The truth about organic food, according to science

What does "organic" food mean? And how do you know if something's organic? Of course, foods tell you if they're organic in massive letters on the packaging. And they cost way more.

But what makes a food organic? Is eating organic better for your health? And are the benefits worth the expense?

Luckily, Prof. Tim Spector is here today with answers. Tim is one of the world's top 100 most cited scientists, a scientific co-founder of ZOE, and the author of the bestselling book Food for Life: The New Science of Eating Well.

Stick around until the end, and you'll also find the answer to a question we get often: Does Tim eat organic?

If you want to uncover the right foods for your body, head to, and get 10% off your personalized nutrition program.

Follow ZOE on Instagram.

Episode transcripts are available here.

Is there a nutrition topic you’d like us to explore? Email us at and we’ll do our best to cover it. 


[00:00:00] Jonathan: Tim, thank you for joining me today.

[00:00:02] Tim: Fantastic, once again.

[00:00:03] Jonathan: And I think this is going to be fun because we have never talked about organic food before, and I'm actually not sure that you've really talked very much about it publicly at all.

[00:00:12] Tim: First time for me as well.

[00:00:13] Jonathan: So I'm excited and I'd like to start, as always, with our quick fire round of questions. Are you ready, Tim?

[00:00:20] Tim: Go for it.

[00:00:21] Jonathan: And we're gonna be really strict today. Yes. No. Or maybe. All right. Are there more nutrients in organic food?

[00:00:30] Tim: Yes.

[00:00:31] Jonathan: Can pesticides in non-organic food affect our health?

[00:00:35] Tim: Yes.

[00:00:36] Jonathan: Okay. Not sounding too good for the non-organic food so far. Is there one food that you would definitely buy organic?

[00:00:44] Tim: Yes.

[00:00:46] Jonathan: If you're on a budget, is it crucial you eat organic food?

[00:00:50] Tim: No.

[00:00:51] Jonathan: And then I'm gonna let you have a whole sentence, Tim, what is the one myth about organic food you'd love to dispel?

[00:00:58] Tim: That you can't trust it at all, I think is the common one that you can't trust the labels, therefore don't bother.

[00:01:05] Jonathan: Got it. So it's all a lie. So you might as well just give up and just buy whatever.

[00:01:09] Tim: 10 years ago I was very skeptical about organic food. I didn't really bother. I just saw it as being expensive. I just thought it was marketing hype, getting us to spend more money on things.

[00:01:21] Jonathan: Tim, can we just start at the beginning and explain. What does it mean for something to be organic?

[00:01:27] Tim: The key things about organic food are that it doesn't contain antibiotics. Antibiotics are not given in that food chain, not given to the animals it doesn't contain any pesticides or herbicides or actual chemical additives of any kind and also the third thing is it doesn't include any artificial fertilizers.

[00:01:49] Jonathan: And Tim, what's the difference between a pesticide and a herbicide?

[00:01:52] Tim: A pesticide is also known as an insecticide, so it kills actually the living bugs like your beetles and other things that are eating the plants and a herbicide, like Roundup or is something you put on, you spray in your garden that kills weeds.

[00:02:11] Jonathan: So it's actually killing other sorts of plants rather than the first one, killing sort of animals.

[00:02:15] Tim: It's killing plants and it's also used in organic food production to actually dry out the crops just before you harvest them as a sort of extra way of making the harvest easier. So generally we don't refer to herbicides much, we group them together with pesticides. So often if I people are talking about, they're including herbicides and this chemical, which many people have in their garden called Roundup. They're the general rules. And when you buy something organic, it doesn't guarantee that it's totally free of all these things. It just means the levels will be very much lower.

[00:02:51] Jonathan: And so just to make sure that I've got that, this organic sort of has these two elements. One is about the way in which the food is being grown, and I think about this as somehow just being less destructive to nature in that environment, right?

