diet – but for most people, I think it’s a small fix.

Sophie Medlin: Yeah, even if you – I mean obviously ideally drink water – but even if you had a glass – small glass – of orange juice with your meal, it can make a big difference to iron absorption for sure.

Erica McKoy: Again, last week we spoke about B12. As our listeners know, I’m a pescatarian, so I don’t eat steak. But if I was to have steak and a glass of wine, is there any issue there?

Sophie Medlin: I mean, alcohol is not good for our gut, right? It’s not good for us in any capacity, and of course it can affect absorption of things like B12. But if you’re someone who’s going out for a glass of wine and a steak, chances are you’re getting lots of B12 elsewhere in your diet, so it’s not necessarily something you need to worry about.

Erica McKoy: It kind of does feel like there’s some rules here about the pairing, and I think we kind of maybe run the risk of people feeling really unsure about what they can eat. What would you say to people?

Shefalee Loth: Yeah, I think you’re absolutely right and I think Sophie and I were discussing this earlier and it’s almost like people – maybe on social media – I would say need to have these hacks and these little sound bites, but actually the result is you end up scaring people unnecessarily. And actually, you know, if you’re eating a varied balanced diet, I would say don’t worry about having that wine and your steak, or even your iron at a mealtime, because you’re probably getting enough overall. So, whilst it might affect the absorption in a small amount, it’s probably not going to do that at a level that’s going to be problematic.

Sophie Medlin: Speaking of social media, I’ve seen a trend of people referring to things like oxalates and phytates and other naturally – tannins in tea – other naturally occurring ingredients calling them anti-nutrients as if they are killing off the nutrients that we’re consuming. And it is true that they can bind certain nutrients, but it is in a small amount that it’s going to be affected. So, for example, spinach and leafy greens contain oxalates which can bind calcium. So, if you’re having saag paneer, for example, then you’re probably not going to absorb all the calcium from the paneer cheese that you’re having it with, but you’re still going to absorb some of it and hopefully you don’t always eat saag paneer and nothing else, and therefore you’re going to be able to absorb your calcium sources elsewhere and it’s not a major concern. As Shefalee says, people just love having a sound bite and something to scare people with.

Erica McKoy: They do. Why? Are there any sort of food pairings that people are probably having anyway that they just don’t realise are just really good?

Sophie Medlin: Well, I think if we think about iron and vitamin C, so if you’re having either some fruit or a glass of orange juice at breakfast time, which people have done historically – people would always have a glass of orange juice at breakfast time – especially if you’re having an iron-fortified breakfast cereal, that’s going to help you to absorb that iron from your breakfast cereal. So, that’s a kind of classic one.

Another one is actually black pepper can be helpful for the absorption of nutrients. There’s not great data on it, but there is some suggestion it can increase the absorption of some nutrients by thousands of per cent. So, adding black pepper to food can potentially be very helpful for absorption of some nutrients. And another one to think about is especially if you’re vegetarian or vegan, trying to get complete amino acids. And if you combine legume – so beans and pulses – and a grain like beans on toast – easy – then you’re getting a complete source of amino acids there. So, sometimes it’s about vitamins and sometimes it’s about other things.

Erica McKoy: And Sophie, Shefalee spoke about the health halos. Are there any other foods that we should be a bit more aware of maybe?

Sophie Medlin: Yeah, I mean working with patients, what I find is that some people are really reliant on things like protein bars and they are ultra-processed foods. Some are better than others – the ones that are nut-based, for example, are going to be better than the ones that are birthday cake flavour – but we do need to be aware of that kind of thing because we think they’re really healthy when really they are a very ultra-processed food.

And then there’s other things like greens powder, which are ultra-processed vegetables in mine and Shefalee’s book at least. Then there’s things like protein shakes or particularly meal replacement drinks; they are ultra-processed foods. Things that people think are really good for them that are actually not so great for us and are really adding to that ultra-processed food intake. There’s also things like ready meals that have had fat and sugars removed and as a result of that, without having lots of additives and artificial things, they’re not going to taste good. And of course, if you want to lose weight it can be helpful, but ultimately losing weight by eating loads of ultra-processed foods is not a healthy way to go about it.

Erica McKoy: So, what should people be looking out for when they are going to the shops? Because shops are so big and there’s so many products and you just want to eat healthily. What should people be doing?

Shefalee Loth: I don’t think Sophie would argue with me here and it’s not rocket science: try to eat whole foods where you can. So, cook from scratch and buy whole foods and make your meals so you’re not relying a lot on these ultra-processed replacements. It’s fine, I think it would be impossible in this day and age to follow a diet that didn’t contain any ultra-processed foods, unless you were spending your whole time cooking from scratch and spending a fortune. Exactly. But for the bulk of your diet to be eating whole foods and then, yes, put some ultra-processed food such as sliced bread in there if you want to and you need to to make your life a bit easier.

Erica McKoy: If you want to find out more, we’ve got an article all about the food pairings, best and worst, out there. We’ll pop a link in the show notes. Are there any takeaways that we want to leave people with for this episode?

Shefalee Loth: Just because a food is labelled as ultra-processed, it doesn’t mean you need to be scared of it.

Sophie Medlin: And definitely don’t be scared of anti-nutrients and what the internet tells you about those; it’s nothing to worry about.

Erica McKoy: Shefalee, Sophie, thank you for joining me today.

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