Like not killing all the bees and everything else. And there's almost a second part, which is how is it healthier for me to consume it because it's got less pesticides and these sorts of things that are on the food. And is that right, Tim? It's like the combination of both of these as we think about organic.

[00:03:20] Tim: Yes, there's an environmental impact of these products and we know that, for example, extensive use of fertilizers in fields runs off into our rivers and is actually causing major problems for the environment and fish and other hazards that we're seeing certainly in the UK and many other countries, overuse of fertilizers.

The other chemicals also leach into killing other animals. And some countries use many more aggressive insecticides, for example, pesticides than others. So there's a whole group called Organophosphates which include the family of some nerve agents and things like this, that, like Novichok that some countries like Sweden have completely banned, but are very common in the US and used at some low levels in the eu, but still allowed. And obviously around the world there's very different rules. If you're getting food from Asia or India, you don't really know what's been used in those countries.

[00:04:26] Jonathan: So I'm listening to this and thinking I probably don't want nerve agents in my salad, but tell me, Tim how worried should I be about pesticides in the food that I ate?

[00:04:37] Tim: So most of these pesticides are checked to be safe in humans by studying mice and rats and seeing if it gives them cancer or what happens to their liver or other organs. They generally pass those tests, but they've never looked at, other aspects, more subtle aspects of what happens to them. So these studies where rats are given organophosphates and you can see changes in their gut microbes, means that they produce chemicals. And we've talked before about their gut microbiome as little chemical factories.

And depending on how they're triggered, they'll produce different chemicals, vitamins in response to that. So these produce kind of weird chemicals when they're given organophosphates to eat. They respond differently, cause abnormalities and can switch in the rat at least some of the sex hormones.

So the phytoestrogens that occur naturally. So, there's course for concern based on Rat and mouse studies, but I've never believed them on their own. You know that it's only in mice. Only in rats. You can actually produce any result if you really want to just by doing 20 experiments and picking the one that worked and no one generally publishes the other 19, but so big human studies, the ones to go for. And then you've got as usual this whole range of epidemiology. So from the observational study that we just take a group of people that you follow for 10 years and ask them based on their starting diets did you ever eat organic?

Yes or no? And often because we weren't thinking about it 10, 20 years ago, the date is quite crude. So there's one study from Belgium that followed 58,000 Belgians, and found that people who had non-organic food ended up putting on more weight than people had organic food. Now, That could be totally a health bias.

[00:06:31] Jonathan: I was gonna say we, this is one of the things we talk about all the time, right? Which is that people don't, they're not like rats. You can't make them do what you want 'em to do. So people have this whole bundle of their behaviors. So presumably people who eat organic food tend to also be like, they smoke less and they are more careful about what else they eat and they probably are healthier. And so this stuff is very hard to untangle, right? In the studies you're describing where they're just observational.

[00:06:56] Tim: They observe it, but they do try and adjust in their models for the fact of these healthy effects that you're describing. So they would adjust for smoking, it would adjust for exercise, adjust for education level, et cetera, et cetera.

And they still fine, but. It was a one-off and no other studies really shown differences in weight. Then there was another study in the UK of six, 680,000 people. Again are other crude study cuz lar very large numbers and they, that has yes no, do you eat your organic foods or not. But they did have good data on cancers and they didn't find any big effect on cancers in that study.

But they did show An increase in one, one cancer called Non-Hodgkin's lymphoma, which is a cancer of the blood. Not that common but they had increased rates. Then there was the Nutri-Santé study. Which is in France, which has actually much more detailed information cuz it's really been designed for studying nutrition and they've done similar studies on ultra processed foods and they've followed about 58,000 people, I think it is for a period. I think it's about nine years. And they found that there was a increased risk of cancer of most cancers by about 25% including non-Hodgkin's lymphoma in the people that weren't taking organic food. And the organic food group were protected by about 25%.

[00:08:28] Jonathan: So that's a huge difference, right? 25% lower risk of cancer. How do you..

[00:08:33] Tim: So some of that could still be this fact you haven't adjusted for these healthy behaviors, but it's big enough to think there might still be something real in there.

And again, this other interesting finding this non-Hodgkin's lymphoma comes up again. And also there was interesting, the in breast cancer went up after the menopause and so certainly again, Increasing just ratting up. Slight worry about this, and if we looked at, obviously that's just organic, whereas is non-organic and in if you took the people taking glyphosate. This is exposed to glyphosate roundup.

[00:09:13] Jonathan: Which is what? Can you explain what that is?

[00:09:15] Tim: Roundup is this herbicide that is in most weed killers, and you looked at people with high exposures because they're doing parks or sports fields or spraying or spraying crops, for example, the epidemiology studies have again suggested that they're not all in agreement, but they overall suggest there is a slight increase in cancers and again, particularly non-Hodgkin's lymphoma. So there is some evidence that. Cancers are increased through long-term exposure to these chemicals.

It's far from proven and but there is this struggling with non-Hodgkin's lymphoma, which seems to be more consistent than the other data. So cause for concern that way. There's also there was a meta-analysis of about 20 small studies looking at infertility and problems during pregnancy, again, suggesting a slight effect, but the studies were not well performed and so low quality.

So our sort of clarity on saying yes, it definitely does, that is not quite there. And there was also several studies looking at attention deficit in younger children. Showing there was a relationship there. Again, poor quality studies, but enough to be concerned that we should be sorting this out in a way that we no one is really addressing.

And the final study actually comes from our own twins where we were the only ones to look at the effective organic food on the gut microbiome. It was an observational study. We took 60 I think four pairs of our twins working with some environmental epidemiologists Robin Minaj was leading the study and looked at several hundred different residues, insecticides, and herbicides, and found that nearly everybody had some organophosphates type residues in their blood and urine.

[00:11:27] Jonathan: And so just to make sure that I've got that, this is where I'm happily eating my pears and my apples and my leaks and whatever I'm not out in the garden spraying this on my hands. This is from the food I'm eating. And you are saying that I went into your hospital lab along with 10,000 other twins and you took my blood and you could actually find bits of this remnants of this pesticide in my blood. Is that is that right?

[00:11:53] Tim: Yes I think it was over 90% or something until, so almost everybody had some, yeah. So in your blood and urine, nearly everyone's got these insecticides and about 50% of people had detectable levels of these herbicides, the glyphosate, the Roundup, and we looked to the gut microbes to see if these chemicals were having an effect. Was there a difference between people with high exposures, high levels in their blood and urine versus low levels? And there was a clear correlation. And so people who were eating more fruits and vegetables had high levels of these chemicals.

And they also had different changes in their gut microbes. So the gut microbes were. Producing different chemicals in response.

[00:12:41] Jonathan: And so people listening to this could be like, oh, so that's great. I'm gonna give up my fruit and vegetables and I'm going to go back to my meat and saturated fat diet and I'm gonna avoid all these horrible risks, Tim, that you're talking about that I might get more cancer is that the right takeaway from this?

[00:12:58] Tim: No.

[00:12:59] Jonathan: Okay.

[00:13:01] Tim: If you go back obviously people who eat lots of fruits and vegetables compared to people who don't, or are on ultra processed food diets of minimal fiber are likely to live 10 years longer and have half the risk of heart disease, diabetes, dementia, all the common chronic diseases, and they're gonna weigh less so that's, we've known that the fiber is really important.

The plants are really important. The polyphenols, the defense chemicals in plants, are really important for orbits of our body. Now what we're talking about here is I think We are talking about a possible 10% increase in cancer risk, which in terms of a lifetime risk is a fairly small one for vast amount of people, and not every cancer, we're only talking about a few specific ones where there's.

There's evidence and something like Non-Hodgkin's lymphoma is a rare cancer most people haven't heard of. I don't know the exact rates, but it's gonna be less than one in a few hundred people get it. I haven't given up eating fruits and vegetables when I can't find organic. Okay. To me the advantages far outweigh any risks.

So we are talking about a subtle difference here. That probably only makes a difference if we're having them regularly and for decades.

[00:14:24] Jonathan: But we'd still rather not have all of these pesticides. is what you're saying?

[00:14:27] Tim: You’d definitely rather not have it, particularly at certain times in life where I don't think we talk much I enough about it, but there's critical times of pregnancy or feeding young children when you know there's so much happening to the body, the brain, and really don't want unwanted chemicals washing around that have all these effects, we still don't really understand. Unless there's no way around it.

[00:14:51] Jonathan: Now you, we've talked a lot about the negative things that might come from pesticides and therefore organic food is almost just saying, oh at least it's got less of those bad things. But one of the things I've heard is that organic food is supposed to have more nutrients in there, and that's part of why the idea that the soil is alive with its own microbiome, all these things is better. Is there any truth in this, Tim, or is that just good marketing?

[00:15:17] Tim: There is some truth in this. And there was a meta-analysis about eight years ago, about 300 tiny little studies that put them all together and it showed that on average the organic produce had more minerals in it. It had less cadmium, which is like a toxic mineral. And importantly for me, it had around 30 to 40% more polyphenols.

[00:15:47] Jonathan: 30 to 40%. Okay so that's enormous.

[00:15:49] Tim: So that's increasing your polyphenol intake by 30 or 40%. And that really is important. So just to remind people, that's the defense chemical that you find in plants that occurs naturally and is in the, often the tips of leaves or the bitter part, or it's in the berries or these things naturally.

These are the things that naturally protect the plant against insects and the environment that it turns out the organic ones who are raised in our sort of traditional ways have more of, and I think that's really fascinating because people have, there's no one's exactly sure why, but I think.

The hypothesis I like is the fact that if you give the, if you surround these plants with insecticides and spray use taken away their you don't need that defense and you give them masses of fertilizer. So they just grow. So all they really want to is grow. They're just like these giant sumo babies that are growing big and fat as fast as possible, and environment is like super easy for them and they have no defenses.

And if you grow too fast you're likely to get, have a really bad immune system because all the focus is on growth, not on prevention.

[00:17:02] Jonathan: I love this. So it's a bit like, so they are like the plant equivalent of homosapiens living here in the 21st century in the developed world. Are they where we can sit on the sofa all day, we don't need to do anything and we now know that you really need to go to the gym. It's really important for your health. And you're saying it's a bit similar that these plants, the environment is not stressed enough.

[00:17:22] Tim: They're really couch potatoes. They're sitting there in the sun. Everything's done for them. They don't have to bother, they don't have produce these defense chemicals like they used to

[00:17:31] Jonathan: Because they're no longer fighting off the these insects. And also, I guess they always get the right water and they get the right fertilizer. That means, I guess thinking back to some of the things you've talked about, the microbiome, that they end up being different from the sort of foods we might have eaten until a hundred years ago. So they have a lot less of these chemicals that our bodies would've just assumed they would get naturally with the food because way back in, in the past No plants were being treated like this. So everything presumably had all of these defense can of chemical ‘cause they were all in this fight for survival.

[00:18:06] Tim: Yeah, exactly. And it's the same thing. If you look at how chickens have evolved how we've. You grown these massive chickens in just a few weeks. They don't have anything like the nutrients and things of the old scrawny chickens that we used to eat. And I think all our food has been primed for growth and size and to look good. But it when you look into the detail, you're getting actually less of the things that you need. So if you do buy the organic equivalent, you're gonna be getting Around 40% more polyphenols, less toxins in there. You'll be getting slightly more minerals on average. And you are gonna be getting a slightly better product. So the idea that it was a con, which was what I believed 10 years ago is not really true.

[00:18:54] Jonathan: So I'm going to ask the question that our listeners have really wanted to ask from the beginning. It was like our number one question that we got from all our listeners beforehand, which is, Tim, do you eat organic food?

[00:19:05] Tim: I do, Jonathan, yes. I know you might be surprised cuz when I'm out traveling and we go out. We've been traveling around the US and places. I don't insist on organic food.

[00:19:17] Jonathan: No, that's right. You generally seem quite relaxed about it and much more focused on whether you're eating plants.

[00:19:23] Tim: Yeah. Exactly. Getting a diversity of plants is my number one priority, and I know it's hard to get diversity of plants and organic, and so that bar is just really too high, especially when you're traveling and you don't have those options. You do at home. But at home I would say 75% of what I'm eating in terms of plants, fruits and vegetables, et cetera, is organic.

[00:19:47] Jonathan: And are you eating this organic food cuz you're worrying about cancer or are you eating this organic food because you're thinking you're getting like more of those sort of good polyphenols you were talking about?

[00:19:57] Tim: I got really into this as I was, six years ago, I started writing my book Food for Life, which has a big section on this if anyone's interested. It wasn't just about cancer. There was this these polyphenols. It was the microbiome aspect of it. I didn't really want lots of extra chemicals for decades going to my microbiome that on the one hand I was trying to build up in a good way. So this just seemed to be detrimental and I can now afford it. So what I I've now done. So I've changed my views on organic produce, but I think people shouldn't worry too much about things that they only do occasionally. I think what we're seeing here is this is something that you worry about for things that are in your diet regularly. And you're gonna be having them regularly for years.

[00:20:44] Jonathan: Can we talk about that for a minute? Because I think you're in the nice position where, your children have grown up and you're affluent enough to be able do this without a lot of pressure. Organic food is really expensive. How should people think about those trade-offs? And I'd love to talk about maybe are there particular foods where these levels of the pesticides and everything are really high and you should be really worried versus others. What are the foods where the pesticides are likely to be worse?

[00:21:12] Tim: Breakfast cereals that contain oats.

[00:21:14] Jonathan: Okay. That's incredibly surprising. I thought you were going to give me a fruit. Tell me about oats.

[00:21:19] Tim: Oats because they're often raised in, in damp countries, they are sprayed just before they're harvested to dry them out. Okay. And so this gives them masses amounts.

And because they're wet, they absorb all that glyphosate. And so their levels are 5 to 10 times more than many other grains. So that is something that is not particularly a health food that I think people should go out of their way if they do love oats. And I know you used to be a big oat eater, although you're not anymore. And you can afford it. Either switch something else or go jump. Particularly if you're trying to give your kids something which you think is healthy. I think that you could be giving them high levels of particularly this herbicide glyphosate. Rice is another one that came up interestingly in some surveys as being quite high in pesticides. And we do know that if you get, certainly areas of India and Pakistan, do have a problem with runoff of arsenic into rice paddy fields. If you're getting cheap rice from certain places, you may be ingesting a lot of chemicals and in general, fruits and vegetables that contain a lot of water will tend to absorb these chemicals more than others, and where they particularly attract in insects as well.

Cucumbers, pears, nectarines. These tend to have quite high concentrations and everyone loves strawberries. I love strawberries, but in tests in the US and the uk, they commonly get tested as being above the safety levels. So we have these standard safety levels.

[00:23:01] Jonathan: And this's again, for these herbicides you're talking about?

[00:23:03] Tim: This is pesticides and herbicides. So these are the insecticides, the organophosphates and all the glyphosates, really high levels. That's the sort of thing you should be wary of that if you. If you have strawberries just once a year, it's probably not worth worrying about it. But if this is like part of your regular thing, just see if you can get organic strawberries.

[00:23:25] Jonathan: or presumably swap to a different fruit that has lower levels.

[00:23:29] Tim: Yes. And other berries. I now, I didn't use to, but I now try and get organic blueberries if I can you can often get 'em frozen. Interestingly they, and they're not very expensive. If you buy the frozen organic barriers and you stick 'em in the freezer.

[00:23:43] Jonathan: I was just thinking about this morning. I get a lot of organic tinned food and a lot of organic frozen food because after podcasts that we've done in the past where I've discovered that actually like frozen vegetables and tinned vegetables are good, we now cook a lot of that at home. And what's interesting is that the price of still like organic tinned beans is still incredibly cheap. So is that one of the areas that again,

[00:24:08] Tim: Absolutely. Yeah. You picked up on three really good tips for people is, yeah, organic frozen food is really good. They don't have the same costs because it obviously, it probably costs more to transport organic food cuz it does go off quicker. So you've gotta be much faster. You can't just leave it around and warehouses for as long as possible. You don't tend to store them in those chemical bags and things. So that's a good tip about frozen foods, canned foods, I think. Beans do come up in some surveys as being high and pesticides. So buying, paying 10 p extra or whatever for an organic bean can is good value compared to the fresh one.

[00:24:47] Jonathan: It's all a bit scary. You're talking about like these pesticides and herbicides. What can I do if I've got this, can I wash this? I was always brought up by my mother, interestingly, like I should wash the fruit.

[00:24:58] Tim: Washing helps, but it doesn't get it down anywhere near to organic levels, so you remove a little bit of it. And you can peel them, that will remove some more and some particularly these that's probably one reason to peel cucumbers which I never used to do by the way. I'm not too lazy. But if you can't get an nor organic one probably peeling, it gets rid of perhaps half, but you're still. A lot of it might go be beyond the skin.

So another little trick is if you are washing stuff, add some sodium bicarbonate, baking soda. That is very good at removing.

[00:25:29] Jonathan: Does that take a lot more of this away?

[00:25:31] Tim: Yes. A lot better than just water. So that's a little tip that doesn't cost it to cost anything, but there are certain fruits and vegetables that are actually pretty safe.

ZOE's favorite fruit. The avocado which we know is pretty generally healthy seems to absorb the herbicides and insecticides on the skin so you don't eat the skin, so you're eating the flesh. And that's pretty free of any nasty problems. Similarly, an onion, you peel away, you don't eat the onion skin.

So that's really well protected. And There, there are other examples like that, that are more the drier fruits and vegetables that don't absorb the water, that have got a skin. Mango is another one. They're actually pretty good because again, you're not eating the skin. So there, there is list of ones you don't have to worry about.

And there are lists in the US has a list of these. Each year they do produce a list of the 15 best and the 15 worst offenders that people can look at. Although each country's gonna vary and locally the amount of spraying and things will vary a lot. We know that certain parts of the UK just.

If you live in Norfolk, the spring is enormous. So it's very hard to avoid some of that on most of the produce, whereas other bits of the country the produce has much less.

[00:26:58] Jonathan: And I definitely have this vision that this is particularly bad in the states. Is this true?

[00:27:03] Tim: Rules are much laxer in the states. They allow more organophosphate use, more chemicals that are banned in Europe. And I think there's generally much less checking of these levels. So the levels are generally higher. In the US and we've talked about antibiotic levels. They're also much higher still and the general chemicals used in agriculture, it's still a bit the wild west.

[00:27:28] Jonathan: So your differential to moving to organic is gonna be even higher there then?

[00:27:33] Tim: It is, yes. And there, there are different big differences between countries as well and the pricing as well. It's interesting there are. Many countries in Europe where perhaps 25% of the produce is organic. Places like Sweden, Austria, et cetera, in this country, we're probably below 3% in the uk I think it's similarly low levels in the us but luckily it is really growing fast.

So it is doubling every 10 years. So I think. It's a movement that's not gonna go away. And I think it's something that everyone needs to know about.

[00:28:07] Jonathan: Tim, you're definitely convincing me that I should be buying more organic food next week than I was last week. We asked this question right at the beginning, and I just want to get the clear answer to it. We said if there was one food that you were going to buy organically what would it be? And I'd love to get the answer.

[00:28:24] Tim: Probably tomatoes actually, because I eat tomatoes nearly every day. And I think to me that's more important. I was gonna say strawberries. Cause I love strawberries, but I don't have them every day.

So I'm less concerned about it. So I think that would be my main answer because It, it's, you've gotta think of that long-term exposure of foods and getting high quality tomatoes. I've tasted Italian and Spanish ones and not only they taste better, if you can get. The organic versions of those, they are pretty incredible.

But again, you can get a can of organic tomatoes for not much more than the non-organic version. So it's about people thinking for themselves, but what they would change, what do they have regularly, what could they improve that would make a much bigger difference to their long-term health?

[00:29:14] Jonathan: Brilliant, Tim, thank you so much. What I'd love to do is a little summary to try and cover all the different areas that we've gone through today. So first we talked about what's organic food, and the key thing actually is what's not in it. So what I understood is you don't apply pesticides, you don't apply fertilizers, you don't have antibiotics.

If it's an animal, then we talked about does it really matter for our health? And I think my takeaway was it's not totally clear. There's a bunch of studies. The biggest question seems to be about cancer risk. And I think that what's clear is it's not a massive difference or it would be really clear, but that I think you think that there is some area of risk and particularly maybe for one or two particular cancers.

The net result of this, I think, is that you were saying you should be particularly cautious if you're pregnant or if you're feeding sort of small children because you're at that point where everything's being, being grown and at the same time, In comparison to the benefits of eating fruits and vegetables, this risk is really small.

And so you would definitely say eat a plant eat a fruit, even if it's not organic versus something else, that's so much better. But if you have the ability to afford these choices, then organic is good. And that actually a big part of that is because of the extra stuff you get.

So you're saying it has maybe 30 or 40% more of these polyphenols that you talk a lot about as being like the food for our microbes and and therefore this organic food, even if I can't taste the difference my microbes can so try and feed them that way. If you can, We talked a bit about what you do and you said that you're probably eating, I think 70% organic, Tim, is that right?

[00:30:54] Tim: Yep.

[00:30:55] Jonathan: And that's a big change from 10 years ago when you were very suspicious and actually you've come to the view that it is better. And then I think we talked about some specific things that you should worry about. And I was amazed to hear oats and interestingly strawberries also as one of the highest.

But on the other hand, things like avocados you mentioned actually really low. And my overall takeaway was there isn't a sort of, you must do this completely. It's more think about how you might be able to introduce this if you can't afford it. Don't stress too much. What you might be able to do though is to look at some of the things, particularly tinned and frozen, for example, where you might actually be able to shift quite a bit and it might still, in fact be cheaper than the things that you're buying fresh.

So there is a range here and I guess as always you would love there to be much more research so that these answers were clearer than I guess you're able to give today. Tim.

Yeah, we should be definitely pushing for more research, especially on the microbiome, long-term effects, but also we should be pushing for transparency on labels.

How does this food rank in terms of its insecticide and pesticide levels? Just so the customer knows exactly what they're buying and they're not having to go and read my book every time they're in a supermarket. In everything we're talking about, it's about transparency in food.

So people can make their own choices given the right information, and it's not hidden.

Brilliant. Tim, thank you so much for coming in as always, I've learned a lot and I'm sure our listeners have as well. A pleasure.

Thank you, Tim, for joining me on ZOE Science & Nutrition today. If you want to understand how to support your body with the best foods for your health, then you may want to try ZOE's personalized nutrition program.

You can get 10% off by going to As always, I'm your host, Jonathan Wolf. ZOE Science & Nutrition is produced by Yella Hewings-Martin, Richard Willan and Alex Jones. See you next time.